Centering a bowl on a donut chuck

[Norm Zax]

Built my first donut chuck and used it to remove a tenon on a small dish. Came out nicely, though clearly off center :(. If you own such a chuck, whats your method of centering the piece to be finished?
Thanks...

[Steve Schlumpf]

Norm - I use the tailstock to lightly hold the bowl in place on the donut chuck - then give it a light spin by hand to see how well centered it is before tightening the donut chuck. You also have to make sure that you tighten each bolt on the chuck equally because as you tighten the bolt - it pulls the bowl in that direction.

Once the bowl is tightened enough that it stays somewhat centered - I then remove the tailstock and use the original centering hole in the tenon as a reference point to finish tightening the donut chuck. Make sure to spin it every once in a while while tightening to make sure you haven't pulled it out of center.

[Grant Wilkinson]

I have an adaptor that allows me to mount my scroll chuck on my tailstock. That way, I can loosely put the bowl in the donut, grab the tenon with my chuck so that it is held on centre, and tighten the donut chuck. I do the same thing with my vacuum chuck. Works a treat.

[Michael E. Thompson]

More or less what Steve said. I always make sure to leave the live center mark in the bottom of the tenon. So after you finish the inside and reverse the bowl for the donut chuck, use your live center to position the bowl in that center mark. Also as Steve said, tighten up the chuck evenly, rotate it a couple time to make sure nothing moved. I will usually leave the live center in place until I am ready to clean up the center of the foot. Just a little added security. Hopefully this made sense.

Mike

[Bob Hamilton]

Hi:
The easiest way is to make a centering dimple in the middle of the tenon before you reverse the piece to hollow the inside. Then use the tail center in the dimple to center it on the donut chuck.

If you haven't got a dimple when you go to mount it on the donut chuck then what I do is steady a pencil on the tool rest and touch it to the side of the tenon with the bowl spinning slowly. Stop the bowl and adjust it so the center of the pencil mark on the tenon will be further away from the tool rest. Keep doing that until the pencil mark extends all the way around the tenon.

Good Luck!
Bob

[scott schmidt grasshopper]

I bring my tool rest up from the tailstock area ( parralel to the bed) and use it as a referance point( rest not tightened) then touch it to the foot of the bowl, handspin the bowl in reverse and the tool rest will show you the high point. loosen the donut chuck a bit then tap it over to correct by hand. this gets it within a 1/16 for me which is good enough unless I am making a foot or such then I just keep at it until near perfect

[Don Geiger]

Google: Geiger's Re-Centering Solution

I use it every time I turn.

[Malcolm Tibbetts]

Norm, the most accurate method, as long as your bowl is not a natural edge, is to turn a shallow groove in the base plate - sort of a very shallow jam chuck. This not only centers the bowl, but also prvents it from slipping during the last bit of turning. Works for me.

[Bernie Weishapl]

Norm when I get ready to put a bowl or platter in a donut chuck, I leave the chuck on the tenon. I use one of these in the tailstock then mount the chuck and bowl on it. I bring the tailstock up against the donut chuck and it is centered. Never have had a problem.

[Joe Little]

I know it was a while ago but I wanted to say thanks, that was a great suggestion Bernie. I too was having trouble centering my bowl on the donut chuck. I bought a tailstock chuck adapter after reading your post and boy is that slick, perfectly balanced everytime. As usual, great tips come from this forum.
Joe

[Bernie Weishapl]

Your welcome Joe. Works really slick and haven't had a problem with centering since I got it.