Help! How Do I Remove Adaptor From Jacobs Chuck

jkmarshall_cues

jkmarshall_cues

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Does anyone know the secret to removing an adaptor from a 14N Jacobs Ball Bearing Super Chuck so I can install a MT #3 Jacobs adaptor that fits the tailstock on my lathe?

I know when I install the new Jacobs MT#3 adaptor, I put it in the freezer for an hour, and put the chuck in the oven at 200 degrees for 30 minutes to mate them.

Thanks for your thoughts.

John
 
Most of the Jacobs chucks have a small hole going on through. So you would put the back side of the chuck down on the end of a phenolic tube or anything for that matter that puts pressure against the back. Then you need a small rod to run down in where the jaws are and tap it with a hammer and the adapter should break loose.
 
The other option is to use a taper breaker. They can be one or two parts. There is a tapered wedge piece that has a slot to go each side of the taper. Or there is a clamp piece that clamps to the shoulder and the taper wedge piece goes through. It just acts like a powerful extractor. Heating or cooling will make little difference. But since you heated and cooled the pieces before assembly, it will be more difficult than normal to disassemble.If it is a genuine Jacobs chuck, then there will be a hole to a pin to be inserted, to allow disassembly.
 
The other option is to use a taper breaker. They can be one or two parts. There is a tapered wedge piece that has a slot to go each side of the taper. Or there is a clamp piece that clamps to the shoulder and the taper wedge piece goes through. It just acts like a powerful extractor. Heating or cooling will make little difference. But since you heated and cooled the pieces before assembly, it will be more difficult than normal to disassemble.If it is a genuine Jacobs chuck, then there will be a hole to a pin to be inserted, to allow disassembly.
 
Get a set of the wedges illustrated. They come in different sizes for each taper. You also might want to freeze the whole assembly for a hour or two(wrap the shank with a wet cloth while freezing, this will help keep it cold for the next step). Then heat up the back of the chuck with propane torch while applying pressure with the wedges.

www.jacobschuck.com

jkmarshall_cues said:
Does anyone know the secret to removing an adaptor from a 14N Jacobs Ball Bearing Super Chuck so I can install a MT #3 Jacobs adaptor that fits the tailstock on my lathe?

I know when I install the new Jacobs MT#3 adaptor, I put it in the freezer for an hour, and put the chuck in the oven at 200 degrees for 30 minutes to mate them.

Thanks for your thoughts.

John
Click to expand...
 
Thanks everyone for your help. I was able to pop out the old adaptor with a pair of tapered shims and now I am waiting for the new Jacobs adaptors to arrive so I can put the chucks to use on my lathes.

Agan, thank you for your help.
John
 
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