diy gear box

[eloid]

I need to design a simple gear box for my steper using spur gears
i need some to help figure out a what gears to use for a simple 3.6:1 and 7.2:1 gear box for my stepper...my math is a bit rusty.... for calculating
this.

below is a picture of what i want, try to make as compact as possible
with out .....running 7.2 gear off a 1 inch gear eg.

[DSL PWR]

Unless you can cut a planetary gear set you will need to use several stages. More stages = more backlash.

[eloid]

Originally Posted by DSL PWR Unless you can cut a planetary gear set you will need to use several stages. More stages = more backlash.

if you use 2 gears to gear down and 3 to drive pinion whats best configuration
and diameter to use? dont know much about gears

[keebler303]

The picture you showed is of toothed pulleys. The belt which connects them is not shown. This is much easier and quieter than a gear setup. It is what I would recommend for a rack and pinion reduction if you didn't want to spend the money on planetary gear geads for your steppers.

If you want to use spur gears, it is the tooth count that matters. So for 3.6:1 ratio use a 10 tooth gear driving a 36 tooth gear. 36/10=3.6

You will want to pick ready made gears if you want durability and accuracy. Boston gear is one option, there are many other suppliers. You need to size the pitch of the gear so that it is strong enough for the loads and fits within your space constraint. Any supplier can give you advice on strength and sizing. Most will list the pitch diameter of the gears. This is the diameter of the point of contact between mating gears. To find the distance between the centerlines of 2 gears:

(pitch diameter of gear 1)/2 + (pitch diameter of gear 2)/2 = dist. between gear centerlines.


Matt