I really like the way that the DY Engineering NEMA 23 stepper covers tidy up the task of stepper wiring. The only problem is that I like to put a handle on the back shaft of the stepper to allow for manual adjustment. People either like having a handle on the back of a stepper or not, depending on their work-flow.
The problem with the cover is that is sits over the back of the stepper obscuring the rear shaft. I spent quite a while summing up the pros and cons of various ways to extend the shaft and this is what I've come up with.
To extend the shaft I used some aluminium tubing along with some 1/4" drill rod. The aluminium has an internal dimension of 1/4" and is a good sliding fit over the stepper rear shaft and the drill rod. The handles I use are standard Sherline handles as found on their Mills and Lathes.
The extension shaft was made from a 1/4" diameter drill rod. The sleeve is from some 5/16" aluminium tube that has an internal bore of 1/4". The tube was sourced from a railway hobby supplies shop. The sleeve is a nice sliding fit over the extension shaft and the stepper shaft.
The dimple in the sleeve was done with a punch while the sleeve was placed over the stepper motor back shaft. The purpose of the dimple is to stop the sleeve sliding past the end of the D flat in the stepper shaft.
This photo gives some perspective on the length of the extension shaft as compared to the stepper rear shaft. The length of the extension is 28mm although the length depends on the shaft handle that is to be utilised.
The epoxy chosen was loctite 3805 which is a two part filler epoxy for steel an aluminium. I chose a filler over a glue as it is more viscose and has less change of running and ending up in the stepper bearings.
The two photos below show the results of the gluing job. The epoxy has a work time of about 5 minutes. I put some epoxy in the end of the sleeve closest to the motor, and slid the sleeve down until the dimple seated. I then put some epoxy on the extension shaft end and slid it into the sleeve.