Lathe Tail Stock lock mod

[NodakGary]

Like many Asian 9X20 lathe users, I grew tired of using a wrench to tighten and loosen the tailstock locking nut. The locking bolt is a Metric 8mm-1.25mm bolt 4 inches long. The nearest sized Imperial bolt would be a 4 inch long 5/16 X 20 tpi bolt. The 20 tpi threads are just a little coarser than the 1.25 mm thread (hence more movement per revolution of the nut).
So I replaced the Metric bolt bolt with a 4 inch long 5/16 by 20 tpi bolt and used a 7/8 inch tall 5/16 coupling nut on top. I was satisfied to see it locked the tail stock in place when I turned the nut snug and by unscrewing the nut 1/2 turn I am now able to move the tail stock. I then marked the flat side of the coupling nut that was facing the working area of the lathe and removed the bolt and nut. I drilled an 11/64 inch hole across the upper end of the coupling nut 3/16 inch down from the top and reamed the hole to 3/16 inches to fit a 3/16 inch diameter by 4 inch long nail I am using for the locking lever. After a couple tries to get the bolt rotated properly so the nut locks up the tail stock again with nail/lever fitting closely along the body of the tailstock, I am able to adjust the position of the tailstock quickly and easily.

 

[hman]

Nice solution to a frustrating feature of the 9x20. For me, it wasn't so much that I had to use a wrench as it was that the wrench wouldn't play nice and stay put. Having to retrieve it every time I wanted to lock or unlock the tailstock was time waster.

My solution was to carve a piece of wood that would fit between the top of the bolt and the sloping bottom of the spindle housing. I cut a shallow hole in the top surface of the wedge and glued in a rare earth magnet, to hold it in place on the underside of the housing. It does a great job of retaining the wrench (one end cut off and the shank covered with heat shrink tubing). I can pull out the wedge to reposition the wrench if needed.