Finishing the base of a bowl

[Keith E Byrd]

I have been turning a laminated ash bowl. It is 7 " tall and 9 1/2 diameter. I have turned the outside, hollowed the inside. I put the cole jaws on my chuck and to my surprize:o they didn't fit. they will only hold an 8" bowl. I tried using it on the inside but couldn't get enough pressure to hold it. So now my problem is how do I finish the base of the bowl:confused:? I have a WoodRiver chuck and according to their website I have the biggest cole jaws for the chuck. I'm sure one of you more experienced and talented folks have solved this problem before and I thank you in advance for helping me solve mine!

[Tim Thiebaut]

Hi Keith, you could make a donut chuck, if you search for "donut chuck" it will bring up many example of it, here is one...

http://www.sawmillcreek.org/showthread.php?40779-Donut-Chuck-Up-Date

I havnt made one myself yet but plan to shortly, this should work for what you need. Tim

[John Keeton]

Keith, chuck up a piece of scrap wood - anything - 2x4, or whatever. Turn a contour on the face of the wood that will fit into the bottom of your bowl. Take a piece of foam drawer liner or similar cushion and place it over the convex end of your "jam chuck". Place the bowl over the cushion, pull up the tailstock into the center mark that I hope is still in the tenon/bottom of the bowl. Extend the quill on your tailstock to give you good access. Then finish the bottom except for a 1/4" "pillar" that the tailstock is in. Remove the bowl and cut off the pillar with a chisel and sand it flush.

[Roger Chandler]

I have been turning a laminated ash bowl. It is 7 " tall and 9 1/2 diameter. I have turned the outside, hollowed the inside. I put the cole jaws on my chuck and to my surprize:o they didn't fit. they will only hold an 8" bowl. I tried using it on the inside but couldn't get enough pressure to hold it. So now my problem is how do I finish the base of the bowl:confused:? I have a WoodRiver chuck and according to their website I have the biggest cole jaws for the chuck. I'm sure one of you more experienced and talented folks have solved this problem before and I thank you in advance for helping me solve mine!

Keith,

Make yourself a Jam Chuck. Use the tailstock to give pressure against it until you have turned everything the way you want it except the little nib that is left where the point of the live center is. With a sharp detail gouge or sometimes even a sharp skew chisel you can turn the nib off as well...........if you don't have a small gouge, then use a sharp chisel to carve the nib off after you remove it from the lathe.

Hope this helps you! A jam chuck is easy to make.........do a search here and you may see some pics............just takes a few minutes to make one that will allow you to do different sizes.

[Steve Schlumpf]

I have a donut chuck that works great for these situations and highly recommend making one of your own - for next time. I agree with John - turn a jam chuck and finish off the bulk of the work on the lathe. Just remember to keep that support pillar at least 1/4" or your bowl could become airborne!

Looking forward to seeing the bowl!

[John Keeton]

Keith, if you end up building the donut chuck (and, you should!), you should also get a "reverse chuck adapter (http://www.woodturnerscatalog.com/store/w9sm/top-sellers/Reverse-Chucking-Alignment-Adapter--reverse-chuck?Args=)." That will let you leave the piece in the chuck, and press it up against the base of the donut chuck for perfect alignment. You can tighten up the donut chuck before you release the chuck from the tenon. Also, the donut chuck does not need to be over tightened. You can bring up the tailstock for support until you get most of the material removed, pulling it back to finish the very center.

[tom martin]

Keith,
There are many ways to finish bowl bottoms. The best way ,without spending money, would be to make a jam chuck. This is how most bowls were finished on the bottom before the advent of modern scroll chucks.
To make one, turn a cylinder long enough so that your bowl will clear the headstock with the cylinder in your chuck. cover the end of the cylinder with either fine sandpaper or foam pad (mouse pad or router pad etc) . Place your bowl on the jam chuck and bring up your tail stock. You may need to adjust a few times if you don't have your center marked. Finish your bottom leaving a small area around your tail stock which will be finished off the lathe.
Tom

[Keith E Byrd]

To all of you - Thanks much! I will use this advice tonight and see if I can finish the bowl - again thanks for the quick and thorough responses!

