My opinion…….. Long winded as usual!
I think it goes a little further than to just say tailstock locked or unlocked. In my case, my tailstock is loose on the bed and can easily be “cocked†while pushing along the bed. So to say I can get a straighter hole by pushing the tailstock “unclamped†by hand, really depends on where and how much pressure is applied on the tailstock.
Explanation:
In the photo, Fig C and D are the result of the position of the tailstock in Fig A and B.
My photography is poor but Fig C shows that the live center is off to the “right†(enough to cause a bad hole or out-of-round pen blank) while Fig D is centered and will give a good clean hole or a round turned blank.
Again, in the photo, fig A and B show the tailstock sitting loosely on the rail. In fig A, the tailstock is actually cocked to the right and even if pushed by hand in this position will continue to “skew†the hole because the tailstock is at a slight angle to the headstock and any resistance from the material being drilled will cause the bit to wobble back and forth between straight and cocked.
In Fig B, the tailstock is true to the center of the headstock and if I apply deliberate pressure to keep it in this position while drilling, the hole will come out a LOT more centered and clean. But… if I clamp the tailstock down while in this position, it even gives a truer hole.
I think that learning the characteristics of ones lathe goes a long way to learning what causes what, as each lathe is different and there is on one correct answer to a problem.
I didn’t realize how critical the position of the tailstock could be until I recently started drilling on the lathe and noticed slight variations on identical blanks.
That said, once I know what I’m doing, there is nothing in my shop that can equal the accuracy of drilling on the lathe.
I also drill as slow as I can get the lathe to go!
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