"Jim Wilkins" wrote in message
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"PrecisionmachinisT" wrote in message
news:HPWdnYy4cbr10c_PnZ2dnUVZ_qadnZ2d@scnresearch. com...

I would never disconnect the spring, it's not going to provide any
positive benefit even when tapping and it's also very annoying having to
unlock the quill with one hand while having to also simultaniously use
the other hand just to keep the tool from suddenly dropping down into
your work.

I suppose if a person had three hands then if might not be quite as bad.


I drill and tap on a Clausing mill that lacks a return spring, which
trades one set of annoyances for another. Having the tool slam onto the
work is considerably worse than having it rise when released. I replaced
the plastic ball on the quill feed lever with a brass one heavy enough to
counterbalance the chuck, and tighten the quill lock just enough that a
drill bit has to be pushed through the bottom of the work. Mine is the
early model with one hex bolt for the quill lock.

Ball-bearing Jacobs chucks usually grip taps well enough to start them
straight in the hole before switching to a tee handle. Resting the chuck
jaws on the cone at the end of the tap gives some indication if it
wobbles. I suppose I could hang a weight on the quill feed to make the
chuck jaws push and center the tap while I turn the tee handle with equal
pressure from both hands. A few times I've loosened the chuck so it only
guides and started the tap with a wrench on the upper end of the flutes.
This area can be ground flat a little to give the wrench a better grip. I
don't grind past the thread roots to avoid weakening the tap.


If I'm going to hand tap, generally I put the tap into a tee handle type
wrench which has a center hole at the end opposite the tap, then I'll spring
loaded center in the drill chuck to guide.