Originally posted by bjackman
<br />John,
I'd be interested in any theories as to why you have less runout on your mandrel than you do on the interior slope surface?
Seems to me they should be equal?
Bill,the facts are that several "connections" are playing into this
equation.
1.)The lathe spindle taper to collet chuck shank taper.
2.)The chuck seat taper area for collet to collet exterior taper.
3.)The collet nose taper to collet nut interior taper.
3a.)The collet nut interior thread to chuck body exterior thread.
4.)The collet interior bore to mandrel exterior.
Also,and this <u>is a factor</u>,is simple math:
the .001 runout(rise) at the mt shank will multiply itself over the
distance out to the collet end (run).
If each connection is not perfectly concentric,it will transfer
runout relative to orientation of each mating piece on through
to the next item,be it collet,mandrel,whatever.
Notice I said relative,as in it could multiply,or it could
partially cancel each runout.Progressively turn and try,
check runout to find the best location.Randy's reference to
Russ Fairfield's information is absolutely on track.
Notice in my Lathe gallery that the .004 chuck interior runout
manifests itself as .003 runout on mandrel #1,and .0055 on
mandrel #2.These were turned/fussed with for best readings,btw.
The negligible runout I saw on lathe headstock,and the Beall chuck
having a shorter length,plus made in U.S.A. would lead me,
to go the Beall chuck route,if asked for a recommendation.
And while I have finished blanks on this setup with perfectly
acceptable results,I will use the between centers method,
http://www.penturners.org/forum/topic.asp?TOPIC_ID=16594
(a recent topic by Dario(many thanks!))
to finish more expensive kits.
That's my take on it,thanks for reading![
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