I looked at it this morning. It's a long shaft (~6 inches) with a long keyway, plus two circlip grooves between which the variable pulley mechanism sits, all metric. Definitely custom.
In another posting, Gunnar suggested machining an adapter shaft, which could be done, but I don't know that I want to go to the trouble.
Instead, I'm thinking of getting a VFD that's big enough to run this little 1/3 HP motor off one phase when I'm using the little drill press, and this same VFD to run a larger 3-phase (probably a floor model) drill press to be named.
The other issue that's developing in the DP350 is belt wear. The inside of the housing has a layer of rubber dust already, and I've only had the unit since 29 April 2005. I recall some complaints on Amazon about the belts wearing out too fast, and some people saying that they had not had that problem. I suspect that the cause is the sharp edges on the inside of the pulley cones, where the facing cones mesh. The belt is perpendicular to and runs over these sharp edges; this cannot be a good idea. I plan to take the drive apart and round those edges with a hand file. The cones are made of zinc-aluminum die metal.
The belts cost $38 from Delta; while $38 seems a bit much for a belt, I did buy one, to have a backup. What Delta provides is a Tru-Power V13x860.
This was my instinct, but I'm glad to hear confirmation.
The other problem I'm having is large drill bits and countersinks slipping in the chuck. With the original keyed jacobs-style chuck, it was not possible to get it tight enough by hand, so I used a six-inch length of 3/8 black iron pipe as a key extender. This does work, although the key arms were right at the edge of bending, or a little bit over the edge, and the whole operation was pretty time consuming.
So, I bought a Phase II keyless 1-13mm chuck (Travers # 63-099-024, $32) and it's a lot faster, but it too will slip on the larger stuff. I got a surplus spanner wrench that allows me to hold the top (narrow) knurled ring while hand tightening the body of the chuck, and this works for all but the MA Ford 5/8 inch countersink (which has a very smooth shank). There is noticeable added tightening when using the spanner.
I think I'll roughen the shank of the MA Ford countersink with flooded wet-dry sandpaper. It really doesn't need to be polished.
I'm wondering if a better chuck would help. I looked at the ball-bearing jacobs-style chucks, and at the more expensive keyless chucks, such as those made by Rohm. Any opinions?
Yes, but I gather that you have direct experience with this setup, and it works as one might expect and hope that it would. Said another way, there were no surprises. This is often the key.