On Tuesday 16 April 2013 06:25:32 Steve Blackmore did opine: > On Mon, 15 Apr 2013 20:17:29 -0400, you wrote: > >But on my small lathe, how would one go about putting tool offsets into > >the tool.tbl that mean something when in changing a tool, the stickout > >its clamped up at is effectively completely random give or take 1 cm > >or so? > > > >To me, it makes 100x as much sense to mount the tool such that it can > >reach its cuts ok, drop the gauge on the ways and simply re-home the > >machine. FWIW, I have an .ini special for boring bars. It searches > >outward to find the contact, but fudges some on the z because most > >boring bars on this gauge will only contact on the end of the bar, > >whereas the cutting tip is typically 1/8 to 1/4" shorter than the end > >of the bar. And again, the amount of stickout is entirely arbitrary. > >In fact I have one home made bar that I can stick out about 8". > >Totally useless at that much stickout unless I'm boring room temp > >butter, but it is doable. :) > > Gene - IF you use quick change holders and tool post, once you have > manually set tools, and don't remove them from the holders, you can > touch off using the tool post body or a probe in a holder. As long as > you clean the clamping surfaces good quality ones are remarkably > repeatable. > > The downside is the price of holders, but I'll bet you'll need less than > you thought you would (or bought ;) > > Steve Blackmore
Maybe Steve, and I did buy some extra cutoff tool holders because I use a specially sharpened cutoff tool as a single tooth thread cutter. For all my tools, I'd need at least 5 more holders at $30/copy. But the QC itself gets loosened and turned because a .125" 2 flute endmill is the best tool for boring small holes. I set it straight, and use a low angle drill bit to rough out the primer pocket for a 209, then mount an 1/8" 2 flute coated carbide endmill in the drill chuck, which is itself mounted to a 3/8" boring bar holder, and turn it so one of its 2 sharp corners is dead level in front, then loosen the whole post and turn it about 5 degrees to me. Makes a great boring bar for a .240" diameter pocket about .250" deep. I should I suppose, make a small collet holder, perhaps using a dremel collet and nut fitted to the end of a 3/8" rod, just to hold the mill better than the 3 jaws of a drill chuck. Need a round tuit though. :) And nobody makes a morse taper style collet anywhere near that small. But after roughing out the hole, you take a shaving cut, tease/scrape it to the needed depth, measure, cut another 2 or 3 thou until you have the final size. Tedious, but not as much as the cutoff tool is when cutting off the finshed exterior part. Much of the rest of making a solid, non-vented nipple is in just 2 other files that assume the QC post is well aligned. All the various diameters are in one file, the thread cutting is in another file I wrote that is a universal thread cutter, doing all the math to wrap up the G76 function so I tell it how many tpi or tpmm, and the length & the rest is automatic. Making them from TSC cold roll stock isn't totally right, S/B stainless I guess, although I haven't figured out what they make the vented OEM versions from, which seem to be both harder, and less effected by the primer & powder residue. Some sort of a medium grey finish on those, but the vents make them worthless, won't put enough fire in the hole to ignite Blackhorn 209 powder without putting 5 to 10 gr of P or 777 down the hole first. These nipples look pretty fuggly at the end of the day but they're a bit like a timex. :) Most accurate powder by far, and its not at all dirty burning as its really a smokeless with smoke, you can load and shoot it 30 times in an afternoon at the range without even a spit patch to clean. But it takes a small tactical nuke to get it started, CCI #209M's seem to be about right. :) But the post does get moved, so the tool table is toast, even with small straight edges to reset it square, the table is still going to be some random value off. That is why I built the gauge to set home with. One of the reasons I need to make the mill holder is because the gauge I made, while it has a 3rd contact surface I can bring into position to set boring bars with, the drill chuck's OD prevents me from using it to auto home a mill used as a boring bar. Another reason to make the holder, and buy another boring bar holder for the QC kit, Thanks Steve. You do make me think of better ways to do it. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! My views <http://www.armchairpatriot.com/What%20Has%20America%20Become.shtml> Abraham Lincoln didn't die in vain. He died in Washington, D.C. A pen in the hand of this president is far more dangerous than a gun in the hands of 200 million law-abiding citizens. ------------------------------------------------------------------------------ Precog is a next-generation analytics platform capable of advanced analytics on semi-structured data. The platform includes APIs for building apps and a phenomenal toolset for data science. Developers can use our toolset for easy data analysis & visualization. Get a free account! http://www2.precog.com/precogplatform/slashdotnewsletter _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
