Chuck Jaws

[woodpig]

Do any of you know at what position the carriers need to be in for the jaws to form a perfect circle? I have the Axminster Clubman.

 

[Stiggy]

EDIT - deleted as misunderstood again - sorry!

 

[Grahamshed]

Or do you mean how far in do they need to be for a full circle hold ? in which case I think it is about 1/8 of an inch from fully closed.

 

[CHJ]

Do any of you know at what position the carriers need to be in for the jaws to form a perfect circle? I have the Axminster Clubman.

For 100mm Axminster chuck See here

If you look at any of the jaws specifications you will find the optimum diameters, I think a gap of 4 mm's is about right to achieve this.

For instance 80mm jaws that I regularly use on 100mm chuck.

A perfect match for the SK80 chuck these popular C jaws feature three separate gripping methods. An external dovetail which opens into a 50mm recess, a 40mm internal diameter stepped shoulder for a firm grip on the outside of a spigot. A screw chuck can be purchased separately for use with these jaws. Recommended range: 35-55mm internal, 50-70mm external. Although designed to fit the 80mm chucks these jaws will also fit the 100mm versions.

 

[selectortone]

For 100mm Axminster chuck See here

I have two Axminster 100mm chucks - that document is really useful, thanks for posting the link.

 

[woodpig]

Or do you mean how far in do they need to be for a full circle hold ? in which case I think it is about 1/8 of an inch from fully closed.

Yes, that's it. If fully closed the jaws clearly don't form a circle.

 

[woodpig]

For 100mm Axminster chuck See here

Thanks. I didn't realise those dimensions represented circularity. I'll have to set my C jaws at 27mm then remove them and carefully check the diameter between the carriers. 27mm is not a very helpful size, I wish they'd made it 25mm then I could have used some 25mm bar or turned down some 1"!

 

[CHJ]

Thanks. I didn't realise those dimensions represented circularity. I'll have to set my C jaws at 27mm then remove them and carefully check the diameter between the carriers. 27mm is not a very helpful size, I wish they'd made it 25mm then I could have used some 25mm bar or turned down some 1"!

What on earth are you trying to achieve? If you have auxiliary jaws fitted then you just make any sockets or spigots to conform somewhere near the true circle dimensions of the auxiliary jaws. For light loads and sockets that are to be removed, therefore no consequence if they get bruised, then 4 to 5mm diameter oversize error is not a problem.

If you are turning your own custom jaws attached to the carriers or a wood plate auxiliary jaw set then the Carrier position PCD is immaterial as long as it is within the safety travel range of the scroll. Just clamp the nose of the carrier onto a suitable piece of wood for stability whilst cutting register.

Why would you want to set the carriers precisely to a given bore dimension.

 

[woodpig]

I'm thinking of making some of my own jaws and want to get the recess for the carriers as close as possible to the correct size. I didn't ideally want to judge it solely by eye.

What on earth are you trying to achieve?

Any particular reason for the rudeness Chas? :roll:

 

[CHJ]

I'm thinking of making some of my own jaws and want to get the recess for the carriers as close as possible to the correct size. I didn't ideally want to judge it solely by eye.

What on earth are you trying to achieve?

Any particular reason for the rudeness Chas? :roll:

Wasn't intended to be rude, I'm genuinely at a loss to understand why you would want to achieve precise positioning of jaw carriers in the chuck body for wood related work.

The whole point of the normal wood turning holding methods is that definitive accuracy is achieved by the operator cutting to size.

Projects requiring repetitive precise diameter stock holding resort to using Collets.

If you are making Auxiliary jaws to locate on the carrier location/centrifugal safety keys then it would be simply a case of measuring the diameter with a micrometre or vernier when they are set to a true circle, no need to fit auxiliary jaws, you can't rely on the carrier nose bore to be true across various chucks and carriers, although the scrolls are a match, the nose protrusion (Vee) on the carriers has varied over different production batches, indeed it often varies by a few thou. on individual carriers. This can be seen when fitting auxiliary jaws to older and new carriers.

 

[woodpig]

Oh dear, you seem to have got yourself into a bit of a tizzy Chas.

If you recall this thread started with a simple question:

Do any of you know at what position the carriers need to be in for the jaws to form a perfect circle? I have the Axminster Clubman.

I didn't give a reason for asking it as it didn't seem relevant but as you've wound yourself up making lots of wrong assumptions I feel I should put your mind at rest.

