Drilling Crank Spindles
 

Have you ever hollow drilled a cro-mo spindle? Yes, I'm aware of strength issues being compromised. This is a Shimano BB (1988). My Campy spindles are hollow so I'm thinking a good machinist could do this. Has anyone tried this?

I don't think it could be done - the races are hardened and I would expect that would go far enough into the steel to make it un-machinable.

What do you hope to accomplish by this? Surely, there are less stressed spots on the bike where a couple of ounces can be removed.

No, the hardness of the races is pretty thin; if you grind down and polish pitted races, you can get a beautiful finish but the races are too soft. The hardness is gone.

But no, I've never done it, and wouldn't spend any more time considering it than I did just now. It would be an awful lot of work and the odds of success are poor.

Just winter musing. Besides, if Campy and Hollowtech does this, why cant I?

Its all about the tools and process. If you know it and a can apply it, sure you can. Strength may or may not be compromised, depending what strength is needed and if the machining impacts it. Why don't you, for winter kicks, do a FEM analysis and let us know?

I have a machinist locally that has a home shop. Sometime over the winter I'll get this to him and see what he can do.

So what is the orientation of the holes relative to the axle center line?

I think it's been well established that I have a hard time leaving well enough alone, but in this case, I'd leave well enough alone.

expect there would be more weight benefit by going with a ti spindle with pressed on steel races

Not a big deal to drill it if you have a lathe IMO. But why?

Because that's where the pros stash their dope.

Somewhere Laurent Fignon and Louison Bobet are shaking their heads.

???

It is a sign of moderism, I tell ya. Come on you guys, you really cant guess why? :lol:

My Campy spindle on the '77 Colnago is quite hollow. And y'all been using QR's?

Are you drilling along the center line or perpendicular to it? If along the CL then the hole would have to be smaller than the threads for the bolt or is this a different axle? I am thinking square taper.

Most definately parallel to the line of spindle. Yes, smaller diameter than threads.

You have to take the Temper out First Then Re Heat Treat it when you are Done..

I've made nice scrapers out of Metal Files. but I had to make the file soft first, so I could use Other Files to shape it.

if you have a spindle to replace it (just in case), why not try it?

just don't drill your stem or crank arms. B^)

There it is. :)

I agree, give it a shot. If the worst happens and the spindle is no longer useable, not a biggie. Post an update if you give it a try..

OldsCool-

Why not just buy one pre-drilled? Campy, TA and Stronglight made hollow drilled, square taper crank axles threaded at both ends for the fixing bolt.

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Nuff said...


verktyg :50:

Chas.

Why not?

https://c1.staticflickr.com/5/4050/4...081e1eab_b.jpg

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DD

You need a life! Go ride more or find some snow to shovel. :roflmao2: