Drilling Spider Gears

[merjohn]

Can a hole be drilled in the spider gears to make them like the late 31 gears? If so what size is the hole?

[tbirdtbird]

This is actually a good question.

That is technically possible, but it would be way easier to contact Steve at Bert's in CO for 3 that are already drilled.

You would have to anneal the gears (to soften them), then drill them, then the hard part.....re-hardening them properly.

Annealing is easy: heat them cherry red with an O/A torch, then cover them with sand or whatever insulating material you have around, and let them cool slowly. But now the gears are too soft to use.

All the machining to gears is done before they are hardened

[CarlLaFong]

Someone with an EDM could drill them without annealing and re hardening

[CM2]

use a solid carbide bit.dont mess with the heat treatment of the spider,chuck in a drill press,use lubricant and correct speed,feed slowly

[Tom Wesenberg]

For the little bit they turn I wouldn't worry about the hole. I'd imagine many that show wear were abused or run dry.

[merjohn]

Thanks for all the reply's. We will probably just leave them as they are. They show very little wear. The idea came about from reading Tom Endy's instructions for assembling the rear end. His pictures showed the gears with the holes so we were thinking it might be better to do this ours.

[Mitch]

I feel your making a wise choice. They lasted 85 years without a hole

[George Miller]

The hole would only help if you were stuck in the mud or snow, and only one wheel was turing. I agree with the others leave them like they are.

[merjohn]

The experts all agree so we will leave them as is. Thanks!!

[tbirdtbird]

You have made a wise decision. EDM would work but outprice a set from Steve. I myself have never been able to get a carbide bit to drill hardened steel, so I must be doing something wrong!

[CM2]

http://www.atlascuttingtools.com/categories/Drills/Carbide/Carbide-Jobbers-Length-Drills/118%C2%B0-Spiral-Flute-%252d-Wire-Size-%252d-ALTiN/

Im with ya,it takes skill and patience to do whats needed,I have both in short supply..You need a real carbide bit,not some harbor freight special

[George Miller]

It depends on how hard it is. Is it case harden or hard all the way through. Maybe a diamond bit would work.

[Tom Wesenberg]

You have made a wise decision. EDM would work but outprice a set from Steve. I myself have never been able to get a carbide bit to drill hardened steel, so I must be doing something wrong!

When I was in 7th grade I starting making my first motorbike. I tried to heat and anneal a hardened sprocket, but it never softened enough for the drill bit to make a mark. I wound up making a pulley rub on the rear tire. In the 80's I used EDM to make a hole in a transmission shaft, and that worked great.

[CM2]

When I was in 7th grade I made my pulley rub on her back tire..

[tbirdtbird]

So, you made a friction drive bike, the Metz was a friction drive car