On 9/23/16 12:02 AM, Gene Heskett wrote: > Greetings all; > > I just had a heck of a day. That round bar of alu fell out of my mailbox > the middle of the afternoon, so I thought I would get started on cutting > out that custom timing sprocket hub. Sawed off the length I needed > (first cut on my repaired bandsaw, cut nice) and chucked it up on TLM. > > Spying a well worn boreing bar about the right size in the stuff I got > with the Sheldon, I clamped it up good and tight in a tool holder & > adjusted everything to center it, started TLM at about 200 revs and > marched into the end face, intending to bore straight in to the depth it > would take to clear the nut on the near end of the X drive shaft. > Pecking by hand, I was getting a nice coil of alu cuttings for about the > first half inch, then it twisted itself out of the holder. Repeat 3 > more times. Gotta be a better way, spied the little QC's boring bar > holder & moved the tool to it, tightening its clamp screws to about 1/8 > turn from stripped. Hung it up and spun it out of the holder, polishing > the but end of the bar rather nicely. Repeat a couple times, with stops > in between to sharpen it with one of those 1.75" Dremel diamond wheels. > Same story, spun it in the holder 2 more times, gave up and put a 3/8 > drill in the holder. That worked for a starter hole and the bar then > ran in and tried to uniform the hole, looking decent but taking a much > wider chip after it got into the drilled portion. So I think I can > write some code in the morning to finish those two bore jobs. > > So what I am looking for is a bb holder that will work with the smallest > QC holder. And will hold it solidly in the face of a 1 horse motor's > solid torque. I am no expert but I know on my 14" lathe that many of my boring bars have flats on one side that keeps them from twisting in the tool holder. With these I am more likely to spin work in the chuck than the tool holder. How is the wife doing? I lost my first one to Cancer about 4 years ago. That interrupted my self taught machining for a while. Good Luck Hubert > > Ideas welcome. > > Cheers, Gene Heskett
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