I have only used a lever 5c collet closer on a Hardinge HLV-H. That was 5 yrs ago and probably my total time on the machine using the collet closer might total 2 or 3 hrs and I did not pay attention to the link geometry or what made the lever stay latched.
I bought some loose Royal 5c lever collet closer parts - enough to make one complete asm and a few spare parts at an auction back in Dec. There were at least 3 or 4 lathes w/ Royal collet closers in the auction and this dummy did not think of operating the levers or of taking images of the closer installations. I am assuming (sometimes a dangerous thing) that the pivot point opposite the handle needs to go overcenter to latch the lever asm. So looking at the Royal diagram: http://manuals.chudov.com/Clausing/C...-Parts-PDF.pdf I am presuming that pivot (at 7) has to travel overcenter with respect to the pivot at (2) and the pivot at the end of link (26). Correct? If not, how does the asm stay latched when the drawtube is under tension from a collet & stock at the far end? I have looked for installation instructions for other 5c lever asm and still it is not registering with me how the system will lock up: https://content.jettools.com/assets/...006_man_EN.pdf https://www.roviproducts.com/wp-cont...structions.pdf
What am I missing?
A couple of images of my parts:

In this image the pivot is (almost) overcenter:
I bought some loose Royal 5c lever collet closer parts - enough to make one complete asm and a few spare parts at an auction back in Dec. There were at least 3 or 4 lathes w/ Royal collet closers in the auction and this dummy did not think of operating the levers or of taking images of the closer installations. I am assuming (sometimes a dangerous thing) that the pivot point opposite the handle needs to go overcenter to latch the lever asm. So looking at the Royal diagram: http://manuals.chudov.com/Clausing/C...-Parts-PDF.pdf I am presuming that pivot (at 7) has to travel overcenter with respect to the pivot at (2) and the pivot at the end of link (26). Correct? If not, how does the asm stay latched when the drawtube is under tension from a collet & stock at the far end? I have looked for installation instructions for other 5c lever asm and still it is not registering with me how the system will lock up: https://content.jettools.com/assets/...006_man_EN.pdf https://www.roviproducts.com/wp-cont...structions.pdf
What am I missing?
A couple of images of my parts:
In this image the pivot is (almost) overcenter:
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