A current job is machining the castings for a Harrison M250 lathe fixed steady.
I have an original genuine one to copy.

One photo shows the original Dia 27 spotface for the lathe way clamp M12 bolt.
The other photo is the setup on the mill to drill the Dia 13 hole, and a 1/2" boring bar taking 1/4" square HSS bits.

My plan was to grind a bit and use the quill to pull up against the casting.
Not really successful, but it was only a tentative effort.
The bit stickout is 7 mm, and the casting has a hard skin.

I am thinking of swapping the bar ends and use the angular bit holder.
Grind a bit with, say 0.5 mm tip width, then set at 7 mm stickout, and take a cut.
Then reduce stickout to 6.5 mm and take another cut.
Then repeat the steps to get the skin off.

Then repeat original square effort to make flat and finish off.

Counterbore Setup compr.JPGOrig Counterbore compr.JPG

Any other suggestions ?

Keep well,
John.
Attached Images




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