[senor J.]

does anybody know of a good source for a zero backlash (or close to it) gearbox reduction unit? say about 20 to 1 ratio. Im looking for something premade to use with a rack and pinion setup and dont want to go to all the headache of fiddling with a bunch of gears to get the correct reduction. I'm not a machinist. Thanks in advance.

[Al_The_Man]

If you have time then ebay is a good source, I have picked up several this way, some with motors attached, here is one project http://www.cnczone.com/forums/showth...15&page=3&pp=5
Bayside is the most common make that comes up. Just a couple of months ago, a seller in Cal. was dumping around 40 Bayside planetary boxes for around 5c on the $ brand new.
Al

[senor J.]

planetary gears eh. havent had any experience with those. how good are they with torque? I looked on ebay today and only saw some small ones that I dont think would provide the torque needed to move a 100lb gantry 250 ipm~ are there bigger such planetary gear boxes available?

[Al_The_Man]

The one's I showed in the forum link operated a plasma gas cutting tables, the gantry's weighed around 300lbs, I have seen smaller ones used on some large manufactures tables. You can get the torque figures from most of the box manuf. web sites.Bayside for e.g.
The bayside series I used range from output torque of 300in-lbs to 8000in-lbs with a peak output of 498in-lbs to 15000in-lbs. The standard backlash is 10arc minutes and the low backlash is 5arc-minutes. Max input speed 4000 rpm. 85%eff. The input spur gear is sized to the shaft of your motor, and the spur gear is clamped by allen-screw.
Al