Is a grub screw enough to mount a motor pulley?

Whoops! Another measurement I forgot to make… the motor pulley I ordered is too wide for the motor shaft on my SK3. After the motor is installed on the motor mount, I’ve only got 20mm of shaft available for use. The screws of the motor pulley don’t come into contact with the shaft at all.

So, I either order a different motor pulley, or attempt to mount it using just two M4 grub screws. Will that work? I would, of course, create two flat spots on the shaft using my dremel tool.

BTW check out @torqueboards black anodized motor mount; a nice piece of bling! (shown in pic)

if you have filed a flat surface on the shaft and use loctite on the screw and shaft it should hold.


What @lowGuido said. I’m only using a single grub screw to hold my pulleys on. I just dremelled a notch into the shaft where the screw sets in.

If I had a drill press I’d probably drill a hole maybe a 1/4 of the way through the shaft for the grub to grab instead of grinding a slot so that it looked cleaner on the outside.

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@treenutter Just curious, what did that Bling bracket cost you?

@lowGuido product/single-bolt-on-motor-mount-only/

LOL yeah I was asking because I cant access that site. :wink:

@lowGuido oh ha! $75 USD plus shipping

@longhairedboy @lowGuido thx! The other concern I have is that the motor pulley is designed for 15mm belts, but my drive wheel pulley (drive wheel?) is only 9mm, which means I need to use a 9mm belt. Will that be OK or will the belt slip around laterally within the extra space?

so long as the pulleys are square they wont slide around. it should be fine.

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If you can fit the 15mm gears, i’d run the 15mm belt if you can find one!

I have 15mm belts. That’s why that pulley is much longer :smile:

I like the 15mm belts the main downside though is that they don’t work well for any standard RC motors (SK3’s, NTM’s, BigFoots, etc) because the motor shaft is so much smaller. The other downside is the drag especially with two motors but the benefit is awesome.

So next production order unfortunately moving down to 9mm again for the time being. I will have some 15mm options though.

The set screw should be enough on a flat spot but a keyway + set screw is much more safer.

Are those 195mm trucks or 180mm Paris? Unfortunately, I made my bracket too big so they don’t fit on 180mm Paris Trucks with the wheel on.

@lowGuido - Why can’t you access the website?

Thanks @torqueboards! Yes, these are the 195mm Paris trucks. I’ll post pics once I’ve got enough to start a build thread.