Tuesday, January 31, 2017

Info Bleg for Precision Shooters Who Read Here

I know of two online sources for information:  Accurate Shooter and Precision Rifle Blog.  Of the two, Accurate Shooter, which includes 6mmBR.com and The 6.5 Guys, seems the more active and with more information.  I'm also aware of Sniper's Hide, but I get the feeling it's all by subscription.  I've barely scratched the surface on any of those. 

If you wanted to learn long range shooing, where's a good place to dive in and read?  What sources am I missing? 

My goal is to stretch out my shooting to our club's 300/600 yard range.  As is often the case, I want to shoot with what I have before I think about going for a full, new kit.  I think the demands for shooting 300 or 600 yards are not as great as shooting 1000 or more, and I expect many common hunting or predator rifles will be good at 600. 

I have two bolt guns, a .308 Savage Scout rifle and a Remington 700 in .30-06.  I wouldn't be surprised if the Scout would be fine at those distances, except for the forward mounted scope.  I understand that .30-06 used to be a common long range cartridge, but neither of those is considered a precision long range round by today's standards. 

My early model Savage Scout rifle. 

Monday, January 30, 2017

Had To Adult Today

More than usual.  Is there a world out there?   What's going on besides the Muslim immigration ban that really isn't a Muslim immigration ban?

The latest attack on freedom that's getting virtually no publicity is a ban on free soda refills enacted in France.
Published in the government's Journal Officiel website on Thursday and in force since Friday, the ban applies to all soft drinks or soda "fountains" in areas open to the public, including restaurants, fast food-chains, schools and holiday camps.

Out of bounds are unlimited "flavoured fizzy and non-fizzy drinks, concentrated drinks like fruit syrups, drinks based on water, milk, cereal, vegetables or fruit", but also "sports and energy drinks, fruit nectar, vegetable nectar and similar products".
Despite the book promising, "French Women Don't Get Fat", France claims to be in the same obesity epidemic as the rest of the western world, and is responding by attacking sugar.  The article in the Telegraph (UK) offers this cringe-inducing paragraph:
A recent health study suggested that half of French adults are now overweight. However; only 15 are technically obese.
(The cringe comes from the quote that only 15 French adults are technically obese; I'd be willing to bet that was supposed to read 15%.  If there really are only 15 obese adults in France, the government should be flogged for enacting this rule; if it's really 15%, the author of the Telegraph article should be flogged.)

Let me be clear here: I think the French Health Minister is largely correct in assigning too much sugar as the likely root cause of "the spreading obesity problem".  Not in the sense usually offered, that it provides "empty calories" that lead to weight gain, but that sugar messes with the body's hormonal systems, primarily insulin, and obesity is a metabolic disease caused by improper hormone responses.  I notice that the ban includes fruit juices and other sources of "natural sugars" that are just as dangerous, as well as sports or energy drinks that are also high sugar, but the ban doesn't seem to specifically exclude artificially sweetened "diet soda".  That makes much less sense to me.  

Despite that, I completely disagree with the government's actions.  I'm all about personal responsibility, and it should be peoples' choice to take advantage of more soda for free if it's offered.  Like Bloomberg's New York City soda ban, the state never seems to think that people can simply buy another soda.  The state never seems to think that people might drink less soda if they weren't forced to buy a certain size.  The state never thinks that perhaps someone might feel like just a little more soda, perhaps they feel like they need another mouthful or two, but don't want and won't drink an entire next cup.  The state never thinks. 

This is the sort of thing that happens when a socialized health system is in place.  People can't say, "but it's a bargain!  I get more soda for the same price" because it suddenly becomes the state's business if the population gets fatter.  Every Aspect of Everyone's Lives suddenly becomes state business.  Line up in front of the monitors for your daily exercises.  We're sorry to tell you, but you are not allowed to get your arthritic hip replaced because you're obese by our standards. 

Glenn Beck's producer, Stu Burguiere, links the reduction of choice at the soda fountain to the FCC's "Net Neutrality" also denying benefits to consumers that businesses want to provide. 
Net neutrality technically would ban what I think T-Mobile has done, which is give you free streaming of Hulu and Netflix and Amazon Video and all these things. A great benefit to the consumer.

However, net neutrality says, “Well, you’re not treating all companies equally when it comes to data, so you can’t do that.”

And the activists have fought to try to get that overturned, so far unsuccessfully.

But, I mean, these are benefits. These are making your life better. You’re getting more for your money, and yet government wants to come out and take these things away from you.
Do you have one of these in a restaurant you go to?  A place where you buy a cup and take as much soda as you want?  These are illegal in France as of this week. 

Final words to Stu Burguiere:
“They’ve taken something that a business has done to help their customer have a better experience, and because they think the customer is using it incorrectly . . . they're taking it away”
Typical stupid, progressive, nanny-state government.

Sunday, January 29, 2017

The Clearance Problem Has Been Cleared Up

A couple of days ago, I wrote about putting the table back on my G0704 mill and finding a problem with clearance around the oil tube to the Y-axis ballnut.  I concluded by saying, "Will the thinner tube lie lower and flatter in the cutout and be less susceptible to damage?  We'll find out."  The answer is it didn't.  The next morning, I could see that the tube had relaxed to the point where the table was hitting it.

The root cause is that the vertical edge on that part of the table goes over the oil fitting. The tubing is almost completely under the slide.  It's easy to see when the tube is off. 

I pulled the new bent tube and made another one out of a longer piece so I'd have more tube to play with.  After I heated the tube and flared it so it fits the oil fitting, I stuck the plastic tube from a spray can of air in it, held it over a heat gun and bent it a little past a right angle (plastic tube to emulate something like putting sand in a metal tube before you bend it - to keep the walls from collapsing/kinking). This was definitely a lower profile bend. I put that in place, but a straight edge sliding over it still rubbed on the tube. If I held the tube down with a finger tip, it seemed to clear, so I put a spot of RTV there and then taped it down with duct tape. It was still too high, so I stacked about 15 pounds of weights on top of it to clamp it as low as it gets. The tube said RTV takes a full 24 hours to cure, but after about 18, I took off the weights and tape to look at it.
That worked. You can see the gap between the tube and slide in this picture. The white thing is a scrap of business card that I measure at .010".  A .012 feeler gage slipped in there, but a .015 wouldn't.  Is that good enough?  My bet was that if I could be sure that it never went below .005, I'd feel good with it, but I didn't know. 

So I decided to machine away the part of the table that crosses and could rub on the tube. The idea is to cut away the underside of the table at about a 45 degree angle - 45 degrees at "eyeball accuracy" is good enough.  The table is about 28 inches long, so you see it requires cutting away a fairly large amount of cast iron.  I had thought of doing this before but concluded I'd need a mill at least the size of the G0704 to do it. A friend suggested an angle grinder. I simply hadn't thought of that because I just don't have experience with using a grinder. I bought one months ago for this project and then used my Sherline mill to do the cutting the grinder was intended for.
So I pulled the table off and rolled it outside on a dolly (it weighs more than 50, maybe 60 to 70 pounds).  I marked a line about 2/10 of an inch from the edge of the table along the full length of this edge and ground it to look smooth.  This gives you an idea of what the last few inches of the table looked like after cutting. 

It ended up going very quickly and came out remarkably smooth. Now I have plenty of clearance over that tube.  

