Rebuilding Mark V, GE 1-1/8 hp motor

[DLB]

"Inverted External Snap Ring" I think. But Fastenal only has this for 3/4" shaft, which seems weird enough to call them. McMaster-Carr has them. I'm pretty confident a standard external snap ring will work, at least on motors with the washer for the spring. For the older motors with a cap, I'm less sure how it will fit.

- David

[eagspoo]

I tried squishing the old one before and after installing and it popped off again. Turns out there is a Fastenal just a few blocks from me. I'm a little worried the edge of the groove itself might be worn down a bit and the stock ring doesn't make contact on the sides, so I'll just take the entire motor in and see if they can find one that fits better, makes contact all the way around.

[eagspoo]

I actually ended up waiting for the new snap ring from shopsmith, thinking this was the safest bet but it popped off again. Before putting it back together this time I used a tiny, skinny and sharp file to flatten out the outside edge of the groove on the drive shaft (it was a little rough) because I was worried that was the issue, not the snap ring. It lasted way longer this time to where I actually thought I was in the clear (and was trying out the jigsaw which worked for a beautiful 2 minutes) until the snap ring popped off again.

Even the new snap ring from shopsmith however didn't seem to me to be making much contact around the edges which I think it never does based on it's shape. So maybe I have a little damage to the groove, but maybe getting the snap ring I considered above from fastenal would stay put better? Also am I possibly supposed to secure it with some locktite or another adhesive?

Anyone have any other ideas? I think beyond trying a new snap ring, the only option I can think of is to give up and take it to a motor shop.

[DLB]

No adhesive or locktite, it is meant to stay in the groove under its own tension. You should be using snap ring pliers and not over-extending the snap ring during installation/removal. I presume yes to both. This style of snap ring does not make full contact inside the groove as you observed from its design, but I would think it would take a fair amount of damage to the groove to cause this.

Maybe post some pictures of everything involved? If you have calipers you could check the groove dimensions. For a 5/8 shaft it should be 0.588" diameter and 0.039" width.

I believe the snap ring should be under some tension when installed, the tips should be slightly spread compared to uninstalled. I don't know this dimension, but I can check one with a feeler gauge if it will help.

Perhaps an expert among us can tell us why the designer would have chosen the "Inverted" style of external snap ring for this application. The way I'm seeing it you have nothing to lose by trying a standard external snap ring. The groove dimensions are the same. The standard ring has much more contact area.

- David

[JPG]

The 'designer' originally was accommodating the small width of the depression in the 'cup'.

[eagspoo]

I got a replacement 16mm snap ring off amazon and cleaned up the groove by filing it with running the motor for 30 sec or so. Hasn't popped off yet with a few uses now. Hopefully that is that.

[AustinH]

Just here to say I'm grateful for this forum and this post in particular. After three attempts reinstalling a new factory replacement retaining ring, only to have it pop off, I turned to the forum for help and sure enough, like so many times before, someone had already found a solution. I picked up one each of 5/8ths and 16mm regular external retaining rings at my local ACE Hardware and one of them did the trick. Glad to have my 1985 Mark V back in operation.

[chapmanruss]

AustinH,

Welcome to the Shopsmith Forum.

It is great to hear you were able to find a topic you found helpful.

Although I didn't comment on this one before I would like to now. If you look at the pictures eagspoo post on May 6, 2021, he shows an Internal Snap Ring aka Housing Ring that had been used to hold the parts on the Motor Shaft. What would be better there is an External Snap Ring. An External Snap Ring is made to hold on, as in this case, the outside of a shaft seated in a groove. An Internal Snap Ring is primally designed to exert constant outward pressure to hold in a groove inside a cylindrical housing.

I am not sure why Shopsmith chose to use an Internal Snap Ring on the Motor Shaft but JPG's comment above could be the reason. It is part number 501645 listed as Retaining Ring.

I would have to check but two of the Conventional Headstocks I have, a 2001 and a 2006, probably have the Internal Snap Ring.