I happened to mention to someone that Axminster tools only make button jaws (I bet the penny's dropped at this point but I'll continue) in either 150mm, 250mm or 400mm sizes which isn't so useful to my 350mm capacity lathe. The cost is also quite high at £164.95 for the larger ones even if they did fit.

Knowing that I make a lot of my own tooling It was suggested I make my own and it was even mentioned that some suitable allow plate may be made available to me free of charge.
I'm not actually sure of the practicality of doing this but a simple test on some small scrap may prove the point.

Hence my original question.
If I intend to do this I want to make the groove to locate the jaws as accurately as possible. I hope this makes things clear.

Apology, such as it is accepted by the way.

 

[J-G]

I can't let this pass without comment - and I don't comment that often !!

I find your response, woodpig, much more offensive than Chas' ("...apology, such as it is..." :roll: ) and your original question slightly incomprehensible.

The position of the carriers is totally irrelevant to the jaws forming a 'perfect' circle. You could have asked something along the lines of "at what position do I set the datum grooves to make sure that the carriers will be within the body of the chuck" but you could easily measure that without jaws on the carriers.

I don't think Chas is in a 'tizzy' at all. His answers have all been very rational. If anything I suggest that you are in the 'tizzy'. Did you really mean "...that some suitable allow plate may be made available..." or should that have been 'Alloy' - - - neither option make sense to me.

Oh dear, you seem to have got yourself into a bit of a tizzy Chas.

If you recall this thread started with a simple question:

Do any of you know at what position the carriers need to be in for the jaws to form a perfect circle? I have the Axminster Clubman.

I didn't give a reason for asking it as it didn't seem relevant but as you've wound yourself up making lots of wrong assumptions I feel I should put your mind at rest.

I happened to mention to someone that Axminster tools only make button jaws (I bet the penny's dropped at this point but I'll continue) in either 150mm, 250mm or 400mm sizes which isn't so useful to my 350mm capacity lathe. The cost is also quite high at £164.95 for the larger ones even if they did fit.

Knowing that I make a lot of my own tooling It was suggested I make my own and it was even mentioned that some suitable allow plate may be made available to me free of charge.
I'm not actually sure of the practicality of doing this but a simple test on some small scrap may prove the point.

Hence my original question.
If I intend to do this I want to make the groove to locate the jaws as accurately as possible. I hope this makes things clear.

Apology, such as it is accepted by the way.

 

[CHJ]

.......Knowing that I make a lot of my own tooling It was suggested I make my own and it was even mentioned that some suitable allow plate may be made available to me free of charge.
I'm not actually sure of the practicality of doing this but a simple test on some small scrap may prove the point.

Hence my original question.
If I intend to do this I want to make the groove to locate the jaws as accurately as possible. I hope this makes things clear.

.

In that case I am amazed that you can not quickly measure the true PCD of the location/safety keys and have to ask on the forum for this information, it is a matter of 20-30 seconds at most to find and measure.

I found this a more flexible solution than making larger diameter Cole Jaws back in 2007.
(For those who don't have a 114-125mm chuck for increased range diameter options then offsetting the two fixing holes by half a circle PCD can catch those button location/travel annoyances.)

_________ ___ ___ ___
click on images for larger view
___________Eight 7/8 x 1/4" pieces of steel, 48 Holes, 32 of them tapped 6mm.

__________Not something you would want to poke a finger in, but no worse than a square or natural edge bowl.

 

[Stiggy]

I'm thinking of making some of my own jaws and want to get the recess for the carriers as close as possible to the correct size. I didn't ideally want to judge it solely by eye.

What on earth are you trying to achieve?

Any particular reason for the rudeness Chas? :roll:

Chas, clearly, is not being rude, he was trying to discover 'what on earth' you were trying to achieve in order to be able to help you more. (I know this as Chas is a very helpful man, from what I can see on this forum)

Your original question wasn't too clear which is why I deleted my first post.

Reading text is difficult as you cannot read emotion from words, or, in the manner it was intended. The reader's frame of mind can also influence how writing is read.

"A woman without her man is nothing" - punctuate that - I guarantee it will be different depending on what sex tries!

8)

 

[woodpig]

Your original question wasn't too clear which is why I deleted my first post.

Grahamshed and Chas understood the question fine.

 

[Stiggy]

What on earth are you trying to achieve?

Any particular reason for the rudeness Chas? :roll:

Oh I'm sorry Woodpig, I thought that was the reason for the original misunderstanding...

I'll apologise and leave this thread, catching up on my reading practice.

8)

 

[woodpig]

No need to apologise Stiggy, I value your input.