On Friday 23 September 2016 02:02:03 hubert wrote:

> 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.

This larger shanked one from the Sheldon tool drawer has a full length 
flat, but its on the open side when put into one of TLM's holders. Any 
others I'd have to machine.  The main bar holder has no provision for 
engaging a flat, so I was trying to use a std tool holder that doesn't 
even have the center groove in the bottom face of the trench. But I've 
got it sharp now, so I think I'll put it back in to finish this part of 
the job as it chatters very little, beefier shank out to the cutting 
edge.  Maybe turn it over and cut the back of the hole, testing my 
tapered gibs I put in TLM. So far, those are working sweet indeed.

So I am not well equipted to use a round butted tool.

> 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.

Bad spell back when the summer heat turned wet too, but doing better now.
Thanks for asking Hubert.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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