[Scott Hackler]

I use a "jam chuck" exclusively. Works great for me, but I will say that the most important part of using a jam chuck is planning well ahead that you are going to do this. Meaning that before you turn a roughed out bowl to final shape the tenon "should" be tuned round (by using a jam chuck) so that your center indention (in the tenon) is dead centerin your bowl. That way you finish turn around a center indention that will be perfectly center when you need to turn off the tenon and finish the bowl at the end.

FYI

[Keith E Byrd]

I found this donut chuck project online.
http://syzygypens.com/blog/2009/02/22/donut-chuck/ (http://syzygypens.com/blog/2009/02/22/donut-chuck/)#

[Roger Chandler]

This is a great one posted today..

http://img5.imageshack.us/img5/5136/installedindoughnutchucgn3.jpg

[Jerry Marcantel]

This is a great one posted today..

http://img5.imageshack.us/img5/5136/installedindoughnutchucgn3.jpg

I made a chuck like that, and before the first bowl bottom was turned, I was bleeding like a stuck pig after catching my knuckles on the hex head bolts. I am now using 1/4 - 20 counter sink bolts/screws in place of the hex heads. I also built my donut chuck around my Nova G3 chuck, instead of a face plate.... If you want pics, ask........ Jerry

[Wally Dickerman]

I agree that every bowl turner should have a donut chuck. I've used one for a lot of years. One of the urls posted today had 8 bolts. Real overkill. You don't need more than 3. I use 1/4 inch plywood for the "donuts" because I want to have a little give. I have padding on each donut where the bolt holes are. I have 5 or 6 donuts and several lengths of bolts to accomodate bowls from small to about 11 inches. I used my donut chuck long before cole jaws were invented. In fact before the 4-jaw scroll chuck was invented.

A jamfit chuck that folks used a lot of years ago was piece of 3/4 plywood or a plank fastened to a faceplate. Using a parting tool, cut a groove in the plywood the same size as the bowl rim. Pop the bowl into the groove. With a good fit you don't even need the tailstock. Turners that turned a lot of bowls got good at guessing where the groove should be that they had a good fit almost every time. A small hole should be bored in the plywood because a goot fit created suction making it difficult to remove the bowl. The same chuck was used over and over until there wasn't any room for more grooves. If a 8/4 plank was used the turner just turned off the face of the plank, removing the grooves and started over again.

One easy way to do the base on bowls of 8 inches or more is to leave the chuck on the spindle. Pad it with something like a mouse pad. place the bowl over the chuck, bring up the tailstock and proceed as others have described.

[Thomas Canfield]

Kieth,

The advice on a jam chuck will work and easy choice. You will need to make the jam block fit your chuck or some way to get the clearance for the head stock. A word of caution if the jam chuck does not jam against the bottom is to watch the pressue on tail stock when the tenon diameter gets small to prevent punching through a thin bottom. With 7" depth, your jam chuck will likely seat some distance from the bottom. I have a lot of home made jam chucks made out of a double thickness of MDF and threaded using Beale threader to fit drive spindle. I use 1/2" + 3/4" MDF for 1" drive and 2 thickness of 3/4" for 1 1/4" drive. I also have a 1 1/4" x 3" shaft extension and a 1 1/4" x 1" spindle adapter to work with the tapped MDF jan chucks to work with some deeper bowls.

I do have a donut chuck but find a jam chuck works easier and faster in most cases. It does not care about depth, but then you have to have some size donut plates and bolt lenths.

[Keith E Byrd]

I made a donut chuck last night and will try it out tonight. With any luck I will be able to post a couple of pics of the chuck and the bowl.

[Kyle Iwamoto]

Check e-bay, there is a guy that sells a Longworth chuck. It's pricey, but works pretty good. I've used jam chucks also. Not recently though. The LW chuck he sells fits in the #2 jaws, so you can just chuck the LW in your chuck and you're ready to go. He sells lots of sizes, so he probably has one that you can use. Just another option. No affiliation.