I was machining some spacers, and wanted an easy way to position them the same depth in the chuck jaws (for machining the parted-off side to length).

Looked at a few over-complicated in-spindle stops, decided that I didn't have time to make one that clamps/locks inside the spindle. So, looked around at my scrap for something to cobble together.


Amusingly, an old tap spindle is a close fit for the Hercus spindle:
IMG_1635.jpg

Mount that in the chuck, ready for machining to spindle bore:
IMG_1636.jpg
(as soon as I get those stringy spirals of swarf out of the QCTP).


It turns out that this spindle nut, er, spigot nut, doesn't have a single parallel axis in it. So, I re-grab in the threaded part (that I will be machining down), to machine the opposite side:
IMG_1637.jpg


then I grab that now co-axial side, and machine the thread away to fit the spindle end:
IMG_1638.jpg

tap it out to M12 coarse:
IMG_1639.jpg


and put it on some threaded bar (that I occasionally use to bolt items onto/into the chuck):
IMG_1640.jpg



I just shoved the bar+brass end down into the spindle, twisted the rod for the correct depth, and pushed the work piece against the other end of the threaded rod:
IMG_1641.jpg


Turning the lathe on will unwind the threaded rod, so I just pull the whole thing out before machining anything.

As long as I didn't twist the rod too much, depth setting seems accurate to about 5 thou, but a few lock nuts help with that:
IMG_1646.jpg IMG_1647.jpg

The long hex thing (a joiner) is just small enough to fit down the spindle. A standard M12 nut is not.
I also used a few of them to make the stop end larger than the bare M12 rod:
IMG_1645.jpg






For this particular job, a chuck spider would have done the job, or external jaws in a small chuck. I also thought about using an old MT3 arbor:
IMG_1648.jpg

and machining a thread or sliding stop into it (like this):
homemade-lathe-depth-stop.jpg

but I suspect the arbor is hard steel, and will be difficult to drill (and/or tap)
Attached Images




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