axminster internal and external jaws

[andy43]

Afternoon all
I have both sets of these jaws and was wondering what they can specifically used for. Can the external jaws be used for holding rounds that are a smaller diameter than my c type dovetail jaws retract too?
many thanks
Andy

 

[CHJ]

Impossible to answer without knowing the part numbers/specific axminster name for the jaws (edit: and chucks) you are referring to.

But the axminster catalogue gives you the design target dimensions that give you maximum grip potential when set to true circle.

From this true circle you have the variations of diameter available from the travel of the carriers in the chuck body, and this is different for 80, 100, 114, and 125mm chucks.
However the gripping efficiency of any gripping jaws and the amount of bruising of the wood as a result of the move away from the ideal circle is something that needs to be considered when used this way.

 

[andy43]

Hi Chas
Its the internal and external set from Axminster item code 717476, there is no additional info for these on the website. The chuck I have is the clubman SK100.
Cheers
Andy

 

[CHJ]

Bare in mind these are not wood gripping jaws and should not be used for wood items without tailstock support of the piece.

The smallest drill that they will grip is in the order of 3mm on the internal faces. (may vary as current production jaws differ fractionally from earlier sets)
The smallest spigot in the stepped internals is in the order of 34mm but this is smaller than the true circle for the jaws

The largest bore in the external jaws is in the order of 75mm.

Easily measured yourself if you fit the jaws to your chuck, that's what I have done to answer this post..

 

[andy43]

Thanks for the info Chas,
It has answered my questions, just one more question, would i be better with the O'Donnell set or the cyclinder set of jaws? I have been given some small diameter timbers 2.5" and i would like to turn some small goblets (hollowing out in to end grain) which set would be better for stability? Sorry about all the questions but if I dont ask I dont learn
Thanks
Andy

 

[Paul Hannaby]

The best jaws for your purpose would be the 80mm gripper jaws (410171) which have a 40mm internal diameter. They are deeper than the int/ext jaws and have serrated surfaces for better grip. This type of jaw works particularly well for spindles you are holding at one end - hollow forms, goblets etc.

The next size up (410170) could also be used, which have a 55mm internal diameter. It depends on the range of sizes you envisage turning.