This is my first post here, and I wanted to contribute to this thread with what I’ve learned in dealing with this same issue. I have a broken DP350 and the new Renovo part in hand. (After writing it out, I'm going to split it into two posts; one for repair and one comparing the two pulleys).
Some years ago, I thought my drive pulley had exploded, and found the Renovo part coming soon; but after checking back every few months, I gave up and forgot about it. I discovered the other day when cleaning bookmarks in my browser that the Renovo part is finally available, so I ordered one and took apart the stock one which had been sitting here in the unused drill press all that time.
When I took my old pulley apart, I realized that it hadn’t actually broken, but that the steel sleeve was simply floating in the top pulley and so the pulley came loose and was just oscillating randomly up there. The teeth are a little bit beat up, but I’m surprised it’s not in worse shape than it is.
I couldn’t find a way to re-fix that sleeve in place (nor see how it ever had been – I found no sign of a rolled pin), so I decided to drill and tap a hole for a ¼-20 set screw I had available. I was able to tap the hole, but I cracked the flange when I first tightened the setscrew, so be careful if you go this route. When I reassembled it and ran it through the range, the pulley came off the sleeve again; to make sure it would stay in place, I ended up drilling through the tapped hole, and drilled a locating dimple on the sleeve itself. I then repeated that on the opposite side with a second set screw.
To locate the sleeve, first move the belt out of the way, install the bottom pulley in place, then place the sleeve onto the shaft and let it slide down until it rides on the bottom pulley. Then slide the upper pulley down onto the bottom pulley making sure it meshes completely. The sleeve will sit proud of the top pulley by a quarter inch or so, and that’s the position it needs to be fixed – without some of the bushing protruding from the top, the tension spring will sit at angles. When adding set screws, you can drill and tap the set screws first, but DON'T drill locating dimples in the sleeve until you can assure that the position is correct, and the two pulley halves will mesh in that position.
After a bit of fine-tuning, and new set screws on opposite sides of the top pulley, mine is working again with repaired stock parts. If you have the same issue with a loose sleeve, I'd recommend trying this fix. The hardest part is ensuring the two pulley halves will align and mesh, once the pinned sleeve is fixed in place, and that just takes some patient fine tuning.
If your pulley is completely broken and is not repairable, the Renovo pulley may be your only option, and there's more info on that item below in the next post.
