Looking for Denso window motor gear

There is a Denso PBT-GF40 window motor that our team acquired (not sure if it was in a KOP or not) but there doesn’t seem to be a coupler for this…

It has a 7 tooth short shaft with a small circular case ridge placed close to the gear and around half the outer area of the gear.

Does anyone know of a coupler that will fit this or a sprocket adapter that will fit this motor and shaft?

I have been searching online with no luck…


There are window motors in the KOP, so it is most likely from there. I did find this 3d printable mount and coupler while doing my own research on using one for part of our robot this year. If you have printing capabilities it is worth a shot I would say, otherwise I am not too sure, I would guess that there is some other type of coupler available, but I do not know where it can be found.

Also, andymark sells snowblower motors, which are the same except for the output shaft. You can buy a 10t or 16t 25 sprocket, or hub to attach to those from andymark as well.

Hopefully you can find a solution!

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If it is the window motor, that is a module 2 gear.

The following file may be useful to you. With the gear info in the file below you could possibly CAD something for it.


we have used the window motors very successfully over the years with 3d printed adapters. We haven’t used them in a few years but I am sure we have the files saved.

What type of coupling do you need it to go to?
I believe we have 1/2 hex in various sizes. As well for the earlier window motors with the plastic star gear output.

If you let me know what you are trying to interface to I can look for the .stl files and email them to you.

Good luck with this… I was very surprised how well the 3d printed parts held up, and we were just using PLA. I am sure it would be very robust in the newer materials available.

Just keep in mind that they might need replacing if used in a highly stressed area. Make sure you can easily access them to do so.


Thanks Bokmeister

That is what I was looking for!

Good luck to your team and hopefully I will see you in Milwaukee at the regional…

Thanks HappyWobot

that is very helpful

thanks Tikitech

Bokmeister hooked me up

No problem! I didn’t realize that your team is only an hour away from us! Thanks for the luck and see you guys in Milwaukee if your there!

Would it be possible if you can give me the file for the 1/2 inch hex shaft. the motor we have uses the plastic star gear output

Sure thing!
Is it for the same Denso PBT-GF40?

Do you just need a straight Denso 7pt star to 1/2" hex adapter?

I believe we have a version that mates with a versa hub as well as a winch spool…

I will have the students get the files to me, for you, once I know your motor model #.

thats the one that we use

I think it would be wiser to invest in this.

My mentor whats to 3d print it. he dosnt whant to buy anything.

I would not feel that 3d print would do well since it is a small female spline.
We could easily print the one I liked from its PDF file…

I dont Under Stand what you mean

The PDF file to the adapter has the drawings of its sizes and lengths…
You can CAD these and print it…

I do not feel like the 1/4" hole where your adapter plugs into would be strong enough 3d printed.

do you think there might be a way to stagnth it

There are so many variables, not knowing the design and load it will be under… I am sure that there is a way to strengthen… usually a steel insert… like the one I linked earlier.


get some hex axle and start filing!!

Have access to a bench top grinder? grind one end square to match the Bosch motor!