Locking & Tramming the Tailstock
Tailstock Locks
This type of wrench allows the nut to pass all the way through. Ratcheting direction is quickly changed by flipping the small lever on the wrench. When the nut is loose it will not work the ratchet so I installed a short, strong spring, with washers on both sides, in-between the bottom of the tailstock base and the locking plate. The ratchet now works even when it is loose. Fast & strong method to lock tailstock securely.
I replaced the 5mm set screw. Under heavy drilling, e.g., using a 1 inch bit, the original set screw threads would cut the inside of the groove it sat in. Used an 8mm set screw with the end turned to 5mm. Remove all the burs on the groove edges. I used aluminum anti-seize on the lock & pin. A second set screw keeps the tailstock from rotating if it is over extended.
Die cast Zinc ratcheting locking levers from
MSC (M6-1 threaded bolts) with
a brass washer.
The carriage lock also has a brass spacer that loosely fits the original
counter-bored hole.
A tight fit could possibly bind when it gets grimy. Dissimilar metals work
more smoothly.
For a smoother finish, lock the carriage when
performing facing or cut-off operations.
Taper calculations
One method to tram or center the tailstock is to mount a dial test gauge in the spindle & an MT-2 dead center or better yet, just indicate the inner surface of the tailstock taper. Rotate the spindle front & back while adjusting the tailstock off-set screws (replaced with US manufactured), making half-the-difference changes between them until there are no front/back differences. The vertical top/bottom error was corrected using brass shim stock because mine was low. Use the basic principles of this technique to tram: a micro lathe, a mill, a mill vice, a rotary table or a part.
Shimming or milling the top of the cast iron tailstock base may be required to tram top to bottom.