You know the old saying, "when the only tool you have is a milling machine, every problem looks like a machining problem"  (or something approximately like that involving hammers and nails)?   When I thought about cutting back that edge at a 45 degree angle or so, I though of using a 45 degree cutter in a milling machine, or a straight cutter with the table on a fixture of some sort.  I simply never thought of the angle grinder.  Mind you, as I've said about knife making, after a few dozen silversmithing projects, I've come to believe I can do just about anything with a few hand files.  I could have done this with hand files and taken a week of labor or a few minutes with an angle grinder.  The angle grinder is the way to go!

Saturday, January 28, 2017

Gun Show Today

This weekend, there's a Military Expo and Gun Show going on just to the south of us in Vero Beach.  We've gone to that gunshow before but haven't been on one of these weekends when they do the Military Expo.

We didn't see as much of the Expo side of this as we might have, but there was a lot of military surplus for sale, dating back to the "usual" turn of the 20th century-vintage rifles like '03 Springfields and '98 Mausers.  Between the outdoors surplus sales and the indoor gun show, I saw more M1 carbines and M1 Garands than I've seen in one place before (I obviously haven't been to the CMP).  This included a Garand chambered in .308 and rebuilt on a garish laminated stock.

On the unexpected side I saw and got to play with ("coon finger" to use Tam's evocative phrase) a Ruger Precision Rifle, which I've been wanting to see for at least 18 months.  In fact, there were two of them there, one in .308 and one in 6.5 Creedmoor.  It really is an impressive rifle.  The one I played with was the 6.5 Creedmoor and was brand new, being offered by a dealer.  I didn't mess up the adjustments, at least not much, but was interested in the hardware and general fit and finish.  Excellent, as expected, with a great feel.  The quick release hardware was like those used on bikes, which I haven't seen on a gun before.  To be honest, I was a little surprised at its weight, although they do list it as a 10.7 lb rifle.  Guess that didn't work its way into my subconscious.  It was comfortably (25%) under MSRP, which was nice to see, but no, I didn't give it a new home.

I'd like to see comparisons between the RPR and the Savage BA Stealth, which appears to be designed as head-to-head competition with it. 

Those who follow Michael Bane's shows and especially his podcast know that he believes that PCCs (as he calls Pistol Caliber Carbines) are the next big thing.  We only saw one there (as three rifles at two sellers), and they were Hi-Point 9mm carbines.  Neither one of us has ever handled one of those before and Mrs. Graybeard surprised us both by really liking the feel of it.  Now Hi-Point, bless their hearts, doesn't exactly have the most sterling reputation, but we determined to go track down actual user feedback.  Our almost-neighbors up the road have very well known PCC, and they need to be considered as well.  On that subject, Bane writes:
The venerable Kel-Tec SUB-2000, available in 9mm or .40 S&W with magazines for multiple platforms and a low-ball price of $500, remains the first choice for a first pistol caliber carbine — if you can find one! GunBroker is your best bet.
Things I probably almost definitely would have bought if I found one: A decent 1911 for under $500; mostly to use as a model when I finally get to machine one.  A Savage Mark II in 22LR, especially if it was that model or on a good wood stock without the thumb hole stock.  A Ruger American Predator Rifle in 6mm Creedmoor.  None were found.  6mm Creedmoor?  When it was introduced, the RPR was available in .308, 6.5 Creedmoor and .243.  This year, they've dropped the .243 in favor of the slightly smaller 6mm.  If I look at this article, 6.5 and 6 are virtually identical, with a "perfect shoot" just 1% better with the 6.0.  The article says the 6mm Creedmoor does that with much less recoil, but at the cost of slightly less barrel life.  I could see going with 6 in a long distance rifle as long as I'm not trying to humanely hunt at those distances.

Feedback from those of you who actually shoot these combinations, or anything I've speculated on is always, always welcome.

 The Ruger Precision Rifle (RPR)

Friday, January 27, 2017

We Begin NASA's Worst Week

It's a peculiar coincidence that all NASA missions that ended in the crew being killed and vehicle destroyed occurred in the same calendar week, although separated by decades.

Today, January 27th, is the 50th anniversary of 1967's hellish demise of Apollo 1 and her crew, Gus Grissom, Roger Chaffee and Ed White during a pad test, not a flight.  In that article, Ars Technica interviews key men associated with the mission and provides, for the first time I've seen, the audio of the test.  In the early days of the space program, one of the larger than life names we came to all recognize was Chris Kraft, who had directed all of the Mercury flights and many of the Gemini missions and was widely recognized for this masterful control.
Half a century later, the painful memories remain. “I was on console the day it burned,” he explained, sitting in his second-floor den, just a few miles from the control center that now bears his name at Johnson Space Center.

“I heard their screaming voices in the cockpit of the spacecraft,” Kraft recounted. “I heard them scream that they were on fire. I heard them scream get me out of here. And then there was dead silence on the pad. Within minutes we knew they were dead, and we were in deep, serious trouble. Nobody really said anything for 15 minutes, until they got the hatch open. We were sitting there, waiting for them to say what we knew they were going to say.”
There was plenty of blame to go around—for North American, for flight control in Houston, for technicians at Cape Canaveral, for Washington DC and its political pressure on the schedule and its increasingly bureaucratic approach to spaceflight. The reality is that the spacecraft was not flyable. It had too many faults. Had the Apollo 1 fire not occurred, it’s likely that additional problems would have delayed the launch.

“Unless the fire had happened, I think it’s very doubtful that we would have ever landed on the Moon,” Kraft said. “And I know damned well we wouldn’t have gotten there during the 1960s. There were just too many things wrong. Too many management problems, too many people problems, and too many hardware problems across the whole program.”
The ARS article is worth your time to read. 

Tomorrow, is the anniversary of the Space Shuttle Challenger disaster.  Shuttle Challenger was destroyed on January 28, 1986 a mere 73 seconds into mission 51-L, as a flaw in the starboard solid rocket booster allowed a secondary flame to burn through supports and cause the external tank to explode.  It was the kind of cold day that we haven't had here in some years.  It has been reported that it was between 20 and 26 around the area on the morning of the launch and the O-rings used to seal the segments of the stackable solid rocket boosters were too cold to seal.  Launch wasn't until nearly noon and it had warmed somewhat, but the shuttle had never been launched at temperatures below 40 before this.  Richard Feynman famously demonstrated that cold was likely the cause during the televised Rogers Commission meetings, dropping a section of O ring compressed by a C-clamp into his iced water and noting that it had lost its resilience at that temperature.

There's plenty of evidence that the crew of Challenger survived the explosion.  The crew cabin was specifically designed to be used as an escape pod, but after most of the design work, NASA decided to drop the other requirements to save weight.  The recovered cabin had clear evidence of activity: oxygen bottles being turned on, switches that require a few steps to activate being flipped.  It's doubtful they survived the impact with the ocean and some believe they passed out due to hypoxia before that. 

Finally, at the end of this worst week, Shuttle Columbia, the oldest surviving shuttle flying as mission STS-107, broke up on re-entry on February 1, 2003 scattering wreckage over the central southern tier of the country with most debris along the Texas/Louisiana line.  As details emerged about the flight, it turns out that Columbia and everyone on board had been sentenced to death at launch - they just didn't know it.  A chunk of foam had broken off the external tank during liftoff and hit the left wing's carbon composite leading edge, punching a hole in it.  There was no way a shuttle could reenter without exposing that wing to conditions that would destroy it.  They were either going to die on reentry or sit up there and run out of food, water and air.   During reentry, hot plasma worked its way into that hole, through the structure of the wing, burning through piece after piece, sensor after sensor, until the wing tore off the shuttle and tore the vehicle apart.  Local lore on this one is that the original foam recipe was changed due to environmental regulations, causing them to switch to a foam that didn't adhere to the tank or stand up to abuse as well. 

