Bent shaft on Dorian grinder

[Tacomike]

Hello all
I have a older van Dorian 6” bench grinder and the thing runs great. Some how the shaft got bent on one side. Of course my two boys (10&15) have no idea how it happened…go figure! So now I need to replace that shaft and here are my ?’s Has anyone replaced a shaft in a bench grinder and how hard is it to do? And do u think I’ll have trouble finding a replacement for it?
Thanks for any and all help, Mike

 

[rsanter]

Don’t think you can replace it, I think you have to straighten it

 

[larry4406]

Don’t think you can replace it, I think you have to straighten it

If he bends it back say 90%, can you bolt on a sleeve and turn it in-situ like a lathe to restore concentricity?

 

[rsanter]

If he bends it back say 90%, can you bolt on a sleeve and turn it in-situ like a lathe to restore concentricity?

I know that's how prop shafts are generally fixed. You put it in a big lathe and use a bottle,jack to little by little bend it back as close as you can, then you recut the taper. Odds are it needs to be more like 95% straight before turning

 

[Provincial]

On larger electric motors, when a shaft was broken off, we welded a new, oversize blank on that end (tapering the end of the old shaft and the new stub to get a 100% weld) and then turned the new end to size. You indicate in the armature and center drill the new stub so you can support it with the lathe center.

Sometimes the shaft is pressed into the armature rotor. I that case the old one can be pressed out and a new shaft made and pressed in. In this case, if the new shaft can be made of good alloy, it can be more child-resistant.

 

[Tacomike]

Thank y’all for your replies and advice. It looks like it might be cheaper to just find another used one.

 

[Mallen]

There's a trick that works in some cases if the shaft is not permanently affixed to something that will be destroyed by the heat or if you can control the heat with wet towels and heat controll spray and gel.


Depending on how bad it is you might get it mostly fixed just be brute force with a pipe in a vise first. Then you mount the shaft up on a lathe , usually between centers. You get it aligned with a dial gauge on the tool post. Then you heat spot on the outside of the curvature with an acetylene torch until it's cherry red. But don't heat the whole shaft through. The idea is the red hot steel expands more than the colder steel around it. But it's soft and plastic, while the rest is still hard. So the spot you heated deforms to relieve the stress. When it cools, it shrinks and the shaft warps. You then check with the dial indicator and see if it's strait and repeat as necessary.

 

[marinusdees]

Hello all
I have a older van Dorian 6” bench grinder and the thing runs great. Some how the shaft got bent on one side. Of course my two boys (10&15) have no idea how it happened…go figure! So now I need to replace that shaft and here are my ?’s Has anyone replaced a shaft in a bench grinder and how hard is it to do? And do u think I’ll have trouble finding a replacement for it?
Thanks for any and all help, Mike

Most (all, in my limited experience) shafts are pressed into the rotor, and with a big enough press, you can press the shaft out of the rotor. Then, with the same big-*** press, you press a new (straight) shaft in. On the other hand, how big a grinder are we talking about here?? You may not need such a big press.

 

[marinusdees]

Most (all, in my limited experience) shafts are pressed into the rotor, and with a big enough press, you can press the shaft out of the rotor. Then, with the same big-*** press, you press a new (straight) shaft in. On the other hand, how big a grinder are we talking about here?? You may not need such a big press. Need more info?? PM me.

 

[lafester]

Finding a new grinder is definitely the way to go here. You might be able to get something for the remaining parts since those are pretty rare.

 

[rancherbill]

... Of course my two boys (10&15) have no idea how it happened…go figure!

They're innocent. It was your wife who's annoyed at the time you spend with your grinder.

hahaha