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Help with remounting a bowl

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Burt25

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I have been given a bowl by a friend who's uncle had started turning it and then sadly passed away so Ive been asked if I can finish it.
Problem is Im not sure how best to remount it on the lathe? The bowl is mahogany (heavy) and is approx 12" diameter.

There has been a shallow recess cut in the base and the raised 'ring' is unfinished so I suspect he was planning to use a glue chuck to remount.

Should I remount on a face plate / true up the outside and create a dovetail recess to mounting on my chuck to hollow out the inside or would a glue chuck be strong enough?

20170508_105205_resized.jpg
 
Phil Dart

Phil Dart

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The recess you are showing in the photograph look insufficient to be of any use Ian, and even if it was, it is SO shallow that you would need to be certain that your own jaws will hold it as well as his might have done, for which the recess was designed. The thing is, you will have the devils own job to accurately centre it with a glue chuck, even though, if you are sensible and cautious, with the aid of the tailstock I'm sure it would hold.

However, you imply that the inside has yet yo be hollowed, in which case, unless it's already half hollowed, there must be some method of holding, still in existence on the front face. Is it feasible to remount on the front face and re-cut the recess to suit your purpose?
 
B

Burt25

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Phil Dart said:
The recess you are showing in the photograph look insufficient to be of any use Ian, and even if it was, it is SO shallow that you would need to be certain that your own jaws will hold it as well as his might have done, for which the recess was designed. The thing is, you will have the devils own job to accurately centre it with a glue chuck, even though, if you are sensible and cautious, with the aid of the tailstock I'm sure it would hold.

However, you imply that the inside has yet yo be hollowed, in which case, unless it's already half hollowed, there must be some method of holding, still in existence on the front face. Is it feasible to remount on the front face and re-cut the recess to suit your purpose?
Click to expand...

Thanks Phil - The recess is pretty much useless for any chuck jaws as its only about 3mm deep and no dovetailing. - I think it was intended to be glue mounted (hence the ring on the base has no finish on it).

Im thinking of remounting on a face plate and lightly skimming with flat scraper to ensure the bowl is concentric, then true up the base 'ring' making it slightly concave. I was then going to accurately match the diameter of the ring with a waste piece of wood which I would glue to the ring as a glue chuck - hopefully I can get it pretty close to avoid run-off. Whats the best way to get if off the glue chuck when done to finish up the base?- Im assuming hot melt glue (which I understand can be reheated to break the bond?)- or would I be better using some Titebond and a layer of brown paper and separating with a chisel?
 
Phil Dart

Phil Dart

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Is there no holding method remaining on the face? Can you not just make a sensible recess to fit your chuck? A glue chuck for reverse chucking is a nightmare - you are extremely unlikely to be able to centre it
 
B

Burt25

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Phil Dart said:
Is there no holding method remaining on the face? Can you not just make a sensible recess to fit your chuck? A glue chuck for reverse chucking is a nightmare - you are extremely unlikely to be able to centre it
Click to expand...

I can certainly screw a face plate on to the face of the blank - I was just trying to avoid cutting a new recess as its already a very fairly shallow bowl, but if you think the glue chuck will be a real pain I will take your advice.
 
Phil Dart

Phil Dart

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The only way you will successfully centre a glue chuck for reverse chucking is if you fit it and form it whilst the piece is mounted from the face.

So now you've said you can get a face plate centred on the face, and you've also said it's a shallow piece so you'd prefer not to cut a deeper recess, the approach I would take is to mount it from the face on your faceplate, true up the outside, (and there are one or two knocks and dings you'll probably want to get rid of), then whilst still mounted on the face plate, glue on your glue chuck. True that up and form a tenon to fit your jaws in compression, then reverse chuck.

It can't help but be centered that way, and assuming you have the chucking capacity to remove the glue chuck when you're finished with it, then mission accomplished.
 
Terry Q

Terry Q

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I assume the inside hasn't been started. Make sure the bottom is flat and glue a block to make a new tenon. You will have to reshape the outside but if you are careful gluing the block it should be a slight change.
 
Bill Mooney

Bill Mooney

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There's not much of a gluing surface on that ring. I would mount a piece of waste timber in your chuck & turn a tight recess to the outside diameter of the ring on the bottom & jam it into the recess. Bring your tool rest up to but not touching the outside of the rim. Turn the bowl slowly by hand to see if it runs true by looking at the gap between tool rest & bowl. Tap it till it runs true. Then bring your tailstock up to press the bowl right in your jam chuck then put 4 or 5 good spots of hot glue where the bowl meets the jam chuck. Put your drill chuck with appropriate drill in the tailstock & drill a hole to take a big screw chuck. Do this at a slow speed. Reverse chuck your bowl on the screwchuck & bring up your tailstock for safety. This will also mark your centre if you need to rechuck. You can now create a better recess & true up your outside to a finish.
Stay out of the line of fire & take slow light cuts to avoid a snatch. Once the outside is done rechuck using the recess & turn as normal. Always keep your tailstock in place as long as possible for safety.
Best of luck.
 
Penpal

Penpal

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All of the conjecture would be solved with more pics to indicate the rest of the piece otherwise it has turned into guesses so far. When you state it is too shallow for example it infers that the inside has been commenced otherwise deepening the base connection truely and the situation is over.

Peter.
 
Dalboy

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I have turned a bowl with a 1/8" chucking point as long as you keep the tool sharp for easy cuts and take smaller cuts than you would when using a correct size tenon/mortice, Bringing the tail stock up and using a revovling centre to support for as long as possible.
 
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