There's film from inside Columbia until the moment the vehicle is ripped apart by the aerodynamic forces.  I suspect the forces ripped apart their bodies just as fast.  

January 27 to February 1 is 6 days.  Not quite a full week.

On a personal note, I remember them all.  I was a kid living in Miami when Apollo 1 burned.  I was living here and watched Challenger live on satellite TV at work.  Instead of going outside to watch it as I always did, I watched it on NASA Select.  Mrs. Graybeard was working on the unmanned side on the Cape, next door to the facility that refurbished the SRB's between flights, and was outside watching the launch.  It took quite a while for the shock to ease up.  I saw those spreading contrails everywhere for a long time.  Columbia happened when it was feeling routine again.  Mom had fallen and was in the hospital; we were preparing to go down to South Florida to visit and I was watching the TV waiting to hear the double sonic booms shake the house as they always did.  

When this blog started, one of my regular reads was Dr. Sanity, a flight surgeon for NASA and board-certified psychiatrist.  She was Crew Surgeon for Challenger and has left posted a haunting recollection of the mission although her blog hasn't been updated in over four years.  I conclude with a quote from that post:
I remember the Challenger and her crew frequently and with love. They are a part of me now. All of them represent the best within the American spirit, and always will. Since that day in 1986, I have come to see NASA as one of the greatest impediments to the Dream of space exploration; but I have never given up the Dream itself. Nor have I forgotten any of the pioneers who have died in the service of that Dream. Some day we humans will leave this small planet and joyfully play in all the corners of the cosmos.

I eagerly look forward to it.
The failure reports and investigations of all three of these disasters center on the same things: the problems with NASA's way of doing things.  Tending to rely on "well, it worked last time" when dealing with dangerous situations, or leaning too much toward, "schedule is king"; gambling that someone else would be the one blamed for delaying a mission.  Spaceflight is inherently very risky, so some risk taking is inevitable, but NASA had taken stupid risks too often.  People playing Russian Roulette can say, "well, it worked last time", but that doesn't mean playing has reduced their odds of losing. 

"I have come to see NASA as one of the greatest impediments to the Dream of space exploration; but I have never given up the Dream itself."  We're in complete agreement. 

Wednesday, January 25, 2017

Small Steps Forward...

Small steps forward are better than small steps backward or standing still. 

The work on my CNC conversion continues.  After getting the Z-axis moving, I went to look at how to get the oil fittings hooked up and found to my horror that I had installed the ballnut pointing the wrong way.  There's a hole in the top of the Z-column that allows feeding in the oil tube, and it was on the opposite side from the fitting.  That meant zero chance of getting a tube onto the fitting through the hole, or doing it without taking the column apart.  After some agonizing over that, I took the motor and mount back off, then pulled the ballscrew and nut, finally putting the oil fitting into the place it goes.  That was a step backward.  It doesn't fit. 
This looks fine, right? I mean except for the white fitting being overexposed. If you look in the holes in the ballnut facing you, you'll see metal, not the threaded holes that they are supposed to line up with.  If I rotate the ballnut to get them to line up, the fitting hits the side wall of the casting it's in. 

I'm still researching ways to get around that.  I really want to minimize the amount of doing everything several times that I'm trapped in, and I'm especially concerned about anything that would make me pull the ballnut off its screw and involve a potential second Ballnut Removal Tool fiasco.  So while I think about this problem, I moved on to build the oil distribution system for the XY table, so that I can put that back together.  This required some tubing adapters and some 1/4" OD tubing.  I had to order the adapters, but the tubing itself was available in town.  It took a couple of days to get everything here and then minutes to finish the distribution system. 

In this view, the upper right is a Tee connector.  The hose from the oil pump will go into another Tee before this one: one of its outputs will go to the Tee visible here while the other output will go up the Z column to oil that and to another Tee up there.   
Getting the tubing completed means there's nothing to prevent me putting the table back on and getting both X and Y moving under CNC control.  The table is the heaviest of the pieces I've been slinging around and getting it into the chip tray definitely made a few body parts complain, but nothing seems injured.  While I was playing with the table, it just didn't feel right.  Investigation led to me discover another step backward.
The table was sitting on the 1/4" tubing, rocking back and forth.  I could bend the tube closer to the fitting, but examination after pulling the tubing off showed that the edge of that vertical wall is over the middle of the fitting.  Maybe that part of my table is wider than in earlier models, but I haven't heard of this problem before.  I think that with the table sticking that far over the fitting, the table is always going to rub on the tube.  Which will probably lead to failure "sooner rather than later".  After thinking about this for a while, I decided to see if I could heat the smaller diameter tubing I have and stretch it to fit over the fitting.  It worked.  The smaller tube bends closer to the fitting and pulls out of the way easier. 

With that at least temporarily resolved, I could slide the table around, put the non-motorized (left) side's end cap back on, and then look at putting the motor on.  Will the thinner tube lie lower and flatter in the cutout and be less susceptible to damage?  We'll find out.
In the middle front,you see the black motor, followed by the blue angle stock motor bracket and the rectangular blue Y axis extension, then the cross slide with the X table on it.  Along with a mess of tools and stuff.  This is the first time the base has had the table and cross slide both mounted on it in I-don't-know-how-long. 

With some luck, I should be able to get the X-axis motor mounted tomorrow and then see if I can get this whole thing to move under CNC control.  It should. 

Tuesday, January 24, 2017

Samsung: It Wasn't Our Design, It Was the Batteries

Since I wrote two weeks ago about an independent consulting group's report laying the blame for the burning Samsung Galaxy Note 7 phones on Samsung's mechanical design, I feel that fair reporting says I should let Samsung tell their side of the story.  Samsung held a press conference Monday, the results of which were published today in EE Times, and while they say it was the batteries fault, their argument is reminiscent of the conclusions of the independent consultant Instrumental covered two weeks ago.  
...Samsung investigators uncovered two separate faults with the two batteries.

Samsung pinpointed the handset design caused overheating of “Battery A,” which was used in the Note 7 model first recalled. “Battery B,” deployed in the second recalled Note 7 model, is now identified with a manufacturing defect.

Although the Korean giant refrained from naming the battery suppliers, it is known that Battery A was manufactured by Samsung affiliate SDI. China’s Amperex Technology, a subsidiary of Japan’s TDK, provided Battery B for the Note 7.  [Bold added:  SiG]
In the case of battery A, Samsung says the battery didn't fit properly in its enclosure and admitted to a design problem here, causing the internal plates in the "jelly roll" design to short.  This, in turn led to causing the devices to overheat and catch fire.
This seems to me hard to blame on the battery vendor.  If Samsung forced the battery in to a corner that was too rounded, either the corner was designed incorrectly or built and used incorrectly.

