Bill -

Converting the drill press to the twelve speeds involves an idler pulley that mounts between the two existing pulleys, a replacement for the rear pulley and two new belts. This was a Rockwell/Delta accessory that I doubt is available any longer. You might find one on Ebay, but I'd bet it would be pricey. As noted speed changes can be a bit difficult with this setup. I wouldn't worry about it and just use the four speeds you have. Getting a replacement motor with a slow speed option (1,150 rpm instead of the standard approx 1,700) might be a better expenditure as it would give you a slower low speed which is helpful for larger bits. You'd sacrifice some high speed but it would still be high enough to spin small bits for woodworking.

You might try to find a table raising accessory so you can crank it up and down, as adjusting the height of the table without this feature is difficult. You could try to find the Rockwell/Delta accessory for this but the same rule applies as above. Instead, I got a drill press table raising accessory from General as it was half the price of the R/D and much more substantial. You could get any make table raising accessory so long as it matches the diameter of the column on your drill press. Also as noted by others, with the 6" quill travel raising and lowering the table becomes less of an issue.

Good luck with it and enjoy. Be sure to post some pictures when you get it cleaned up.