Good source for lots of small plastic spur gears?

[777funk]

I'm always working on things and building simple electronic machines for my business. I love automation.

Is there a good source to find spur gears (both single and compound).

Also, is it possible to glue a large gear and small gear, one on top of the other? If not would plastic welding work? I'm guessing the welding could get difficult due to not being able to get in between the two. So I guess gluing or maybe another way?

thanks in advance for any tips!
Nick

[joe61]

If you have an old printer that you don't need, take it apart. There are lots of plastic gears in them, and you can salvage some stepper motors too.

Joe

[Soeren]

Hi,

Is there a good source to find spur gears (both single and compound).

Several, but what pitch, axle diameter, material and such are you after?

Also, is it possible to glue a large gear and small gear, one on top of the other? If not would plastic welding work? I'm guessing the welding could get difficult due to not being able to get in between the two. So I guess gluing or maybe another way?

It depends a lot on what you call plastic.
Nylon is used for many gears and it's very unfriendly to bonding, but why not just mount the two on the same axle by friction - and if more is needed, drill and rivet (when on the axle).

[777funk]

Not particular on the plastic. I know many plastics do not bond well. So that's something to consider.

In this case I have need for one gear with a 1/4" o.d. attached face to face to a 5/8" od spur gear. I've considered trying to drill the center hole of the 5/8" o.d. gear just a few thousandths short of 1/4" and press fit the 1/4" gear into the center. Not sure if that would work. The last detail is the shaft size is .080"

I've looked a little bit and it seems to be a tough time finding those gears. The 5/8" gear would need to be 1/8" thick and the 1/4" diameter gear would need to be long enough to be able to pass through the 1/8" thick 5/8" gear and still have a good 3/8" beyond that for the motor's worm gear to mesh with.

[Soeren]

Hi,

In this case I have need for one gear with a 1/4" o.d. attached face to face to a 5/8" od spur gear.

You don't measure gears in o.d., but in pitch and number of teeth

Take a look at this set. It may be expired, but I have the precise same set from a local hobby shop and Googling "EXPO A26220" should find some.

From the eBay page (which don't give pitch, but this can be calculated from the data they give):

EXPO A26220 - 9 PIECE NYLON GEAR SET
WITH 2mm HOLES
CONTAINS 1 x EACH GEARS
9mm Outer Diameter with 16 Teeth
16mm Outer Diameter with 30 Teeth
22mm Outer Diameter with 42 Teeth
31mm Outer Diameter with 60 Teeth
16mm Outer Diameter with 30 Teeth & 10 Inner Teeth
22mm Outer Diameter with 43 Teeth & 10 Inner Teeth
6mm Diameter Worm 6mm Long
6mm Diameter Worm 10mm Long
2mm Steel Shaft 75mm Long

I've considered trying to drill the center hole of the 5/8" o.d. gear just a few thousandths short of 1/4" and press fit the 1/4" gear into the center. Not sure if that would work. The last detail is the shaft size is .080"

That sounds like a bad idea.
Much better to keep both at an the same axle and then lock them together in some way (bolts, heated needles or whatever).

I've looked a little bit and it seems to be a tough time finding those gears. The 5/8" gear would need to be 1/8" thick and the 1/4" diameter gear would need to be long enough to be able to pass through the 1/8" thick 5/8" gear and still have a good 3/8" beyond that for the motor's worm gear to mesh with.

Check out the EXPO set.