Cant see how this can work??

[CRB]

Sorry if I have confused you, not the intention at all.

The point is that you can turn a ring with an inner diameter large enough for your chosen grindstone to enter the jaws comfortably.

The die grinder, or whatever you are using, small router/trimmer, can have a mount machined, since the height, which is adjustable through your toolpost, and the Yaxis is adjustable through the lathe travel.

The two circumferences, inner diameter and grind stone diameter, will only touch in one place, so once both are spinning, the grind stone is moved in/out on the Yaxis until it touches the jaws. It does not really matter where the vertical component leaves the grind stone it will still produce the same end result, trued jaws.

Dead easy

 

[ukracer]

Sorry if I have confused you, not the intention at all.

The point is that you can turn a ring with an inner diameter large enough for your chosen grindstone to enter the jaws comfortably.

The die grinder, or whatever you are using, small router/trimmer, can have a mount machined, since the height, which is adjustable through your toolpost, and the Yaxis is adjustable through the lathe travel.

The two circumferences, inner diameter and grind stone diameter, will only touch in one place, so once both are spinning, the grind stone is moved in/out on the Yaxis until it touches the jaws. It does not really matter where the vertical component leaves the grind stone it will still produce the same end result, trued jaws.

Dead easy

Its not you thats confusing me its the physics mate . lol

My brain cant get a grip of (excuse the pun) of exactly why it does not need absolute precision. If I was gripping on the outside of the jaws i could understand . BUT also appreciate the jaws need to be clamped in the closed direction. That pic of the rpund ring with jaws in it allowing the jaws to pass through a small amount lookes cool and my brain says yeah thats is right. Its just cant follow why its ok if i drill it and I am not that accurate....my fault not yours lol

 

[CRB]

The chuck scroll has to do both and as such is ground to whatever the accuracy standard is. What it does is, in either direction, is hold a cylindrical object 'almost' perfectly. No chuck, though I stand to be corrected, can hold a bar true. Even a piece of ground bar would have run-out, however tiny. You expect to skim everything.

As long as the jaws are all the same distance out from the centre, that is held by a ring, then the inner faces of the jaws will be the same distance from the centre too. The grinding takes the inaccuracies out.

I noticed mine were a bit bell-mouthed when I did my last little job, I suppose I will need to practise what I preach.

 

[MrFluffy]

The ring doesnt have to be accurate to the pins because your not referencing the inner side of it to anything, just using it as a hole to pass the stone through. So if its not centred because the jaws form a circle, it will just move slightly in the offcentre direction to accomodate equal jaw loading.

I'm good at whipping slightly smouldering golf towels out the way if needed. Its stuck in place with neo magnets in the action shot.