D1 Stud Adjustment

[KyleG]

Question for those with camlock spindles: Has anyone had a D1 series chuck that the studs couldn't be properly adjusted on? I.E. in one position, they lock up too soon; twist them out one turn and they lock up too late?

I'm planning on cloning the stud and cam geometry for a latching mechanism. When I read ISO 702 and ASME B5.9, it appears that the cam doesn't have enough travel in 90 degrees of rotation to take up one full turn of thread pitch. Using imperial D1-4 numbers as an example, the the specification calls for .075" rise in 250 degrees of rotation, which is .027" of rise in 90 degrees. This should pull the stud in .042" (.027/sin(40)), which is less than a single turn of the 7/16-20 stud.

Am I missing something? Is this a known issue, and you just let it lock up outside the 90 degree window marked on the spindle? Some wisdom of the masses would be helpful here.

Thanks!
-Kyle

 

[rabler]

My spindles don't have a 90 degree mark, so as long as they tighten down I've not worried about it, that's across three lathes and quite a few chucks. You're ahead of me looking at the spec. Mine tighten anywhere between about 100 degrees and 230 degrees. Outside of that I've adjusted studs. I may be doing it wrong?

If 250 degrees of rotation gives .075 rise, and one thread turn is 1/20" = 0.050, seems like plenty of excess to cover one full turn.

 

[Aukai]

Yes, and I clocked it to the late position(just a touch past), but would not spin when tightened. I'm the resident hack, and it worked, but I don't know any better

 

[Weldingrod1]

Try swapping them in different holes!

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