tag:blogger.com,1999:blog-1592992209402300549.post2047535821553685692..comments2024-03-28T08:06:43.198-04:00Comments on The Silicon Graybeard: One Step Forward, Two Steps BackSiGraybeardhttp://www.blogger.com/profile/00280583031339062059noreply@blogger.comBlogger13125tag:blogger.com,1999:blog-1592992209402300549.post-30253515164991518722016-12-01T21:03:40.912-05:002016-12-01T21:03:40.912-05:00Cast Iron in general is a cool material. I used a...Cast Iron in general is a cool material. I used a sharpened file as a scraper to scrape the ways on an old 1940's mill. Used a surface plate to blue them. Worked great, but should have taken the time to braze a carbide tip on the scraper, as it dulled pretty fast. Amazing how accurate you can get a surface with some bluing and a flat for reference. ravennoreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-9050838264462019292016-12-01T20:57:49.330-05:002016-12-01T20:57:49.330-05:00"When I milled a pocket on it, the chips brok..."When I milled a pocket on it, the chips broke up into little grains, like large sandpaper grains. "<br /><br /> Sounds like cast iron. No idea how much the quality of cast iron can vary regarding machining ease.ravennoreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-37888187538687048412016-12-01T16:04:53.355-05:002016-12-01T16:04:53.355-05:00Thanks for looking that up. I'm questioning w...Thanks for looking that up. I'm questioning whether or not it really is cast iron. I mean, it's clearly cast, but I can't say if it's some steel alloy. I need to research a bit more. <br /><br />When I milled a pocket on it, the chips broke up into little grains, like large sandpaper grains. The sliding surfaces are scraped flat and are quite smooth. I've read that cast iron can tend to keep sand in it, but perhaps the sliding surfaces are machined past that layer and then scraped flat. <br /><br />Really, the only reason I'm saying cast iron is that everyone describes these tools as largely cast iron. <br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-47256239956291224142016-12-01T15:58:15.268-05:002016-12-01T15:58:15.268-05:00I ordered this one from MSC Direct, because "...I ordered this one from MSC Direct, because "I had a coupon" (as my wife likes to say). It was here in 3 days, but free shipping. I have accounts both places. <br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-75216801537481986722016-12-01T15:19:21.297-05:002016-12-01T15:19:21.297-05:00Didja order from McMaster:
https://www.mcmaster.c...Didja order from McMaster:<br /><br />https://www.mcmaster.com/#standard-drill-bits/=15a6ynm<br /><br />They generally deliver within two days...Mark Matisnoreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-63239114229154969152016-11-30T19:29:44.393-05:002016-11-30T19:29:44.393-05:00Just looking at my 1950 copy of "How to run a...Just looking at my 1950 copy of "How to run a lathe", SB recommends dry drilling on cast iron. It is the only metal listed for "dry". <br />Machinery handbook 1970 lists "dry" under cutting fluids for drilling cast iron, with a note that light oil may be used to keep the metal dust down. ravennoreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-24341808903008469652016-11-30T17:24:33.862-05:002016-11-30T17:24:33.862-05:00Thanks. I think they say to use oil, but I should...Thanks. I think they say to use oil, but I should check again. I'm all but certain I have a virgin 1/8" bit, of the typical jobber style. If not, I can get one. FWIW, Hoss said he just drilled the hole. No pilot hole, no succession of hole sizes. <br /><br /><br />I did a little work in cast iron last week, and noticed that the chips were magnetic and stuck to the cutting tool. I assume that eventually can cause a problem, so that's what led me to thinking of peck drilling and lots of chip removal efforts. <br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-19968655788577811902016-11-30T16:49:17.552-05:002016-11-30T16:49:17.552-05:00I would not try to predrill with a smaller bit. A ...I would not try to predrill with a smaller bit. A 1/8" bit with a 135 degree split point has a very small non cutting edge anyway, and the sacrifice of rigidity combined with low chip clearance may be just enough to break off a a 1/16" bit. If you have a short 1/8" bit in good condition, start with that and save the long one till it is necessary-that will retain the edge and help keep the flex down. <br />Also, you may be best with no oil at all on cast iron- see what they have to say on machining forums. I do a fair amount of drilling cast iron and it drills pretty easy. It sort of crumbles out of the hole. Sometimes the oil will make it pasty and harder to clear. See what others say about it. <br /> Is there a sacrificial area you can drill a test hole first without destroying the part?ravennoreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-31273579943219077732016-11-30T16:41:00.293-05:002016-11-30T16:41:00.293-05:00I just finished cleaning up around the big lathe f...I just finished cleaning up around the big lathe from just that.<br /><br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-74217598418690522532016-11-30T16:35:52.251-05:002016-11-30T16:35:52.251-05:00A lifetime ago I worked in a machine shop on a Bro...A lifetime ago I worked in a machine shop on a Brown and sharpe handscrew machine. We got a job in that had a really long hole in bar stock and the machinist who set it up used a D-drill. Since it was new to me I asked him about it and he said that the D-drill will self center as it drills. Another time, a different shop the setup was a regular drill, slow feed followed by a set of reamers for a close tolerance result.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-35150015848781986832016-11-30T13:20:57.665-05:002016-11-30T13:20:57.665-05:00Canned air with a straw will clear chips (all over...Canned air with a straw will clear chips (all over everything)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-74486589504179811962016-11-30T12:17:23.818-05:002016-11-30T12:17:23.818-05:00It's actually a bit worse than 4" deep in...It's actually a bit worse than 4" deep in aluminum. It's 4" deep in cast iron. It's going to take time to do this, but your approach is what I'm thinking. Plenty of Tap Magic, and never drill more than 1/8" without clearing chips. Right off hand, I don't think I have a 1/16" bit that would drill more than 1" in. <br /><br />For what it's worth, Hoss said he did it freehand with a battery powered drill, and told me I was over complicating things.<br /><br />I think you're right on the 5-40 screw: it pulls the taper closed. The 1/4 20 nut has a little cutout milled in it so that the coupler can actually go below the surface of the nut. I think Sherline's idea was that the two fasteners end up holding everything fixed and the taper drives the leadscrew (!), but I can't see that a taper that small would do any good. I'd much rather have a Woodruff key or something like that. <br /><br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-75929279651851331452016-11-30T11:38:54.079-05:002016-11-30T11:38:54.079-05:004" deep with a 1/8" bit? In aluminum? Hm...4" deep with a 1/8" bit? In aluminum? Hm. I am no machinist, but a short drill to start, plenty of good lube, and peck drilling to clear the chips,and attention to speeds. Depending on the alloy. aluminum can gum terribly. What is the hole for? <br /><br /> I am not clear on the 5-40 screw- is that to tension the coupler on the taper? It is the taper that is acting like a collet to hold the coupler to the leadscrew? Is there a keyway or something to keep it aligned? ravennoreply@blogger.com