# My Dilemma



## Kevin (May 1, 2013)

I started a bowl for my daughter, not realizing my bowl jaws are packed in one of many boxes - many many boxes. IOW I cannot find them easily and don't know how to finish this bowl. How can I turn the bottom off and finish it without bowl jaws? 

[attachment=24150]

[attachment=24151]

The bottom of the bowl is even with the end of the square rule. 
[attachment=24152]


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## WoodLove (May 1, 2013)

do you have a set of flat jaws with pins that you can attach to the chuck you have? the flat jaws can hold the bowl by the rim while you finish the bottom. Thats just my suggestion and since Ive been turning for less than a year I might be wrong or sound foolish. I apologize if my suggestion sucks...... Ill keep watching the thread to see what the pro's say.


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## WoodLove (May 1, 2013)

sorry about that Kevin..... I re-read your post....... yup....... it was a stupid reply. ..... however, another suggestion would be to use a mounting block and glue the bowl to the block and finish the bottom. Use a piece of newspaper as a layer between the bowl and block..... then when the bowl is ready to come off all you have to do is break the newspaper bond. A light sanding and you are done...... I saw is done on a woodturning website a couple of months back. hope this helps..... and sounds less stupid.


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## Kevin (May 1, 2013)

Jamie your reply wasn't stupid. My planning was.  

I'm not too sure about gluing the rim to a block - maybe it's a viable alternative but I would need more info to feel safe doing it.


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## WoodLove (May 1, 2013)

sorry...... I re-read the post and I sounded stupid. Another suggestion is to us a mounting block, glue a piece of paper to it, then glue the rim of the bowl to the paper. finish turning the bowl and then remove the bowl by breaking the bond of the paper. I saw it on a video where the guy was making segmented bowls. I cannot remember what type of glue he used but I know he used his drill press to ensure a good bond of the paper to the two pieces of wood. Hope this helps and sounds less stupid.


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## Mike Jones (May 1, 2013)

Make a "Jamb" chuck.

Turn a piece of plywood (or similar flat stock) with a face plate or tenon so that you have like a disk sander without the abrasive. Next cut a groove in the face of that disk just an RCH larger than your bowl rim so that the bowl fits snugly into the groove. Bring your tailstock up to the bowl bottom and turn away the excess bottom wood until there is just a nubbin. Take that nubbin off with a bench chisel and sand flat. Oila!

For extra confidence the first time around, after the bowl is firmly held between centers, STRAP that puppy down with several wraps of packing tape...the fiber reinforced type tape. And take light cuts, with sharp tools.

Put on some "Marley Music" and sing...."we be Jambin' now, we be jambin' now"


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## Kevin (May 1, 2013)

Mike Jones said:


> Make a "Jamb" chuck.
> 
> Turn a piece of plywood (or similar flat stock) with a face plate or tenon so that you have like a disk sander without the abrasive. Next cut a groove in the face of that disk just an RCH larger than your bowl rim so that the bowl fits snugly into the groove. Bring your tailstock up to the bowl bottom and turn away the excess bottom wood until there is just a nubbin. Take that nubbin off with a bench chisel and sand flat. Oila!
> 
> ...



:lolol:

That's exactly what I will do later this evening. I will show the results. It's for my daughter's birthday so I thank you and she thanks you - she just doesn't know it yet.


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## healeydays (May 1, 2013)

What is that nice piece of wood you used?


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## Kevin (May 1, 2013)

Maple burl. The shape is the result of a bowl set she showed me last year and I turned it from memory. Cody if you see this don't tell Abby and ruin the surprise. 

(Cody is my SIL and he watches this forum routinely)


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## healeydays (May 1, 2013)

WoodLove said:


> sorry about that Kevin..... I re-read your post....... yup....... it was a stupid reply. ..... however, another suggestion would be to use a mounting block and glue the bowl to the block and finish the bottom. Use a piece of newspaper as a layer between the bowl and block..... then when the bowl is ready to come off all you have to do is break the newspaper bond. A light sanding and you are done...... I saw is done on a woodturning website a couple of months back. hope this helps..... and sounds less stupid.



It's funny, but this same method came up in conversation last night. What do you use as glue? One person said use wood glue, the other swore that super glue was the way to go...