In the case of Battery B, Samsung points out problems internal to the battery pack.  This is clearly the battery vendor's (Amperex's) problem.
Samsung ruled out any other problems with the phone.  Speculation at the time was that processor-controlled charging might have been the cause, since they were putting a larger capacity battery in the phone and attempting to charge it faster.
Samsung said that the company has implemented a broad range of internal quality and safety processes to “further enhance product safety including additional protocols such as the multi-layer safety measures and 8-Point Battery Safety Check.” The company has also formed “a Battery Advisory Group of external advisers, academic and research experts to ensure it maintains a clear and objective perspective on battery safety and innovation.”

However, the company made no reference to Samsung’s corporate culture. Reputedly, Samsung engineers cope constantly with a high demand environment, pressured to meet such overambitious goals as larger battery capacity and faster charging speed. Many industry observers noted last fall that Samsung’s high-pressure corporate culture prompted the hurried release, and subsequent recall of the replacement Galaxy Note 7 devices.
This was a large press conference in Seoul on Monday, complete with Koh Dong-jin, president of Samsung’s mobile communications business, bowing and apologizing for the fiasco.  Samsung made a big point out of saying they had hired external experts, the Underwriter's Laboratory and Exponent, to help.  From my standpoint, I don't know how helpful either one of those would be but apparently Samsung respects them.  The only time I ever worked in a place that got UL approvals, their only concern was the AC powerline until it went into the low voltage supplies.  I don't know how good they are at Li-ion battery problems.  I never worked around Exponent, but they don't have the long history and name recognition that UL has. 

Samsung's report doesn't address the thickness issue that Instrumental addressed in their report, covered two weeks ago.  Samsung does address the lack of space around the battery's edges and seems to implicate lack of space in the corner, but Instrumental's observation that their two-month old unit had no space above the battery at all seems to indicate a need for a thicker phone (or less battery capacity).  It's worth pointing out that when a company contracts for a battery it isn't like the way you or I walk into a store and buy one; the buyer creates a procurement specification and then is responsible for verifying what they bought actually meets the specification.  It's a mind-boggling understatement for me to say that a lot of effort goes into this.  It usually entails a lot a meetings, and to qualify a new product, entails extensive face-to-face meetings and testing.  Samsung said it did not plan to take legal action and that it accepted responsibility for asking the suppliers to meet certain specifications.

Monday, January 23, 2017

NHTSA Lets Tesla Off the Hook

We've written in this space before about a Tesla "autonomous" car that mistook a truck for the sky and got its driver killed last May.  The National Highway Traffic Safety Administration released the results of its investigation into the accident last Thursday (1/19) (pdf warning) finding no defects in Tesla’s Automatic Emergency Braking (AEB) and Autopilot systems.  To quote from that EE Times piece by correspondent Junko Yoshida:
Definitely, Tesla is exonerated.

Did NHTSA let Tesla off the hook too easily? Absolutely.

What lessons or guidance, if any, did NHTSA’s findings offer to the rest of the automotive industry? Very little.
For technical analysis, Yoshida went to Mike Demler of the Linley Group, a  technology analysis and consulting company in the electronics industry.  Demler had a lot to say, and none of it terribly flattering.  He said NHTSA essentially had already decided the case by other decisions they've made along the way to this.
“The critical issue here is that the Tesla fatality involved the combination of AEB and Autopilot,” said Demler. As the report shows, NHTSA “already accepts that AEB reduces accidents, and that the Tesla AEB performed according to the current state-of-the-art,” he explained. “But what happens when you combine AEB with Autopilot?”

He noted, “It would be different if Autopilot just added lane-centering to Adaptive Cruise Control (ACC) and AEB. [If that’s the case], Autopilot’s primary function isn’t safety, but it’s convenience.”
But it didn't just involve the routine lane-centering of Autopilot, which is like cruise control for steering: "keep it between the dashed lines".  This accident involved a truck turning left in front of the car and the Tesla's inability to tell a truck from the sky.  I argue that once a child learns the words for truck and sky, age 3?, no child is going to make that mistake, but the car's decision cost the life of the Tesla's owner/driver.  Furthermore, NHTSA's investigation said that truck should have been "observable" for 7 full seconds before the crash, time in which the driver should have been able to apply brakes and take control away from the car - if he knew he had to.  NHTSA says:
ODI (the Office of Defects Investigation)’s analysis of Tesla’s AEB system finds that 1) the system is designed to avoid or mitigate rear-end collisions; 2) the system’s capabilities are in-line with industry state of the art for AEB performance through MY 2016; and 3) braking for crossing path collisions, such as that present in the Florida fatal crash, are outside the expected performance capabilities of the system.
The question is whether or not the driver knew to not let the system drive in that circumstance, and if the car tried to notify him at some point.

There really is a lot to this story and it's worth your time.  Realize that in absolving Tesla of responsibility in this accident, NHTSA is implicitly encouraging more use of systems like this that are vulnerable in the event of a crossing vehicle.  NHTSA is saying Tesla can't be held liable in a lawsuit; the problem was the driver.  In saying NHTSA “already accepts that AEB reduces accidents, and that the Tesla AEB performed according to the current state-of-the-art,” they're committing to more cars with AEB systems.  Furthermore, since we all know agencies like NHTSA work at a snail's pace, Tesla was able to end-run around them by updating the software in the car "over the air" before they completed their investigation and NHTSA apparently took Tesla's story uncritically. 

Closing words to Mike Demler quoted in EE Times:
“NHTSA was obviously careful to apply a very narrow focus to this investigation,” Demler observed. “I’d say it was about 90% AEB, and only 10% Autopilot.”

NHTSA “could have dug into Autopilot more, at least as a warning to other manufacturers building similar systems,” he noted. In summary what they said was “we accept Tesla’s descriptions of how Autopilot works, the warnings they provide, and the fix they implemented.”

That’s pretty weak, Demler added.

The Florida Highway Patrol accident report on the May fatality.

Sunday, January 22, 2017

Oh, The Humanity!

No wieners were harmed in the accident, that I can tell.  This was on December 15th, although the location is gone from my notes. 

Strange as it may be to see the Oscar Mayer wienermobile here, we actually saw it in person once.  It was in May of '06 at Carlsbad Caverns in New Mexico.  Here's the wiener in happier, or at least warmer, days. 

Saturday, January 21, 2017

Silencers, Sound Levels, Decibels, and How to Know

A few days ago, I posted a little on the Hearing Protection Act.  If you've paid attention to the SHOT show coverage, you've seen people talking about not assuming it's going to pass this year but we're likely to get it in the not-too-distant future.

Coincidentally, a friend who doesn't follow my blog sent me a link to the National Institute of Occupational Safety and Health, NIOSH, telling about a free iPhone app they provide that will use your phone's microphone to measure noise levels in the standard dBA format.  Naturally I went to the iTunes store and grabbed a copy to play with.
(NIOSH photo)  The app is called NIOSH SLM (sound level meter) and is intended for checking sound levels in an occupational setting - this is NIOSH's domain, after all - so they intend for folks to survey their work area and then get more accurate readings if needed.

SLM runs only on the iPhone and they say there's no android version in development.  Android discrimination?  There's a very logical reason for them to go to iPhones, even if they are going to add android later.  The iPhone is one product with known standards for how the microphone works, the levels it responds to and all the nitty gritty details that are necessary to do this.  Android is actually an open source platform and there are several phones or tablets out at any time.  Different manufacturers use different hardware that may or may not respond the same way.  If Apple changes the hardware in the phone, it's going to comply with the same specifications as earlier phones, as long as they want to keep backwards compatibility.

