Grow a pair!

I designed the new X axis ballscrew ends with an M12 x 1.5 thread (aka one of the "metric fine" pitches). Don't recall why, but that's not the point. What is the point is that I don't have any nuts that size, nor any taps. So I ordered a spiral flute tap (YG-1 brand) from Cutwel that should arrive tomorrow in the post. Before I can use it, I'll need to make up a couple of nut blanks.

Got some nice looking hex bar some time back in Canada. Seems like the local equivalent of our EN1a ie cuts like butter and leaves a very nice finish. I used it to make replacements for some of the large bolts on the Blidgeport. Looks spot on in terms of dimensions for this job which is handy, given that I don't seem to have anything else to choose from.

This first nut is what secures the hand wheel on the RH of the ballscrew when there is a power feed unit fitted. Due to the additional length of the bevel gear drive, this nut has to extend into the bore of the handwheel. It comes with the power feed unit. So it needs a reduced section as shown. I've just copied the length of the shoulder it by eye, by holding the original alongside. The original has a different thread obviously - some sort of Mercan pitch (UNF?).

It's sensible to chamfer the edges before parting off. I'm using the Korloy KGT parting / turning tool here to chamfer this one and the start of the next one at the same time:

And at the other end of the ballscrew is a plain nut. I've just chamfered the end here. The through hole is the tapping drill for M12 x 1.5 ie 10.5mm.

Here they are. Original Mercan nut at the left, New blanks alongside. Ready for threading.

There.