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## barry richardson (May 1, 2013)

A couple of ways I do that is simply part it off, angling in tword the center to give it a foot rim. Or part it off straight, then rout a recess in the bottom with a circle template and pattern bit of the appropriate size. Attach the template with double sided tape to the foot. I've used both techniques many times. I've made many many bowls and dont even own cole jaws, but I admit, I'm self taught and have some unconventional ways


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## Charlie_W (May 1, 2013)

Mike Jones said:


> Make a "Jamb" chuck.
> 
> Turn a piece of plywood (or similar flat stock) with a face plate or tenon so that you have like a disk sander without the abrasive. Next cut a groove in the face of that disk just an RCH larger than your bowl rim so that the bowl fits snugly into the groove. Bring your tailstock up to the bowl bottom and turn away the excess bottom wood until there is just a nubbin. Take that nubbin off with a bench chisel and sand flat. Oila!
> 
> ...



Yes, This was what I was thinking too! In the groove that holds the top of the bowl, you could put in some pieces of double stick tape or just a wipe of some 100% silicone caulk (let it dry) to give it a little tack. Then finish the bowl with oil & buff or spray laq.

Charlie


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## DKMD (May 1, 2013)

What Mike said.

Alternatively, you could turn a convex shape that will fit inside the bowl and jamb it against that surface with the tailstock. Use a bit of paper towel or an old mouse pad to keep from marring the surface inside the bowl... That'll leave you a little nubbin at the bottom to deal with as well.


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## Kevin (May 1, 2013)

DKMD said:


> What Mike said.
> 
> Alternatively, you could turn a convex shape that will fit inside the bowl and jamb it against that surface with the tailstock. Use a bit of paper towel or an old mouse pad to keep from marring the surface inside the bowl... That'll leave you a little nubbin at the bottom to deal with as well.



Gary Max talked me through that and I did it, but I forgot to put something between and I did mar the inside of the bowl. Badly. Now I'm going to 

A) Glue a block back on so I can sand inside 
B) Chuck it in the Learnin' Box and start over. 

:dash2:

Sometimes this turning stuff is way overrated.


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## Mike Mills (May 1, 2013)

People have different methods but..
For a friction chuck as David described I would use a concave surface to meet the bowl not a convex. If the end is rounded there is only a small area for contact and it can cause a dimple in the project. The bowl can also wobble easily on it. Using a concave the bowl meets around the circumstance of your chuck; so a 2” diameter chuck would have 6+ inches of contact. 
Think of a tennis ball on a table and try to turn it, turn pretty easy; then cut it in half and put the cut side down, very much pressure and you can’t turn it at all. If you kept your original center dimple on the base from the tailstock to remount it, it is almost self aligning. 

I use a scrap of leather over mine and have never bugger up the inside even when they are finished to completion.

Once you do find your scroll chuck you can quickly turn several friction plates in 2, 3, 4, etc diameter from a piece of 2X6 to have them ready. I try to match the diameter of the friction chuck to the base if possible to have the most support at the outside edge where the heaviest cuts normally are.


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## Kevin (May 1, 2013)

Mike I am pretty sure David meant concave and convex. It's easy to get them mixed up. I have trouble keeping dihedral and anhedral straight. 

I appreciate all these suggestions y'all are going to make a turner out of me yet.


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## DKMD (May 1, 2013)

I've done it both ways... Concave and convex. If I turn a friction drive that is convex, I try very hard to match the curve of the inside of the object. If I'm gonna miss, I try to miss on the side of being less curved than the bowls surface.

Mike's tennis ball example is a good illustration of the impact of surface area contact, but a mating curve provides much greater contact than a ring(which is what you get with a concave surface). Imagine turning the cut tennis ball on a surface compared to a halved solid rubber ball.


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## Kevin (May 1, 2013)

Hmmm. I just cannot see a convex surface working unless the chuck (the wooden shaft of the jamb chuck) also was turned to an OD the same as the smallest ID of the project, because it would wobble wouldn't it? Well obviously not, I mean you are an accomplished turner Doc so what am I missing with that?


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## DKMD (May 1, 2013)

As long as the outside surface of the chuck makes contact, it's no more or less stable than a concave surface... There's just more surface area to drive the piece.