NIOSH claims that with an external microphone and calibration it will meet the accuracy of higher end instruments, but as it comes with the iPhone it's accurate to "within +/- 2 dB "of a type 1 sound level meter", defined as "Precision" for use in the field or laboratory.  That's pretty amazing.  Like many (not all) audio measurements, the results are expressed as dBA, where A is frequency response curve, sometimes called "A weighting".  The A weighting is supposed to match the response of the human ear to audio frequencies and there are several weighting curves.  A site with a lot of handy information is Noise Help, who provides this handy chart
As a guide for when hearing protection is needed you can combine that table with one that the NIOSH website provides.  This is the permissible exposure to sound powers that are considered damaging to hearing.  As a rule of thumb, 85 dBA is around where most people feel the need to raise their voice in a conversation.  If you spend your day having to raise your voice to be heard over something that's running, you probably need to be wearing hearing protection. 
Time-Weighted Average (TWA)Time to reach 100% noise dose
85 dB(A) 8 hours
88 dB(A) 4 hours
91 dB(A) 2 hours
94 dB(A) 60 minutes
97 dB(A) 30 minutes
100 dB(A) 15 minutes
Notice that for a 3 dB increase or decrease in the dBA level the time halves or doubles respectively.  If you look at the right column, you'll see a table saw comes in at 105 dBA.  The chart stops at 100, so what's safe?  103 dBA would cut that to 7-1/2 minutes and 106 dBa would cut it to 3-3/4 minutes (3:45).  You shouldn't run a table saw for more than that in a day without hearing protection.

Impulse noise, like that from a gun, is different and seems to affect hearing differently, causing a loss of high frequency hearing faster than continuous noise does.   Since noise levels for everything past a .22 rifle (130 dBA) is in the 150 to 155 range, hearing protection is absolutely required - but you knew that.  If putting a suppressor on a gun drops 155 to below 130, by everything I can read, you should still wear hearing pro. I'm unable to find anything that says that suppressors do anything more for hearing than simply changing the dBA level of the shot; that is, I see nothing that shows that modifying the shape of the noise impulse helps.  You will read that some Fed.gov agency said that if the crack of the gunshot impulse noise is less than 140 dBA that hearing protection is not needed. 

How does the App work?  You can simply open it up, and there are help screens accessed by tapping on "?" on the page.  Sitting here typing, with the phone's microphone pointed at my keyboard, typing puts the sound levels into the mid 50s to over 60dBA, which is pretty quiet.  When I stop typing, the noise level drops to the around 40.  When the air conditioner starts, that goes up by 3 dB.  Proximity to the microphone is important, so they say the SLM is accurate when it's a meter away (call it one yard) from the source.  The display responds to things like hitting one key on the keyboard, but whether it will give accurate readings on gunshots is a question that has to wait.  

I Tried It So You Don't Have To

I searched WhiteHouse.gov for "climate change"

Just a mention of Mamie Eisenhower moving to San Antonio for the milder climate. 

Combine this with Gunmart.com finding and it's like the storm clouds are clearing out.

Friday, January 20, 2017

Eight Years of Fundamental Transformation and Some Thoughts

I've heard a couple of things about the Trump administration that I can't verify, but that are being reported.  The first is that at the stroke of noon today, the White House web pages dealing with climate change went away.  The second is that he has asked for (ordered?) a ban on new regulations.  I find both of these tremendously encouraging. 

A quick check over at Regulations.gov shows that in the last 90 days a total of 6313 regulations have been posted.  As a rule of thumb, that's a little higher than typical, but only about 5% high.  Based on looking at that site at random times since the end of 2011, I believe the typical number is about 6000 in 90 days. 

Let's play with numbers a little. In 8 years, there were 32 three month periods (that's roughly 90 days). That's 192,000 regulations that went through the regulations.gov website and their processes.  If you read the website, you'll see that not everything they handle is strictly a new regulation in the sense you're thinking of.  Many are tweaks to existing programs and regulations, but every one of them still costs money.  For example, there's currently a pair of regulations open for comment that address "standards grades for walnuts and shelled walnuts" and another for "standards for grades for onions and frozen onions".  Certainly companies involved in the walnut or onion markets are going to care about these a lot, but why is the Fed.gov involved? 

Moving on, today is a good day to do a retrospective of the greatest gun salesman in history, EX president Obama.  Through last October, about 12 weeks ago. 
The increasing trend in sales has been going on for as long as this dataset, since '04, but the spikes during the Obama years are pretty amazing.  You see things like the lowest sales month in 2012 was higher than the biggest sales spike through 2008.  

Finally, I have to admit that Obama was among the things that changed me.  It's a truism that personal growth tends to happen during times when we're under duress, not when we're comfortable.  If life is a series of mountain and valley experiences, the growth happens in the valleys not on the peaks.   Eight years ago was essentially when Mrs. Graybeard and I got involved in shooting sports.  When we "woke up".  I started this blog just under seven years ago.  I had started to educate myself on monetary policies and many other regular topics here long before Obama; actually in the early years of the W.  Obama just brought the pressure of attacking and transforming everything I thought I knew that was right.  I believe that Glenn Beck says something similar, saying "Obama made me a better man".  With that I disagree.  To the extent that I'm a better man, Obama didn't build that; I did.  I made myself a better man in response to Obama.  In much the same way that an oyster responds to a grain of sand. 

Yo!  Is dat poetic enough for youze?

Repeat After Me

Former President Barack Obama 


The long national nightmare is over.

Thursday, January 19, 2017

The Amish High Tech Buggies

Amish high tech?  A contradiction in terms?

A friend sent me a link to this story on Popular Mechanics about the migration of technology into Amish buggies.
Despite what you heard, the Amish aren't against technology. Communities adopt new gadgets such as fax machines and business-use cell phones all the time—so long as the local church approves each one ahead of time, determining that it won't drastically change their way of life.

So it is with the Amish horse-drawn buggy. You might have thought the technology inside this 1800s method of transportation stopped progressing right around then. Instead, buggy tech keeps advancing, and buggy makers have become electricians and metalworkers to build in all the new tech you can't see under the traditional black paint.
Central Florida is a long way from Amish country, and I've never met any Amish people, so I'm sure I'm just full of stereotypes that are all wrong.  Consequently, I found the article interesting and think it's worth your time to read the whole thing.  As I always do, let me drop some teasers here to encourage you.
Even if you skip luxury options such as a propane-powered heater, cupholders, and speedometer, a buggy is an expensive thing.
Buggy brakes are automotive-style, non-powered drum or disc brakes mounted to two wheels. When a driver wants to stop, he or she halts the horse using the reins and halts the buggy by stepping on the brake pedal so that it doesn't run into the horse.
"Back in the '60s, a local Amish man started going through junkyards and getting the old seven-inch VW brakes," our builder says, "salvaging them, repairing them, and cleaning them up, and retrofitting them to buggies. After a while he started getting good castings made. Now all the buggy brakes are manufactured by buggy shops."
"Ninety-nine percent of buggies are built with a dash—a console on the front panel—and in that switch box is all the switches you need," says our builder. "We have headlights, taillights, interior lights, and a turn signal switch."
To power these lights, batteries are all over the place.
"Average cost of a buggy is, I'm gonna say, $8,000," says our builder. Families usually have several types at once, for different uses, and each one they buy outright with cash. "We actually looked into doing financing through the banks," he says, "but we don't have titles for buggies, so the banks are squeamish about it." If somebody needs it, though, builders will finance them a buggy without the banks.

