On Monday 07 December 2020 12:16:35 Jon Elson wrote:

> On 12/07/2020 05:11 AM, Gene Heskett wrote:
> > Just one problem. I've not measured it, but I believe the backlash
> > move may be done the instant motion issues the reversal, so it takes
> > place during the spindle slowdown as its still spinning fwd. This
> > results in the resultant thread being cut sloppy as that move is
> > about 2 thousandths of an inch. And its really obviously almost
> > stripped for a fine thread.
> >
> > Now comes the improvement request for two more pins into motion.
> >
> > I need a pin to disable the backlash move, until the spindle has
> > actually stopped.
>
> Well, just another reason backlash compensation really "just
> doesn't work".  Not that the code is bad, the whole concept
> is just WRONG! The ONLY place it mostly works is in X-Y
> drilling operation, where the machine table has tons of
> friction.  In ANY operation where coordinated axis motion
> happens, then the backlash compensation makes things worse.
>
> Tighten up the machine as much as you can, and then maybe
> put a springy tap holder in the spindle to compensate for
> the backlash.
>
> Jon
>
Tighten up, will probably have to start with improving the posts tram. 
Taint vertical by at least a degree.

But who makes a suitable tap holder that isn't specific to just one size 
of tap?  I've likely 40 different sizes of tap shanks taps in that tray 
of 75+ taps in tap hats already. I am not about to buy a tap holder for 
every tap in the tray. A quick search has a price starting at $25/copy, 
up to about $350/copy.

And a/o about 13:30 local, I am alone again. My Dee has passed.

Thanks Jon.

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)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>


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