Case Hardening Pinions ?

[islandjj]

Case Hardening Pinions ? Hi I'm refurbishing some gear pinions from an Old Royal Enfield motorcycle. The teeth are fine but the cut outs are worn. I was thinking of building up the metal with a small weld then machining back to the original profile. I'm wondering about the metallurgy, do they need case hardening afterwards , does this affect the original hardness ? will it make then too brittle , anybody tried this or similar ?

Kind regards

 

[Seadog]

Cut-outs?

 

[islandjj]

The cut outs for the pegs on the shaft ( This is an image of one in good condition ) Thanks

 

[penfold]

Can Hitchcocks not supply replacements?

 

[Seadog]

Got it. You'll probably find that the dogs on the mating gear are also worn, all down to poor technique changing gear, but very common on all British bikes of a certain age. Weld will sort the problem but only short term since, as you realize, they are hardened. Case hardening won't really help since they would originally have been through hardened in a salt bath. There are hard-facing welding rods which may have a chance but I know nothing about them, but I'm sure someone here will tell you what's available.

 

[Kent]

Can't see how you can correctly case harden without knowing the parent material and after you contaminate high wear points with weld metal.

 

[The_Yellow_Ardvark]

Those bits in the picture are designed to wear.
That's why they are left softer.
Why are they wearing?

You are advised not to try to harden them, they are designed in a way to allow wear on a consumable part. not pass strees to another part.

 

[Seadog]

I disagree Vark. They wear through sloppy gear changing. The gears are through hardened in a salt bath usually. Just try filing one, you'll see how soft they are.

 

[The_Yellow_Ardvark]

@Seadog
I was always under the impression the teeth were hardened, the insides tempered.
To allow for rough as you like changes, to prevent the teeth from load chipping.

But if you know better I will step aside.

Oh yes, in the old underground workings near Bradford On Avon were they had a place in WW2, you can still find the odd bit and history.

 

[Seadog]

That may be true of certain machines but in my experience, and this is predominantly with BSA, Norton and Triumph gearboxes, I've always found that they are hardened. So we may both be correct

 

[The_Yellow_Ardvark]

@Seadog
Lets agree to have a beer and say yes to each other.
I used to play with Norton's and Triumph in my past, Dad RIP had a Vincent.

 

[Seadog]

@The_Yellow_Ardvark
Sounds like a top idea. If only I'd had the money when you could buy Goldies, Vinnies and Velos for a tenner. Cheers