Anyone got some plans for a tailstock cam-lock?

Pat of TN

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Hey guys. I've been trying desperately to figure out how to make a cam-lock for my Craftsman 101 6x18 lathe tailstock and for the life of me, I cannot figure it out. I can't wrap my head around how to make the eccentric portion push up the piece that goes inside the TS. One problem may be the hole I drilled in the TS is too loose and out-of-round, but I don't know at this point. None of the sites I see about camlocks say anything about requiring a tight-fitting hole.

So, I have decided to throw in the towel and ask H-M for help. Anyone have some ideas, prints, etc.?
 
Hmm... it is a little helpful, some nice pictures. I'm just lost without some dimensions, mainly when it comes to the eccentric portion. I think from those pictures in that thread I'm getting a little bit of info, a better glimpse at how it works...
 
Hi Pat,
I don't have any plans, but I think I can explain it -- it's actually pretty straight-forward...
The main (hex) nut is just a just a length (about 1.5" tall) of 1.25" hex stock. It has a .750" hole directly through the center (up/down), and another .500" hole about 1 inch up from the bottom.
The cam "piston" is a piece of .750 round stock about 1.375" long. This rod has a .500 hole through it .875" up from the bottom. It rides up and down in the vertical hole in the main nut.
The working end of the cam is turned to .500" round (there's no reason the whole thing couldn't just be a .500 rod). The offset section was made by mounting the cam in a 4-jar chuck - offset by .093" in one axis (on center on the other axis). Then a section of the cam rod about 1 inch long is turned down until .093" is taken off one side. This cammed section must be greater than .750" long (it must span the entire wide of the cam piston) and less than about 1.125" (so that the ends can ride on the sides of the .500 hole in the main nut). Grooves are then cut for snap rings that hold the cam "centered" on the main nut.

Hopefully that made sense...

Disclaimer -- I made this a few weeks ago, the measurements are estimates based on the pictures and memory. Hopefully it's good enough to get the idea though...

- - - Updated - - -

One more thing I thought off - the cam piston is drilled and tapped from the bottom. It screws onto the bolt that pulls the locking plate up when engaged...
 
Thanks guys, I've gotten a lot of help from this. I'm gonna give it another try today or tomorrow. Starting to click!
 
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