Adjusting A Taper Bore

When I made all 3 of mine I used snap gauges and Mics to check size.
40 mm start of taper and 30.5 mm back of taper
depth 34.9 mm

All 3 fit tight and contact all around collet.
 
The brain can conceive of an accuracy of 0.0006 but unfortunately the hands lag a touch behind.
It works, the collet is repeatable, no measurable runout on the holder but using a stainless rod tight in the collet it has between 0.0015 - 0.002 runout.
But it is better than my 3 jaw just not as good as I was hoping.
collet-finished.jpg
 
savarin said:
The brain can conceive of an accuracy of 0.0006 but unfortunately the hands lag a touch behind.
It works, the collet is repeatable, no measurable runout on the holder but using a stainless rod tight in the collet it has between 0.0015 - 0.002 runout.
But it is better than my 3 jaw just not as good as I was hoping.
View attachment 132452
Click to expand...
Is that a precision ground (not centerless) rod?
 
savarin said:
it is better than my 3 jaw just not as good as I was hoping.
Click to expand...

That's exactly my reaction to mine. I have yet to see if how tight I make it on the spindle affect the runout, but Savarin's experience was exactly mine. Various!
 
Me too.
The ER chuck taper run out was under .0002'' but once the collet was in and tightened runout of the test dowel was .0015''. I believe the collet and nut contribute to run out. Someone (I think it was Wreck-wreck) mentioned that the quality of the nut has a lot to do with it.

Great job Savarin, that's as good as it gets.
 
Thanks guys, youve made me feel better.
I will test again with an end mill and different sized collets.
This was a very interesting lesson considering all the things that went wrong.
 
Tested 4mm, 8mm, 10mm and 14 mm end mill shanks.
Total runout on all of them is 0.00125"
 
Sorry Tozguy your totally out of luck.:laughing:
On account of all the comments above I have decided its a keeper and have tarted it up a tad.
Untitled-1.jpg
Next - a go at blackening when I get the pot sorted.
 
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