"A lot of people will get 20 or 30 years out of a buggy before they do any major rebuilding of it. There's a strong demand for good used buggies because of youth. Most people will buy their 16-year-old son a horse, a harness, and a used buggy. And then we have people who trade in their buggy every five to eight years. It's like the mainstream world. A lot of these buggies will be running 40 or 50 years, rebuilt several times."
An Amish family buggy (Popular Mechanics/Getty Images).  You'll note that in addition to the large slow vehicle warning triangle, there are red and yellow LEDs on both sides of the buggy's rear, and on the driver's side a large rear view mirror with what might be a headlight just below it.  This is a low end buggy compared to others pictured in the article.

Wednesday, January 18, 2017

The Hearing Protection Act

I think that of the stupid and illogical restrictions passed in the National Firearms Act of 1934, the most illogical is the restrictions on silencers, which obviously aren't even firearms.  It's a silly requirement that imposes a $200 tax that was crippling when it was enacted, but has dropped in impact as our currency is inflated away.  In 1934, $200 was many times the cost of a gun; today, $200 is close to the price of the lowest cost guns but a fraction of the cost of higher end handguns.  Today, the application process and delays seem to be the most significant hindrance to widespread use of silencers.  Hopefully, the Hearing Protection Act can remove those false hardships. 

Hat tip to No Layers - Only Guns and Money for the heads' up warning he posted about the campaign against the Act starting in earnest.  He reports receiving the following email:
Mark Kelly, of course, is Gabby Giffords' husband, "affectionately" known as Space Cowboy.

The problems with this, of course, only start with the fact that while it's technically correct to say "silencers do suppress sound and light", that's what they're designed to do, the rest of the email is just the usual fear mongering.  They don't back up the claim that silencers are attractive to criminals, and they don't describe the actual changes silencers cause, which while helpful are actually pretty minimal.  They're appealing to the ignorant whose only knowledge of silencers is from far too many movies that show a silencer reducing the roughly 160 dBa sound of a .45 handgun down to a soft, puffing "pfft" sound.  In reality, instead of the 80 dB noise reduction that movie sound implies the actual reduction is around 30 dB or what your typical hearing protection provides, which reduces the sound of a .45 cal handgun down to a loud blast on a trumpet or a loud passage in a stadium rock concert. Yeah, it's quieter but it's still pretty darned loud.

Put it this way: it reduces the sound out of a .45 handgun to the sound of a .22 rifle.  I think everyone still wears ear protection around .22 rifles today. 

John Richardson writing at No Lawyers puts it this way:
Having reported on hundreds of defensive gun uses on the Polite Society Podcast I have yet to come across mention of a criminal having a suppressor in his or her possession while committing an assault, robbery, home invasion, or murder. Indeed, more often than not, these miscreants use the loud sound of a firearm discharge to attempt to cow their victims.
The references to the ebil debil "gun lobby" and "corporations who manufacture and sell firearm silencers" tell you what they're really all about: just restricting the rights of gun owners for no valid reason, and thinking we're all just brain dead zombies who do whatever the "gun lobby" or double un-good NRA tell us to do. 

Disclaimer and technical tangent: after a career in RF engineering, decibels are second nature to me, and while guys are fussing and "dB chasing" in silencers, making a huge deal over differences of a single digit in noise reduction, like from 31 to 32 dB, and companies are selling different models by stating attenuation to tenths of a dB, It Doesn't Matter.  Audio has a lot of counterintuitive stuff to it, and one of them is that while the dB scales that audio guys use correlates with Sound Pressure Level and other lab-type measurements, how loud a sound is perceived to be follows different rules.  You're entering the field of pyschoacoustics, and it's filled with all sorts of unexpected things.  For one, the perceived loudness of a sound depends on its frequency.  Another, while the difference in measured sound pressure doubles for a 3 dB increase in sound level, if you give someone a volume control and tell them to increase the power until the sound is twice as loud, they don't increase it 3 dB, they increase it closer to 10 dB.  In other words, if you're shopping for a silencer and they tell you one is good for 131.3 dB and another is good for 130.8 dB, no one will ever tell them apart in use. 

Tuesday, January 17, 2017

Before It Could Move

On Friday, I wrote about setting up to tear down the G0704.  And on it went. 
I cut out the marked square I showed, 1-1/4 on a side and cleaned it up.  I cut it out by drilling a lot of holes, using a 1/4" bit and an AC powered drill.  I started out with my battery powered drill but it was just obviously weak for the task and I thought I'd try the "big" one.  Night and day difference, but it has a label rating of 1-1/4 HP while the battery powered one never mentions power.  I cut the web out between the holes with both a battery powered reciprocating saw along the sides where the blade fit, then switched over to an AC powered jig saw which also made short work of the sawing.  There was some really irregular looking junk in the casting on the back of that channel you see (out of picture at top center) that I thought might limit the motion of the ballnut and table, so I cleaned that up with a grinding bit on my battery powered drill. 

The next step was to take the motor and headstock off.  This ends up weighing 50-ish pounds (rough guess).  I found a guy on YouTube (N1BPD) who had a video of taking the motor and Z column off and then another that showed him building it back up
Which leaves the base and column as the only pieces on the tool cabinet/stand.
On to taking off the column and here's where I hit a dead end.  There are four large socket head bolts in the base of the Z column holding that cast iron in place.  They take a 10mm Allen key, and as luck would have it, I had two options: a ratchet set from Sears with the novel feature that most of the sockets will pass any length bolt through them, and a nice, tool steel, Allen wrench set's 10mm key.  Two of the bolts were moveable and I got them loose, but the other too resisted everything I could do to them.  At one point, I actually tried to stand on that 10mm key.  Since it was Sunday, I said Uncle and went to think about it and figure out how much I was going to have to pay to break those two bolts loose, while watching the Packers/Cowboys playoff game.

It ended up being fairly cheap, because Mrs. Graybeard convinced me to try an adapter to mount the hex key socket on my 1/2" drive breaker bar.  Thankfully, that worked and I was able to pull the Z column.  This was right after I had watched the video where N1BPD built up his Z-axis and got it running.  I decided I had all the parts and had been basically ready to do the modifications on this for quite a while, so why not do it and get the system running?
This pic was while putting the Z-axis ballnut mount in place.  I've written a lot about this part.  The motor mount and standoffs were the parts I made for the original approach I was taking, before I switched to the ballscrew approach last April (I think).  I think I made them about a year ago.
If you look carefully at this picture, you'll see something strange.  There's a 1/4-20 nut on each of the round, threaded standoffs.  When I first built this, the motor quickly jammed and during troubleshooting, I realized the motor wanted to be about an eighth inch farther away than the standoffs allow.  A quick check of the relevant drawing said they were supposed to be 2.000 inches long, +/- .005, and they were.  Rather than make new standoffs, this was a quick fix.  It passes a 10-32 screw to mount the motor and looks neater than a stack of washers.
Tonight, the base is remounted in my wooden "boat"; the chip tray I built last summer and that has been sitting along the wall while I got to this point.  I had always envisioned trying to hold the full mill, or parts of it, over the chip tray with a crane and struggling to get it in position.  Broken down this far, it's just a 50 pound-ish hunk of cast iron to set down in the tray, finagle into place and bolt down.  I could use to seal the base so that cooling fluid can't run under it.

