Source for Shaft Couplers

Does anyone have a good source for inexpensive shaft couplers? I’m looking to couple a 1/4" od encoder to the end of a 1/4" od shaft for the steering portion of a swerve module. Both shafts will be smooth, no flat spots, so I’m looking for a clamp style (not set screw style) shaft coupling. To allow for some manufacturing tolerances I don’t want it to be completely rigid, so I was looking at using a semi-flexible slit type coupling like this.

At $13.50 the SDP/SI plastic version is the cheapest version I could find. Aluminum versions all seem to be $25-30. Any comments on plastic vs aluminum?

Automation direct makes some (here) for $7 but they’re setup for 6mm shafts. Does anyone have experience with these - do they work for 1/4" shafts, do they require modifications, etc?

Since we’ll be buying several of these I’m trying to find the most economical option that will still be reliable. Any suggestions are greatly appreciated.


While not very pretty, we often couple encoders to shafts using surgical tubing that is zip-tied into place. It works quite well.

I’ve never looked at the cost while ordering these at work, but the company we always go to is Ruland.

There are a variety of shaft couplings here and you can specify which bore sizes you want.

Do you have access to a 3D printer? I’ve had good luck in the past with custom 3D printed couplers for applications like these.


We’ve used these on our 2011 and 2012 robot for our arms/turrets.


Same here.

We use the Automation Direct Couplers that were mentioned on our swerve steering sensor - 1/4" shafts. Just reamed them out. Be careful to not insert the shaft in too far or you will turn them into ridged couplers. A shaft flat can always be filed. Have worked well and the price is nice.

Small Parts Incorporated, they were an FRC sponsor long ago. Now they are part of AmazonSupply.
two of these would work

we made small flats on the potentiometer shaft and the shaft we were mounting on, and used the set-screw version from McMaster referenced above. They worked very well and are easy to install.

We do the same. We got the idea from Dan Katanski from team 240.

In addition, that also is good for dealing with misaligned holes. Trust me, it happens.

Unless you are 254/1114/1538/118/ETC :cool:

Anyone have a picture of how they use the surgical tubing to connect an encoder to a shaft?

Here are two posts containing pictures that I could find pretty quickly.

Right, I know how you’d do it with a trimpot with a shaft on it – you’re basically using surgical tubing as a cheap shaft coupler… I thought we were talking about the kit US Digital Optical Encoders, and thought something somewhat more elegant was going on.

Nothing to see here… :slight_smile:

As you probably realize, the encoders depend on the shaft bearings to keep the encoder disc aligned. Surgical tube will not do that. :frowning:

Ah, I must’ve misunderstood.

I’ve never seen the Surgical tubing method used with KOP encoders, only US Digital S4 series encoders. Though, You could take a 1/4" Pin and slide it into the KOP encoder and then attach surgical tubing to that… Not sure how to address the disk alignment issue though.