[DepthOfCut]

Anyone here ever make an 'island' soft jaw where you're holding on the inside of a part, and therefore, opening the vise jaws to clamp the part? We do this occasionally without too much difficulty but in this instance, we keep having to replace the Spiral Retaining Ring. This ring gets destroyed after clamping 3 or at the most, 5 parts. They aren't expensive, maybe $5 each, but it puzzles me as to why we can only clamp this way a few times before it fails and why we've no had this problem in the past.

I'd appreciate any input.

Thanks.

[fizzissist]

Given the Kurt is designed to provide force in one direction and you're imposing the force in the opposite, it's hardly a surprise that components fail.
To be honest, I had never thought of using it that way for that sole reason. What makes the Kurt design great is the downward force component, meaning
on "un-clamping", which is what you're effectively doing, you'd lose that advantage and damage the components not intended to withstand forces in that direction.

Supposing a rectangular hole to be used to clamp for outside machining.....

I don't know of any systems designed specifically to clamp with an outward force, and if faced with a job to hold on this inside shape, I'd mount a parallel
fixed locating bar on one side to provide a fixed Y axis point, a locating pin on the side to locate the X axis, and perhaps a couple of screw-type I.D. expanding clamps with
a parallel in-between them and the part... drop the part on, tighten the screws, and go.

You could also use regular edge or toe clamps, depending on part size or...

In any case, I wouldn't expect good results using the Kurts in reverse.

[DepthOfCut]

All good points fizzissist, thank you. Oddly enough, we've done this many times in the past without incident. I guess our luck has run out for this methodology...

In this particular case, we'll have to figure out something. The island in question is round and we can't clamp it using edge or toe clamps due to the areas we're machining.

[beege]

I've thought of this recently, and have in mind three fingered overlapping jaws that bypass each other as you close the vise, effectively clamping down from inside the feature as you tighten the vise. I've yet to flesh this out, as I haven't had the need for such a fixture yet, but one day I'm sure I will!

[DepthOfCut]

Good idea beege! And you just inspired my solution moving forward. We have a milling chuck(that I'd forgotten about) that we can use for this application. Thanks!

I've thought of this recently, and have in mind three fingered overlapping jaws that bypass each other as you close the vise, effectively clamping down from inside the feature as you tighten the vise. I've yet to flesh this out, as I haven't had the need for such a fixture yet, but one day I'm sure I will!