It Moves!

I took a slight detour in my continuing CNC conversion project today.  I decided that since I had the Z-axis apart and on the bench, I'd put in the new motion control hardware: ballnut, mount, ballscrew, and motor mount.  All the stuff I've been working on for a long time.

You'll notice there's a handwheel on the motor.  That's a spare I keep around from the Sherline and use on occasion with it.  I used it here to help line up the motors and mounts while getting everything running.  It's already off the machine.  Everything is a temporary setup, including LinuxCNC, which is using my Sherline configuration file. 

I could have left this for later, after the X/Y table is done, but it's nice to see real progress like this.  Because motion!

Monday, January 16, 2017

That Whole "Boomers Screwed the Millennials " Myth

Rage is all the hotness these days; everyone has to rage against someone or something whether it's correct or logical or anything else.  It's like demanding safe spaces; everybody's doing it.  For the last 7 years of this blog, I've occasionally taken aim at those who rage against "income inequality" (there better be inequality!) and rage against the economy while empowering the very groups that cause the problems they're complaining about.  A few times, I've taken aim at those who blame all the troubles of the world on the boomers (who are their parents or grandparents) and show how those arguments are simply attempts to divide us against ourselves. 

The latest is one that's from CNBC and getting some traction around.  "Millennials are Falling Behind Their Boomer Parents".  The piece opens:
With a median household income of $40,581, millennials earn 20 percent less than boomers did at the same stage of life, despite being better educated, according to a new analysis of Federal Reserve data by the advocacy group Young Invincibles.

The analysis being released Friday gives concrete details about a troubling generational divide that helps to explain much of the anxiety that defined the 2016 election. Millennials have half the net worth of boomers. Their home ownership rate is lower, while their student debt is drastically higher.
The analysis of the Fed data shows the extent of the decline. It compared 25 to 34 year-olds in 2013, the most recent year available, to the same age group in 1989 after adjusting for inflation.
The glaring problem with this comparison is that it leaves out a very important comparison: how are those boomers who were 25 to 34 in 1989 doing today compared to how they were doing in 1989?  Despite years of rising prices, wages have been stagnant since the mid '70s, a few years after the gold standard was dropped.  The typical American man earns 29% less today than he did 40 years ago.  More to the point of the article the typical man working today is doing worse than he was in 1989.  The problem isn't that millennials are doing poorly compared to baby boomers in 1989, the problem is that the typical worker is doing poorly compared to 1989 no matter what generation they're from.

I was careful not to say everyone is doing poorly compared to 1989.  The high skill/high demand occupations, the top 10% of wager earners, are making more money.  These aren't all stock brokers and bankers; engineers, managers, doctors, and high-tech entrepreneurs are in this group.  Bonner and Partners provide this graphic
Note the very different time scales on the horizontal axes.  The top chart is only the right half of the bottom chart's time scale.

Despite all this, the biggest "sin of omission" in the CNBC article is in not explaining why this situation is happening; and the reason they won't go there is obvious.  The economic problems here, the so-called "income inequality" problems, are the result of the big government  and central bank manipulations of the economy.  The problems are the result of the debt-based economy we live in, and CNBC is behind Keynesian interventions.  No, it's easier for them to imply that the country is buckling under the weight of the baby boomers, and it's all those old peoples' fault.  It's easier for them to imply those old people are sucking up all the money in the economy and keeping it from being paid to those deserving millennials.  Those old boomers should just die and get out of the way.

The longer the debt bubble keeps growing, the more likely something bad is going to happen.  Nobody can tell you the date and time, but with the national debt virtually at $20 Trillion and another $200 Trillion in other commitments, it doesn't seem the confidence game can be kept up indefinitely.  When people "rage against the machine", they should rage against the right machine, the Fed.gov spending policies and the Federal Reserve Bank, not their parents. 

Sunday, January 15, 2017

SpaceX Nails Return to Flight, Booster Return

SpaceX had a successful return to flight launch from Vandenberg Air Force Base yesterday, putting 10 Iridium satellites into orbit.  In addition, they had a successful recovery of the 1st stage on their drone barge "Just Read the Instructions", hitting the center of the target with the live video feed working completely through the landing, for the first time.  This is the first time they've successfully landed a booster launched from Vandy.

SpaceX is quick to point out the most important part of the mission is that they delivered for their customer, and from a business sense that's absolutely right. It's just us space geeks who follow the ability to recover the boosters as a way to cut costs, and cutting costs is the key to bringing spaceflight to full commercial use.  How common would air travel be if we had to throw away the planes after one use?

Readers will recall that SpaceX had a highly unusual accident during a "routine" test on the pad on September 1st and has been grounded since then.  It was a tough problem to troubleshoot, but armed with just 93 milliseconds worth of data before the explosion, engineers isolated the problem to the rupture of a high pressure helium tank by late September, and then spent another couple of months verifying that with some creative testing.
The Sept. 1, 2016 explosion, which occurred during a routine pre-launch test at Cape Canaveral, initially puzzled SpaceX; about a week later, Musk described the incident as the "most difficult and complex failure" in the company's history. But technicians and engineers eventually traced the cause to the failure of a high-pressure helium vessel inside the Falcon 9's second-stage liquid-oxygen tank.

SpaceX announced earlier this month that it had wrapped up its investigation of the Sept. 1 accident. The Federal Aviation Administration accepted the results of the inquiry and granted SpaceX a license that covers all seven launches required to orbit the 70 Iridium-NEXT satellites.
The Falcon 9 launch system has been changing over to a colder liquid oxygen than other boosters use, called densified liquid oxygen (pdf warning - Master's Thesis).  Liquid oxygen boils at 90.2 degrees Kelvin (-297.3 F).  SpaceX is switching to a colder, denser liquid oxygen at about 65 K to improve engine efficiency.  Like other launch vehicles in the industry, SpaceX uses Composite-Overwrapped Pressure Vessels to contain the helium, and submerges them in the liquid oxygen.  The difference is that SpaceX is the first to use the COPV helium tanks in a liquid oxygen that's substantially colder than the 90 degree Kelvin boiling point.
The previous iteration of the Falcon 9 used Liquid Oxygen at boiling point temperature and began loading its tanks over three hours ahead of launch – permitting the COPVs to be fully chilled prior to applying high pressures. Falcon 9 FT enters LOX load on the second stage with just 19.5 minutes on the countdown clock followed by Helium load just over 13 minutes prior to launch – an aggressive tanking sequence unprecedented in the space launch business.
In a way, this sort of process/handling issue is the best thing that could have happened to SpaceX - ignoring the loss of vehicle, customer's payload, and all the costs.  It's easy to change the rates and times at which propellants are loaded.  It's even relatively easy to redesign a helium tank.  I believe the "aggressive tanking sequence" is to minimize the amount of time the densified liquid oxygen is sitting in the launch vehicle warming up.  That tells me they probably have alternatives to tweak that sequence so that the thermal stresses on the tanks are not as high. 

While there's much to read about, it's also appropriate to acknowledge the team for a successful return to flight and overcoming the recent failure. 

