If you are like me, you find it inconvenient to have to use an Allen wrench to lock and release the tailstock on a Sherline lathe. Four photos in album "Sherline Lathe Tailstock Locking Lever illustrate my approach to solving the problem. The main components are a custom 10-32 screw which replaces the standard 10-32 SHS and a lever assembly. As illustrated in the photos, the top of the custom screw is tapped to receive an 8-32 SHS. The lever assembly is drilled to the body diameter of the 8-32 SHS. When assembled and the 8-32 SHS is loose, the lever assembly pivots on top of the custom 10-32 screw. When assembled and the 8-32 SHS is tight, the friction fit is sufficient to lock and release the tailstock.
Install the assembly on the tailstock and tighten the 8-32 SHS sufficiently to provide enough friction to turn the custom screw until the tailstock is locked, but loose enough for the lever to be repositioned as necessary. This step is actually a series of tighten and release until the tailstock is locked. Once the tailstock is locked, move the lever to a position of about 280 degrees and firmly tighten the 8-32 screw. The objective here is to find a position where the lever is where you like it when locked and yet provides sufficient travel to release the tailstock.
As a small detail, the lever body and shaft are mated via 10-32 threads. The knurled knob is turned finger tight to lock the lever shaft and body to the 8-32 SHS.