Hi @johnconroy John
I've been studying your design - I'm thinking about making one too. I notice yours is perhaps 2.5" wide. Has that proven to be wide enough? Any tendency to rock? I always overbuild.
I see there is a pocket in the side rails at the bottom - was that already in the source stock?
It gets clamped down to the mill table and the side plates taper from 1/2" thick at the top to more than 3/4" thick at the bottom. The pieces are bolted together at the bottom with three 5/16" bolts and 4 at the top so there is no flex or tipping possible. The source of the steel was old railway track plates that hold the rails to the ties (like in the attached picture). I bought 3 of them from a scrap dealer. The square holes were in them for spikes to pass through. I didn't harden the center but nothing turns against it so I didn't think it necessary.
Thanks for posting those pictures. One the second tail stock/foot stock Kevin - is the quill threaded inside the block? and at the left end there is a bolt at the quill axis - does that go into a keyway on the quill?
Why is the dead center point at an elevated axis that the middle? Maybe allows machining on the end of the part without interfering with the cone? (kind of like those slim nose cnc live centers?). Inquiring minds need to know!
@kevin.decelles There is some subtle magic on the Shars quill. I like that design. I don't quite follow how the nut handle moves the quill back and forth. Turning the knob would just move the threaded bolt/nut part in and out of the quill unless it is held in place somehow? The BB one has that notch which pushes the quill back and forth with the nut rotation. I don't see how that works on the shars one?
Interesting diagram Johnwa - seems to show more detail. Thanks for locating this. It's still a little hazy to me how the quill action works.
Part 60 & 61 have to be held in place in line with the quill to push/pull the quill. That could be done 3 ways maybe. With A) set screw 55 sliding into the groove on 61, B) with a roll pin Kevin mentioned in the end of the holder - two small holes circled - pin going into the groove on 61, or C) with set screw 52 somehow but I think that just holds the knob 25 on to 60/61.