Saturday, January 14, 2017

Obama's Fairwell Tour

Features a speech in which he mentions himself 75 times, changes the policy for accepting Cuban refugees if they make it to shore (the so-called "wet foot, dry foot" policy), reduces sanctions against the Sudan, and "fundamentally transformed" the US' 68 year old relationship with Israel.  It continues his eight year record of aiding our enemies and hurting our friends.
(Michael P. Ramirez, of course)

Oh, someone's going to pay for it alright.  Everybody in the US is paying for Obama already.

Friday, January 13, 2017

Setting Up To Tear Down the G0704

I've been holding back on you guys for a few days, but since the misadventure of the ballnut removal tool (BRT) and the ball bearing spill, I haven't said that I solved that mess.  I worked on plumbing and posted about that, but getting the balls packed into the bearing and getting the ballnut and screw in place on the Y axis was a major stumbling block.

I succeeded on Wednesday morning.  I had studied a YouTube video a few times and tried repacking the balls on Monday.  It didn't work out.  This guy stresses that there are races in the ballscrew that shouldn't get balls put in them, saying if we did, the ballscrew would jam at some point.  I couldn't see what he was talking about from the video.  About the 10th time I watched trying to see what he was referring to, I seized on a different approach to the job.  Feed the balls into the returns and let them push their way around the races themselves, then I don't need to worry about avoiding a spot.  Wednesday morning, after suitable amounts of coffee, I put on my Optivisors, turned on a back light flashlight, and mixed the spilled 100 ball bearings in grease.  When you watch this video, or many others, you'll see the demo using Vaseline to hold the balls in the race, and it really does work (well, I used Teflon loaded grease - this guy says grease is better but uses Vaseline).  Next thing I knew, within an hour's work, I had all the races full of balls.

Now comes the hard part.  On Monday, I had tried my previous two attempts at a BRT.  Balls got pushed out of place.  After that, I decided to go the route of the cardboard tube BRT, but turned one out of wood.  I had a "pen blank" (pen blank is eBay talk for scrap wood cutoff) I had bought 15 years ago, 3/4" square and about 6" long.  I turned it to slightly over 0.5"; it measures .510 in most places.  I drilled a 5/16" hole down its long axis, then worked up the nerve to enlarge that to 13/32 (.406), in case I needed to try to use it on the ballscrew, not just to retain the balls while I screw the ballscrew into the nut.  Everything held together. 
Attempt 27 at the BRT.  Technically, it's the fourth; it just feels like 27.

Success.  This BRT (and perhaps a bit more care) didn't displace any of the balls, and I was able to screw the ballnut and mount onto the Y-axis in the mill, gradually (and gently) pushing the BRT out the far end.
With this in place, I put the cross slide on and checked for ease of motion.
This is both the X and Y axes in place.  I had to hog out that cutout around the white plastic oil fitting on the X-axis ballnut, in the lower front right, this week too.  Time to check out how far the Y axis moves.  It moves 6-1/2"... wait ... Grizzly specifies the original mill at 6-7/8".  I lost motion?  Back to the DVD videos and finally a quick check with Hoss.  The base of the mill needs to be modified to cut away some metal in the front.  To modify that middle picture a bit:
I need to cut out that square.  It's about 1-1/4" on a side.  This is dead space in the mill, and to be fair Hoss does describe this in the modifications, only he describes it as part of the phase two mods and I'm building phase three.  (Hoss modified his mill sequentially and kept improving it.  It means he did things in phase one or two that anyone doing three needs to know.)  Hoss says I should end up with about 9" of travel.  So I get 6-1/2 now, when I add 1-1/4 cutout, that's only 7-3/4.  Not sure where the rest comes from.  I can only get about another 3/4" at the back, at the most.  The cross slide doesn't hit the Z-axis column; and I think it's from crap in the casting hitting something on the back wall. 
All those bumps on the back wall of the slot are potentially limiting.  If I can pick up 3/4" here, that puts the range over 8" and it's conceivable that there might be some more room in the front.  Hoss gave me this picture to go by.  
My only real trepidation about this is that it means taking the mill completely apart.  As it is now, the Z-axis is attached to this base, and while I know I need to take it apart, I've been intimidated by the weight.  I have the shop crane but haven't figured out how to do this and where to put it when it's off.  The cutting doesn't bother me; it'll probably be done by drilling a series of holes and cutting between them with a big saw rather than with my micro mill.  My guess is that the base weighs around 30 pounds, and the Z-axis column, motor and all have to go well over 100 pounds.  I don't think my little Sherline can handle the 30 pound piece, and a drill press makes a terrible milling machine. 

Thursday, January 12, 2017

Cool Idea - Implementation? Meh

I'd guess that as long as cheap digital calipers have been available around that most people who play around in the shop (wood, metal, or more kinds) have a pair.  A while ago, I saw the calipers on the top in this picture on sale at Rockler's and bought one. 
As you can see, they're labeled General, a long established tool importer and seller.  You can also see the main feature for these: they read out in fractions of an inch, down to 1/64.  1/64 is a bit critical for most woodworking, but they work just fine in the metal shop.  Except for the fact that they're made of a plastic or glass-filled plastic and are therefore not as hard (in the scratch or dent resistant sense) as steel calipers would be.  They also read out in decimal inches or decimal millimeters at the touch of a button. 

Yeah, I have fraction-to-decimal charts around, and yeah, I have memorized lots of fractions in decimal format, but it's really convenient for things that aren't close to a multiple of 1/8, or a few others that are lodged in my brain.  Plus, it's nice to measure something and know that if I measure .143, which isn't in my memory stack, it's "close enough" to 9/64.  They're handy. 

Unfortunately, they also act weird sometimes.  They reset too often and that includes resetting zero or mode. 

Enter the calipers on the bottom.  A few weeks ago, Little Machine Shop listed them as a weekly special, and since they're made of hardened steel, that overcomes one of my objections to the plastic ones. Plus, I hoped the weird resetting was EMI and that more metal on the back of the electronics might help. 

This is where the implementation issue shows up.  I had to go through 3 sets to find one that works.  The first one was fine when I turned it on for a first look, but then I put it aside because lots of other things were going on (it was a week before Christmas).  When I tried to use them, they were dead.  I opened the battery compartment and found corrosion fuzz inside.  I cleaned that out and replaced the battery and found they were random number generators.  They reset constantly, resetting mode and zero constantly.  I wrote LMS to ask for an exchange, and while I was sitting here at the computer not even touching them, they would turn on by themselves, and choose random modes. It doesn't get much flakier than that.

The second pair arrived the Friday before Christmas and wouldn't turn on.  The battery compartment in these was even worse; so full of fuzz it was almost pressing the plastic open.  I wrote LMS and politely said if they would go through their stock and find me a set that worked, I'm interested, if not, send me a refund.  LMS is known for good customer service and they quickly sent me a third set.  These work much better than the other two.  I've had them reset on me a few times, but it seems to come from sliding them open too fast.  They will turn on just by moving the slide, which is different from all my other calipers, and I can't tell you if that's by design or not.

So do I recommend?  When they work, they're pretty convenient, and I tend to keep mine with me, but that 33% success rate bothers me.  I'd be more inclined to recommend them if you could visit someplace selling them and check them out, maybe pick out a pair yourself.  I see a similar caliper at Horrible Freight and I'd bet that one or two companies in China Incorporated make them all.  If you must order by mail, I don't like the odds of going through three to get one good set.  I'll leave that up to you.