Sunday, November 20, 2016

How I Spent My Sunday

I've been saying throughout my big project of converting my Grizzly G0704 milling machine to computer control that "every part is a puzzle".  That has taken on whole new meanings as I try to figure out how to add the powered oiling system that Hoss uses on the DVD I bought.  Now it's not a part I'm making that's the puzzle, it's the modification itself.  Hoss chose to put the oiling system on his publicly readable webpage, under the projects tab - conveniently here

I wrote about some of the work I was doing and what was coming soon behind it just a few days ago, and said, "It looks like the biggest task is to cut some channels on the surface of the cross slide that holds the table for the oil to flow between them.".   Since I successfully milled out the area where the ballnut for the X-axis goes on my micro mill, the channels aren't looking so scary right now. 
The cross slide in place on my Sherline mill for a test fit of the ballnut.  Milling the cast iron was tedious and the chips it produces are nasty, but it wasn't really difficult and I never heard the motors bogging down or anything.  (On the other hand, I have a better appreciation for where the saying "a cast iron bitch" comes from!)

This makes the long oil channels seem less scary, and the scary part becomes something that only shows up briefly in the top left video, "Oiling system passages".  Hoss marks off a spot to drill, looking freehand, and then drills a 1/8" diameter hole 4" deep into the cross slide from the one end.  Take a look at this picture I posted a few days ago:
While the hole doesn't go in the end closest to the camera in this picture, look at the marked lines on the right dovetail.  Looks like crosshairs or a target indicator.  Hoss drills the hole 4" into that piece, parallel to the table. 

One of the things I learned very early in my hobby machining is that drill bits can wander and not produce straight holes.  This is why standard drill bit sets have shorter bits for smaller diameters and longer bits for larger diameters.  The ratio of length to diameter is set to reduce the chance of wandering.  Most 1/8" bits have a fluted length of around an inch to 1 1/2.  This one needs over 4" fluted length.  I needed to order a 1/4" ball end cutter for the channels (coulda sworn I had one), so I ordered an exotic drill bit to drill the long hole, too.

As a result, I spent a lot of today trying to figure how to drill this with the best chance of success; going through the shop trying to find something I could rig up to hold the cross slide perfectly vertical for the drill press - or use the G0704 itself.  I could try to do it like Hoss does and just chuck up a long drill bit in my cordless drill and start drilling, or I could try to set the cross slide up with some sort of fixture that improves my chances.  And I swapped messages with Hoss.  He said, "you're over engineering this.  Just drill the hole".  Yeah, I can tend to do that. 


  1. I do the same thing.

    I built a box that has 3 XLR audio connectors and three "cable glands" on it for the Iowa a couple of weeks ago. One of the legacy radio guys gave me a conduit box, some mismatched connectors, a scrap of aluminum to make a cover plate with, and some conduit bushings to run the cables into the box with.

    It would have done the job, but looked like a POS.

    SO....I went out and got a nice LMB cast aluminum box, three matching female XLR connectors, and three water tight cable glands. I made some angle brackets from 1-1/2" aluminum angle so it would mount to the wall, and spent several hours laying it out and drilling all the holes.

    It looks great.

    The other radio group I built this for is of the "nobody else will see it so we don't care what it looks like" attitude, but I just can't do things like that.

  2. G mornin SiG. Check out these (if you haven't already). You could make a drill bushing to captivate the drill and keep it in line if you wanted.

    Chicago-Latrobe - 1/8 Inch Diameter, 6 Inch Overall Length, High Speed Steel, Oxide Finish, Aircraft Extension Drill Bit

  3. Thanks, Irish.

    MSC is where I ordered the fancy bit. The one you linked to has a flute length of 1 5/8", the one I ordered has a flute length of 4 1/8. It's #01468081. Although the MSC Direct/Enco site saved me $5 on it, it still buys several of the one you sent.

    One of the things I was thinking of was something like those tap guides you see that help you keep the tap perpendicular to the work while tapping. I'd have to take it off before the end of the hole, but I'm going to have to pull the drill to clear the magnetic swarf constantly anyway. By the time the bit is 3" in, the work keeps it vertical. (tapping guide

  4. Is there going to be a four inch long hole drilled for each side of the table?
    Are you going to drill from the oil groove to intersect the four inch hole?
    How how you going to connect the oil line to the drilled hole?
    Could you drill down from the oil groove, and then meet that hole by drilling in from the side of the table? (you could then connect the side hole to the oil supply with a braided stainless steel car brake hose)
    Could you drill a somewhat larger diameter hole, 3/16" or 1/4" to make an oil supply gallery, and then drill your 1/8" hole down into the gallery? (you could tap the larger hole for a NPT connection)

    And I am on the side of you and drjim, unless some immediate action is needed, I am going to think this through very carefully, because even if you reverse the drill bit, it does not fill in the oops hole when you withdraw the bit from the workpiece.

    1. There's only one long hole and it goes in the back, right to left. Yes, a 1/8" hole from the oil grove goes down ~.250 or so and intersects the 4" long, 1/8" dia. hole. Hoss used snap-on connectors for the oil connectors in most places, instead of the simpler barbed connectors that tubes press on to. Those are nice, but kind of pricey.

      Reference my photo, top, which shows the cross slide the way you see it on the mill. Front toward you and left/right are correct.

      The front has a plastic scale marker that extends above the cross slide's top. Hoss pulled that off and mounted an oil fitting there. Drilled into the cross slide, front to back, then drilled down into that hole so the oil can be forced up into the groove. These are short holes, about a half inch long horizontal and a quarter inch vertical. No big deal.

      This approach can't be done on the back, because the oil fitting would bump into the Z column and reduce the the travel of the Y axis, which is kind of short already. The long hole puts the fitting on the right side where it won't bump into anything. Oil is pumped into that 4" long hole and it oozes out of the 1/8" top hole in the middle of the groove.

      The whole thing seems a bit iffy, but it works for him and (I think) others who have duplicated it.

      Everything is connected by clear plastic tubing, and driven by a car fuel pump, which delivers about 5 or 6 PSI. Nothing else around the mill runs on 12V, so I need some sort of power supply and control box to pump oil on demand. Maybe from a command in the CNC file.

      Now, if I had thought a bit more, maybe I wouldn't have bought that fancy drill bit, and put in two shorter holes, one on each end of the slide with a conventional jobber drill bit, and put a fitting on both ends of the slide. I'd drill two holes from the top down into shorter cross holes, closer to each end, and just force the oil into the groove that way. I think I could run the plastic tube between the table and the Z column. If not, I think it could run around the back of the mill to the other connector. Once the tubes are full, the extra length won't matter.

    2. Forgot to add that an "oops hole" doesn't bother me as much as breaking the bit off in the cross slide. This like the broken tap, only many times worse. I don't think the bit could wander enough to come out in the wrong place.

      I'm more concerned about drilling my cross hole down into the 4" long oil channel and finding it isn't there. The drill wandered and now there's no channel where it's supposed to be. And now I have no idea where to drill to find it.

  5. I found a blogger who converted your exact mill to CNC, and I sent you the links and a screen capture of his oiling manifold.

    I was, and still am, machining a Stuart Models 3/4" bore, 3/4" horizontal mill engine. One of the angled hole in the steam chest did NOT meet the other hole. (because depending on where you are measuring from, a 60 degree angle can also be a 30 degree angle)

    1. The system he's using is basically Hoss' system, but he redesigned it. Rather pretty use of brass parts and tubing.

      There are no 4" long holes. The hole in the groove for the oil to work up to the top is close to the back left corner.