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## Kevin (May 1, 2013)

We're talking the end of the chuck right? If it is convex that means it is "bulged" at the end and the outer "ring" doesn't exist. I know you know what you're talking about but I don't. I know what convex and concave are but I'm missing something here.


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## DKMD (May 1, 2013)

I should say that I don't think it matters either way, and using a concave drive surface is easier to manage... I was just trying to point out that it's not necessarily the only way.

*If* you want to make a convex surface as a drive chuck, it should match the concave surface on the inside of the bowl. If you're going to 'miss' the curve, miss on the side of being under curved(ie. relatively less convex than the bowl is concave)... This will give you rim contact like a convex drive. If you nail the curve match, you'll have the entire surface of the chuck driving the bowl which provides more contact area than any other option.


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## NYWoodturner (May 1, 2013)

Being self taught I have just always done what made sense to me. :dunno:
I turn a disc as similar to the contour of the bottom as i can. I glue on a 320 or 400 grit piece of sandpaper and put a spur drive in the headstock - usually on an extension. I wedge the disc between the spur center and the bottom of the bowl or vase or HF (Sand paper side to bottom of the bowl) and put a small live center in the tail stock. As long as the pressure is adequate there really isn't much movement on the inside, but if there is it only helps complete the next step of sanding. I turn down to the proverbial "Nubby" and remove that with a carving chisel. I have had good results with it and never had any bad marring of the bottom surface. 
The one mistake I have made with it is to put too low a grit sandpaper on the disc and end up making dents and scratches I had to work on later.


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## duncsuss (May 2, 2013)

There are probably as many ways to do it as there are bowl turners -- the way I was taught was to simply open the jaws of my scroll chuck so it just fit into the opening, with some rag or foam padding to keep things from getting scratched up. That's what I used in the case of this bowl, bringing the tailstock up nice and snug to hold it on while I turned the base down to a small nub.

[attachment=24191]

[attachment=24192]

Since then, I've also used large disks of plywood or mdf with a ring cut to receive the rim of the bowl (only works with bowls that have a turned rim, i.e. no good for natural edge bowls). Cut the sides of the groove with a 3* angle, like a morse taper, and it will grip the bowl well.

I've also attached a large lump of wood to a faceplate and turned the end of it to match the inside contour of the bowl (again, use a rag or something to prevent any slippage from burnishing a ring at the contact point inside the bowl).


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## Kevin (May 2, 2013)

Forgetting the rag was the key to my overwhelming failure. I do believe I have learned this lesson though. 


.


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## duncsuss (May 2, 2013)

Kevin said:


> Forgetting the rag was the key to my overwhelming failure. I do believe I have learned this lesson though.



Sorry you had to learn it that way ... if they gave college credits for lessons learned through misadventure, I'd have a PhD by now ...


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## Mike Mills (May 2, 2013)

I agree with duncsuss that the chuck jaws can be used and have done that. I do use a wooden friction chuck/plate if the inside is finished.

When I make them I round over the mating edge about ¼” to soften it. You can make a convex one but it seems you would have to make a new one for each bowl. Concave it will mate with any bowl that is not flat bottomed.

I place a scrap between centers and turn recess or tenon. Mount in the chuck and turn the front with the slight round over at the edge. I always mark the friction plate at the #1 jaw to return it to the same mounting position as much as possible. You may need to re-true a couple of 100ths each time due to warping or mounting error. You should be able to get a lot of use from one plate before you throw it away.

I started using leather after watching a video. With thick foam or other material you may have to apply a lot of pressure from the tailstock just to compress the foam to provide uniform friction. You can crack the base with the tailstock trying to get friction if it is fairly thin. Leather or other thin material (mouse pads?) provides good friction with minimum pressure.

Sometime you may need to glue up some wood to make it an extension if the bowl is deeper than the distance from the headstock to the end of the chuck or if the opening is a smaller diameter than your chuck body.


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## duncsuss (May 2, 2013)

Mike Mills said:


> Leather or other thin material (mouse pads?) provides good friction with minimum pressure.



Good point, I forgot that I've been using a piece of old mousepad for a while, same stuff as wetsuit material (neoprene.)


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