When Pete ( 10K Pete ), put up some pictures of his neat slitting saw arbor not long ago, it reminded me that I needed a 1/2" dia. arbor for a few nice slitting saws with side as well as peripheral teeth that I bought on a stall way back. ( Got plenty of 1" bore saws and an arbor that I made in the distant past..., but I couldn't use the smaller bore saws. )
Decided against the configuration used by Pete, as the 1/2" size meant that the cap screw dia. to secure the cutters would be a bit on the small side. ( I see that one of the Chiwanese suppliers does offer a 1/2" bore arbor done in this way, with stepped washers up to the 1" size - apart from the objection above, the drawbar thread size is metric, and I'd as soon stick with the 3/8 Whit size as per most of my MT2 kit ).
So, this arbor is just done in the usual design, with a 1/2" BSF thread on the end nut. Screwcut the internal thd. about 80% depth to take the meat out of the tapping operation, and finished with a tap.
Don't know what the convenient chunk of bar for the main component that I found in the scrapbox was. It turned well with a fine cut, but work hardened and was a bit of a pig when I wanted to get the metal off with a decent depth of cut.
Didn't have a suitable die, so screwcut the external thread.
Re. the other odd pictures, it was nice to use the Tom Senior dividing head for once, as it suited holding the MT2 taper. As I can't transfer chucks from the Myford, it doesn't see much application. I picked up some simple collets to fit the taper at the Guildford show, so might get to use the head a bit more...
Dave
