ROTEX RM-1 Rebuild (kind of)

[aztoyman]

Pretty sure it's not aluminum so looks like I'm going to have to repair using one of the methods suggested.

Something HAD to go wrong. Projects just don't go this smooth.

One of the cast iron pulleys had a chunk missing when I got it but, it's not causing a problem with the belt. It's for the table feed drive shaft. I thought about using epoxy just to make it look better.

 

[aztoyman]

I was thinking about how to fix the pulley today. I looked through my stuff to see what I had to work with.

I found this chunk of aluminum in the chip tray of my lathe. Hmmm.... it's just about the size I need. So I decided I'm going to see if I can practice making a pulley. Never made one.

 

[aztoyman]

I have a bunch of HSS blanks but I really don't know what I'm doing making tools out of them. So I've been using AR Warner HSS inserts.

So I chucked up that piece of aluminum, faced it off and drilled a hole through it. I found a .500 reamer in the mill tooling I got and reamed the hole to size.

I needed a 1.5" diameter so turned it down to size. Ok now what?

I used the reamer in the hole as a guide, slid the broken pulley on the reamer up against the small aluminum piece in the chuck and steadied the shank of the reamer with the tailstock and a live center.

I loosened up my tool post and lined my cutting tool up to the angle of one side of the pulley flange then slid the broken pulley out of the way so I could cut one side of the new pulley. Did the same for the opposite flange.

Obviously not the best way to machine a pulley but it's working. I went back and forth to get it to proper size because my tool width would start to cut the opposite side at the wrong angle as I increased depth. Once I got the proper angle, width and depth it was actually a pulley. Woohoo. I even test fit the new belt. Holey moley maybe this piece will work.

So I turned it down so it was about the same shape as a single 1 1/2" pulley. I left the top flange a little thicker so I don't break it again. There's room.

I left the main section of the broken pulley in the 4 jaw so I put it back on the lathe to bore a hole to put the new small pulley in.

I basically used what I had. No blueprint. Just measured what I had and made it fit. Totally winging it.

I was going to try a .002 press fit but I was worried that I'd crack it. So I went with .001 and retaining compound. I used a soft mallet to knock it in.

I didn't do it yet but I need to pin it with a roll pin or something.

I think it's going to work. Man I can't believe I got so lucky.

 

[Steve-F]

That's what I'm talking about!! Well done!

 

[brino]

I think it's going to work. Man I can't believe I got so lucky.

From here it looks like it is NOT all luck.

You asked for opinions, you weighed the options, and sure it may have been a new operation to you, but you thought about it and approached it logically.

That's not luck, that's research and design!

-brino

 

[aztoyman]

This is a pretty friendly and civil forum compared to most. I thought I might get flamed for improper use of tooling.

It's not my best work but it worked out ok. Nothing got broke and I didn't get hurt.

Thanks again.

 

[aztoyman]

Well I got back on it today. The vertical motor is cleaned and painted. I need to assemble it. The roller bearings on the shaft are still smooth so I'm running them. I got the vertical head apart and most of it cleaned up. ONE bearing is a little rough feeling so I'm looking for a replacement. The rest feel smooth so they're going back in. Tomorrow I'll post pics of the bearing locations with the numbers for future reference. I have a new over arm support needle bearing I need to install. The original was rusted. Even though it cleaned up I don't trust it will last. I sure don't want to damage the shaft.

 

[aztoyman]

Here's the bearings. The lower one on the spindle is a Norma Hoffman 9020 DD.

The upper spindle bearing is a Norma Hoffman 9017 DD.

The two on the shaft that supports the drive pulley are a pair of Norma Hoffman 6105 PPA.

The one I need to replace is the lower spindle bearing. There is no modern replacement available. I did find one online from www.locateballbearings,com.

I hope this helps any other ROTEX RM-1 owners out there.

 

[aztoyman]

I think I have everything cleaned and painted. I can't really finish until I get the new bearing.

I think it will help my old eyes see the dials if I paint the lines and numbers. Anybody have a good method to do so?

 

[aztoyman]