[damae]

In my retrofitting of a Series I Bridgeport, I have discovered how expensive timing belt pulleys are! For instance, I need two 18 tooth and one 26 tooth pulley, both H-series (.5" pitch) and 1" wide. Here's what I ended up spending:

16H100 $38
26H100 $60

I cheated by using metric size pulleys (38.0mm bore) that aproximate the correct Inch size (1.500"). If I ordered the correct Inch size, the cost soar to about $175 for those two pulleys!

And I ordered them with a simple bore, no set screw, no keyway, just a stright hole. I reason that these aluminum pulleys represent about $2 of aluminum (at the most) and perhaps 10 minutes of machine time on a 4 axis machine. So it seems like a part ripe for DIY'ing! What do you folks think?

I already blew $100 on those two pulleys and discovered I have need for several more of them, of various sizes. What is the simplest and most cost-effective way to build these? Can it be done easily with a 3 axis machine?

Perhaps I could use an indexer and cut one tooth at a time, manually indexing to the next tooth? I don't mind if this takes an hour or two to make a gear. Would this indexer do the job?

http://www.use-enco.com/CGI/INSRIT?P...&PARTPG=INLMK3

I'm sorely in need of some machining advice on how to do this. My gut feeling is that the best way to do this would be to simply use a 4-axis machine. But I'm kind of up against a boot-strap problem; I need the new pulleys to make my 4th axis.

Actually, I will be hobbling together my 3rd axis pulley too. Hopefully that one will last long enough to help me machine its own replacement!

So please chime-in and offer any comment you can. I'll take it all - from hair-brained idea to tried-and-true techniques.

Thanks in advance!