Ordered incorrect shaft length

So i ordered some maytech 6374 motors with the wrong shaft length for my build and also a keyway 10mm shaft. Has anyone had any experience cutting the shaft length shorter and using an open ended key way on the motor shaft. Cutting the shaft will remove one sealed end of the keway slot if that makes sense. other option is taking the motors to a machine shop and getting a new keyway channel cut. but i think it will cost me alot. Im hoping the grub screw will put enough pressure on the keysteel to stop it being flown out the end of the motor.


resulting keyway slot will look like this.

Super glue the key in place, epoxy it if it makes you feel better. Typically the pulley is very tight with the key installed. There shouldn’t be an issue.


You could always use Loctite RED or Green or whatever the permanent one is, they are used for attaching pulleys anyway. Stick some in, let it dry, then put your pulley on later


Thats what she said

It was not my intention for him to only use loctite. I meant that the key could be secured into the shaft with loctite, and then grub screw and pulley as normal, also loctited in the threads of course.



Well. What else is new :man_shrugging::joy:

Agreed lol

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Tape the motor carefully before shaft cutting, the steel dust will want to get into the motor to make sweet love to the magnets, you don’t want that to happen.


I take it an angle grinder for this is common practice?

Yeah that’ll work. But with great power comes great responsibility. Wear eye protection and secure the motor.

Or use a little baby tool like a Dremel

Hacksaw is another option

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Over here, mate

Have been doing this on 250 6374 maytech motors. Its no problem. The motors is magnetic, so make sure to protect it when you cut it.

Wouldn’t D shaped be “even better” than a keyway for this?

No. Which is why any serious machinery uses a keyway, is stays put, whereas a grub can loosen off and allow the shaft to spin.


What actually happens if you get steel dust in the motors?

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Order your motors from Bioboards along with a load of other stuff and they will probably be willing to help you and cut them for a small fee (offer then 10 euro to do it or something).

Most of the really good DIY suppliers here, haggy, bioboards, pjotr, understand the problem parts of builds and will happily go out their way to help.

The Iron gremlins attack in force.

Or you can cause a motor short, killing your ESC maybe you too.

It’s kinda theoretical we’ve all found bits of stuff on there that shouldn’t and windings are laminated, still it’s good practice, like motor hardening and adding debris shields which don’t cause heating issues

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imagine filling the wires with sand and spinning the motor at 10,000RPM… how long till it fails???
Now imagine you have Sand that is 100times harder and now sticks inside the motor and will not shake loose and fall out with vibration… Now spin the motor at 10.000rpm with hardened stainless streel dust stuck in the wires and motors

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Was this in reply to me? I mean using a D shaped shaft and a D shaped pulley hole. Or hell, a square shaft even.

I can personally attest that this is a valid strategy. I used a sawzall with a metal blade, a key sized for the keyway, and some red loctite.

I used up the blade completely, and the cut was pretty clean.

I’m at 200 miles+ with no issues related to this setup.

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