Found damage with my vari drive :-( Need advice.

[G-ManBart]

For the motor pulley with the wollered keyway would braze hold up the the use? I could weld but that will input a lot more heat and be harder to machine out. If I use braze I could just use a square file to clean up the key way. I know I could theoretically do the same with weld but it’s going to be a tight hole and suspect the weld is going to make a mess in the hole and be harder to file.

If welding is the route I need to take I was thinking about using the lathe carriage for slotting the keyway. I’ve never done that operation before though. It’s also kind of a long section to slot and feel like I might get some deflection on the hss blank.

Its hard to tell from the picture but the keyway is pretty bad and the shoulders are far from 90*

Edited to add reference picture to the pulley in question

Any reason you couldn't just put a new keyway 180* opposite the old one? I would still try to weld/braze the crack closed, but that's going to put a lot less heat in that filling in the entire keyway.

 

[D.sebens]

Any reason you couldn't just put a new keyway 180* opposite the old one? I would still try to weld/braze the crack closed, but that's going to put a lot less heat in that filling in the entire keyway.

I’m a little intimidated at making a keyway from scratch. I also felt like it would double the weak spots. I think I’m going to try brazing the pulley with the worn out keyway. I mean the key is plastic coated and the bushings are plastic. I feel like if it’s all tight it should be fine.

The crack is on another pulley. I was thinking I’ll just put some braze in it. I haven’t brazed in years but I’m sure it’s like riding a bike right…..

 

[D.sebens]

Well I bought all the Bridgeport keys to find what’s closest.


One is .25” and all plastic. That one goes to a 1.5hp. The next one is .375 and goes to the 2hp. The last is .312” and goes to the front driven pulley. Since I had a loose 1/4” keyway I decided to try slotting to 5/16” to use the 3rd key. It turned out okay. The slot depth is even in front and back, when the drive key failed it chewed out a lot of material. I’m not filling in the missing sections it will just have to live with it. I will have to grind the nub off the key and drill and tap for a keeper screw.

Man cutting the braze was miserable. I’ll have to adjust the carriage gib/holders. It definitely loosened up a bit!

 

[D.sebens]

I was wrong about how uneven. I ended up finishing it with a file. The machine is too weak to chisel at it with full contact. File took 15 minutes to get there.

 

[Mheaton92]

Can I ask what kind of mill it is. I have a box full of brand new parts for a sharp/Alliant mill.


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[D.sebens]

Can I ask what kind of mill it is. I have a box full of brand new parts for a sharp/Alliant mill.


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It’s a Hartford mill. I don’t know much about the clones and what they share with other machines. What parts do you have?

 

[D.sebens]

It breathes again! Just a minor overhaul ! The pulley shaft thing seems to be working fine. There’s alittle bit of noise in the spindle at high speeds but it feels smooth at the spindle. It moves through the speeds fine. Sorry for the angles of the video. I was too excited to think about framing the video.