I know most guys do belt drive conversion on these, but for the simple folk like me that don't plan on CNC conversion of their mill i wanted to let everyone know there is a metal replacement gear for the Hi/low internal gear on these machines.
Yes its from China... But hey the whole machine is anyway so.. Anyway, i was talking to a guy in Australia that has a few of the Optimum BF20 thats basically the same machine in a different paint color and he put these metal gears in all of his so i ordered one myself. As arrived it needed just a little work on the bore, but thats no surprise because the listing on AliExpress does show that the bore dimension is 16.95mm, and the shaft in these seem to hover around 17mm, plus or minus some tolerance. I just took a flap hone to it and took out a few thousandths and it was a nice sliding fit on the shift shaft.
My top gear, the intermediate gear as most call it, is still plastic to be the sheer/failure point, but at least now the internal gear shouldn't fail. The gears it mates with are metal, so now all the internals are metal anyway, and the top gear is an easy replacement that doesn't take much time if it goes. That same seller on AliExpress also has the top intermediate gear and the brass motor gear as well. I ordered one of the intermediate gears from him since i was placing an order anyway, Grizzly wants $11 each for them plus shipping its almost $21 for a single gear now. The plastic gear is $16 from this Chinese source, combined shipping with the metal gear was cheaper then Grizzly. The interesting part is this plastic gear feels harder and more resilient then the Grizzly original gear, the one that came on the mill from Grizzly has a soft Nylon like feel to it. This gear from AliExpress has more weight to it, so i'm not certain the material is the same, or if its any stronger or weaker, time will tell if i need it, so far my original gear it still fine after a lot of use.
I hadn't stripped out my internal Hi/Low gear yet but i have some projects requiring face milling coming up and that seems to be how a lot of guys have taken out that internal gear running a face mill or fly cutter, so i figured for the price it was worth a shot. The Grizzly plastic replacement is $25.58, so its not a huge difference in price going to a $40 metal gear.
Anyway, just thought i would let everyone know since i have been busy doing various upgrades and mods to my G0704. I mostly mill aluminum parts, bits and pieces for my 3d Printers, and repairing and modifying printers. As well as a custom build i have been working on. Though i have used it to cut some slots in steel plates and that went well, gears survived. I added a cooling fan to the motor housing, and led lighting on the spindle. If i get a chance i will share those parts to Thingiverse that i designed, there's a few similar designs on there but i went a different route with my designs, i like junk box building with stuff i have on hand instead of buying specific parts to match someone else's design.
Grizzly G0704 G0759 Metal Gear Available...
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