How do I do this?

[TomG]

Hey Wong,

The obvious way would be to make the bushing, less the keyed hole in the end and then machine the key on the rotary table with a small end mill.

Another option that would result in a functionally equivalent part would be to make the bushing and machine the bore straight through. Then make a mandrel with the two flats, insert it in the bushing and squeeze the end of the bushing on the mandrel with the mill vise to generate the flats. You might then need to take a clean-up cut on the O.D. of the bushing to remove any raised areas where you upset the flats.

Option three would be to make the bushing less the keyed hole, lay out the key shape in the end and file it to shape.

Another option would be to cut the keyed hole using a custom ground slotting tool like I used to square up the corners of slots on my Steven's Favorite project.

Hopefully these suggestions will get you started in the right direction.

Tom