Crankshaft repair ideas ?!

[Proxule]

Relax, didn't mean to step on your toes...missed it in the quick glance through on the posts.

I liked your post. I also thanked you for the idea. Im not sure how or what offended you??

Thanks for posting your opinions.

 

[historicalarms]

As nervous as you are about further damage with heat stress, I would build a box big enough for a heat sink for the whole shaft except for the very end that will be welded. Ice water would be best heat sink but water seal around the shaft excit would be a problem so I would probably mix up a batch of mashed spuds or apple sauce that would be easier to contain and put it in the freezer for a few hours

 

[Janger]

Emotions poorly conveyed by posts that were not meant and easily misinterpreted. Assume people mean well. Because they do!

 

[Proxule]

As nervous as you are about further damage with heat stress, I would build a box big enough for a heat sink for the whole shaft except for the very end that will be welded. Ice water would be best heat sink but water seal around the shaft excit would be a problem so I would probably mix up a batch of mashed spuds or apple sauce that would be easier to contain and put it in the freezer for a few hours

LOL All I can think about it my grandfather who would make flavored spirits from fruit and potatoes in the old country.
As the fruit gets warm I capture the condensate and - Whala 2 birds 1 stone. What a ripping idea.

Thanks for your idea and opinion,

 

[Janger]

As nervous as you are about further damage with heat stress, I would build a box big enough for a heat sink for the whole shaft except for the very end that will be welded. Ice water would be best heat sink but water seal around the shaft excit would be a problem so I would probably mix up a batch of mashed spuds or apple sauce that would be easier to contain and put it in the freezer for a few hours

Interesting idea I’ve never done anything like that.
How do you keep steam and condensation from getting into the weld from the heat sink? Is that a problem?

 

[Darren]

You could cut off the damaged part, bore the bearing section and press in a new stub. With a proper press fit it won't go anywhere.

 

[cjmac]

Looking at the picture suggests that there is an extension welded on to the original pulley. If this was used with a belt it would have imposed a radial load out past the end of the crank. If you are restoring this engine will you remove that extension from the pulley? If so, you could perhaps have room for a split tapered bushing. The size of the key is likely determined based on the forces imposed by the flywheel. The forces imposed by the pulley and belt (assuming you put a load on it at all) may be less demanding of the keyway, so you may be able to tolerate a less than perfect keyway.

My Lister (clone) drives a generator via a serpentine (flat with grooves) belt running on the outside of one of the flywheels. I have the traditional flat belt pulley like the one you have but it has never been installed. Diameter is too small for my application.

Chris

 

[Proxule]

Looking at the picture suggests that there is an extension welded on to the original pulley. If this was used with a belt it would have imposed a radial load out past the end of the crank. If you are restoring this engine will you remove that extension from the pulley? If so, you could perhaps have room for a split tapered bushing. The size of the key is likely determined based on the forces imposed by the flywheel. The forces imposed by the pulley and belt (assuming you put a load on it at all) may be less demanding of the keyway, so you may be able to tolerate a less than perfect keyway.

My Lister (clone) drives a generator via a serpentine (flat with grooves) belt running on the outside of one of the flywheels. I have the traditional flat belt pulley like the one you have but it has never been installed. Diameter is too small for my application.

Chris

You need to show me this setup, Sounds useful in power outages!
No that extension is a mickey mouse farmer setup and I have all ready cut it off. That should not have been extended as such.

Thanks for all the ideas guys!

 

[ducdon]

How about turn down the crank. Bore out the flywheel and bush it down to new crank diameter and recut the keyway. Cut a new key seat in the shaft opposite the existing one?

 

[historicalarms]

Interesting idea I’ve never done anything like that.
How do you keep steam and condensation from getting into the weld from the heat sink? Is that a problem?

The weld is all outside the heat sink box (think of a shaft protruding from a gear box). The welded part does suffer the extent of weld heat but the rest (important parts) are kept cool by the mush...stir the mush after each weld to renew cold at the part of the shaft in the box.

 

[Proxule]

Consider turning it down and put on a shrink fit sleeve (ie freeze shaft and heat sleeve). Depending on load it should grip tighter than epoxy.

How much lower would you turn the shaft, Say .100 lower then the bottom of the keyway?
Thanks

 

[Former Member]

Not sure how to answer that one.

Personally I would likely only sleeve the damaged portion and 0.100 below the key (if you have the material) . I would make the sleeve oversized and grind the sleeve to the existing size, then cut the keyway to match what's left.

Its a case of hitting the fine balance of the application.