DIY foam jam chucks for reversed bowls

[Shay Vings]

Lets say we are at the point where both sides of the bowl are finished but you need to remove the spigot:

Ideally reverse it on to cole jaws but I have none. So has anyone tried making a custom jam chuck using aerosol expanding foam?

Toolstation have a low expanding type as well as the usual expanding foam. My idea is to line the turned bowl interior with cling or kitchen foil, fill it with foam and saw it flush. Then stick to a backing plate in the 3 jaw chuck after lining up the tail centre into an existing mark to centralise.

Not sure whether this would be any better than just pressing the reversed bowl agains a flat plate with a router mat?

 

[Paul Hannaby]

I have used foam jam chucks in the past but found they allowed too much movement so now I use a slightly domed piece of wood with a layer of router mat and kitchen roll between it and the inside surface of the bowl. The piece of wood runs inside the bowl, not on the edge so I have a few different sizes and shapes to suit the bowl.
I'm not sure the aerosol foam would be any better because once it's significantly deformed, it doesn't bounce back so before long, it would be out of shape. Or are you suggesting using fresh foam for each bowl? That could work out expensive!

 

[CHJ]

Fix some 10mm or thicker MDF to a faceplate and turn it as big a diameter as possible to clear your lathe bed.

When cutting the spigot in the first instance mark the centre of the spigot with the skew laid on its side so that you have a centre location point for reference.

When you need to 'mount' your bowl to clean up the base use a piece of non-slip matting against the MDF faceplate and trap the bowl against it with the tailstock fitted with a revolving centre.

You can now with light cuts remove all but a final couple of MM of the spigot, if the 'drive' slips then use some masking tape to bind the bowl to the faceplate rim.

There are a couple of alternate methods shown in the information sticky linked at the top of the section, variations on either of the final finishing methods should be achievable.

 

[cornishdave]

I also have had problems removing or tidying up the spigot on bowls and not yet having a set of cole jaws,
today I have made a MDF disc as described in CHJ,s post and it works a treat as long as you keep the cuts light. Thanks for posting this idea CHJ.
Regards Dave.