Hi Mac

Yes I know what you are talking about, the way I deal with it is like
this, I make sure that the face around the tenon or inside the recess,
is flat and clean and square, (I use a sharp scraper for that, NO
sanding) then place the work piece on the chuck and pushing in the
center ( in line with the spindle ) while tightening the chuck, I do NOT
squeeze the living daylight out of the wood, ( wood will distort
differed depending the grain of the wood )(face grain end grain knot
etc. ) now I will give the wood a quick spin, with my tool rest close so
I am able to see how much if any, the work piece is running out, if its
out more than I like, I will find the place where the side of the piece
is farthest away from my tool rest, that is the side where it is not
seated properly against the chuck jaws, I will use whatever is handy but
use mostly a mallet to get it to seat better if loosening and
retightening at a different place does not help, now I will check if the
piece is seated better (I usually have to mark the wood so I know if
things do improve or if I need to use more persuasion and also look if
the wood has changed shape because of drying, 2 equal high and low spots
is than the best I can do, and yes I do keep in mind that there is
always some flexing going on in the whole setup, like give in the wood,
chuck and shaft and bearings, machining tolerances can ad up, but
normally speaking I can get the wood to run very close to perfect, like
maybe 10 to 20 thou. out, certainly less than 1/16"
One more thing I make sure that the tenon is not so long that it bottoms
out, or the recess is to deep.
Hope this is some help, if you like some clarification ( It's clear to
me Big G) just ask, I will try to ad to or improve my answer.

Have fun and take your time and care
Leo Van Der Loo

mac davis wrote:

ok Leo.. here's an area I'm having trouble with...

I'm trying to get away from faceplate turning, to avoid the wasted
wood.. (hoping to get into some more exotic wood than firewood)

I've been experimenting with roughing out the bowls between centers
and leaving them with either a base or tenon for the chuck, so I can
do the rest of the turning with the Talon..

My problem is that whether I use a tenon or a base, the bowl won't
true on the chuck.... a neighbor that works in a machine shop thinks
that the base or tenon might not be true with the face of the bowl and
that if it isn't, the bowl won't true out no matter how much you carve
away at it...

Logic tells me that if something is true when between centers, it
should be true when chucked, but I must be missing something here...
H E L P ! !


mac

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