Where to purchase internal gears?

Where can you purchase internal gears? I’m looking for either 32 or 24 DP in steel with a face width of preferable more than 1/4" Does such a thing exist or does it have to be custom made? I have already checked Boston, Berg, SDP, and McMaster, none of which have what I am looking for.

How many teeth? Pressure angle?

Stock Drive Products carries some internal gears. Go to their on-line store and search on “internal.”

Rush Gears will custom make them for you, but you will pay through the nose for them.

Are you sure you need them in steel? Boston Gear makes 24DP and 32DP internal gears, 1/4" face width, in brass, with both 14-1/2 and 20 degree pressure angles.

Arrow Gear makes a large assortment of internal gears, up to 17" pitch diameter.

You can also find several more gear manufacturers at powertransmission.com.


I’m not exactly sure of what I want, I was just trying to get an idea of what is available. So, let me ask a few questions.

Can brass be hardened? Also, can two gears accurately be “stacked” to essentially become one wider gear? If so, how?

Last, are there any off the shelf planetaries besides “speed reducers” and drill gearboxes (and AndyMark ones)?

I’ll bet one of our sponsors Al-Craft Industries Inc., can laser cut a couple of them for you. I’ll be the go between of you promise to send them a thank you e-mail.

Send me a DXF line drawing of the gear & let me know the thickness & type of material. I have aluminum, mild steel, high hard armor, & titanium - but the choice will depend on the thickness you need. OTOH, maybe we can lathe them down to the thickness?