Should I split the collar?

[raferguson]

In the course of repairing my old RV, I found that the slide motor that I had was no longer available. I bought another slide motor, but it has 3/4" round output shafts instead of 3/4" square outputs. There is a fair amount of torque involved in moving a slide. The old 12V gearmotor was tagged as 58:1 gear reduction. Figure output of maybe 5 rpm.

I was planning to make an adaptor; take a few inches of 1.25" steel, bore one end for the shaft, and then mill a 3/4" square on the other end.

The 3/4" shaft has a hole for a 1/4" bolt. I am concerned that the shaft might move inside the adaptor, especially since my machining skills are limited, and it is certainly not going to be a press fit. Should I take the adaptor and cut a slit in the round end, such that the bolt will clamp the adaptor onto the shaft? I have attached a sketch.

 

[benmychree]

It certainly would not hurt to do the slit, however, I'd carry the slit further back so that the bolt could more easily contract the hole tightly in the shaft.

 

[savarin]

is the hole going to pass through the shaft?
yes - ok to slit as benmychree states
no - dont slit else the bolt will open the slit and loosen the fit

 

[Eddyde]

IMHO, try to get as tight a fit as you can and not do the slit. But if you do go that route, I'd cross drill a hole at the end of the slit to eliminate any sharp corners that might promote cracking.

 

[Doug Gray]

Get the best fit possible and use a roll pin thru... and forget about it.