Drilling crank pin

iamplanecrazy2 Thu Feb 20, 2014 8:27 am

Could the pin be annealed then re-hardened after drilling?

pkrankow Thu Feb 20, 2014 8:58 am

iamplanecrazy2 wrote:Could the pin be annealed then re-hardened after drilling?

The whole crank would need the whole process. It is too small to do otherwise. it would need protection from scale so stainless foil bags and some paper lining might be needed in the "furnace" or forge.

I have no idea the material other than "steel" so no idea the correct schedule.

Maybe pressing a knurled brass tit into a KB/diesel crank is the way to go...

Phil

Tinker Terry Fri Feb 21, 2014 9:59 am

Wouldn't it be easier to replace the spline? There is already a center hole in the broken crank so it should be a simple job to drill and tap the crank. Mount another crank in your lathe by the rear bearing journal, turn the front bearing journal down and thread it to match. If you cut the thread on your lathe you can make it a slight interference fit and assemble by heating the crank and chilling the spline section. Or make a snug fit and use Loctite.

**RknRusty** Fri Feb 21, 2014 10:35 am

Just watching, this is outside of my skill set. We've got some ingenious dudes around here.
Rusty

PV Pilot Sat Feb 22, 2014 8:53 am

RknRusty wrote:Just watching, this is outside of my skill set. We've got some ingenious dudes around here.
Rusty

lol.
Yes there are.

Been playing around with a x/y table on my drill press. Old factory drill press that I replaced the spindle bearings on.

You could cryo treat it after finish. Had several cylinder liners and cranks done this way with some of my .21 Italian race motors. Was a group buy-in. It was almost like having them super re-chromed,,the cranks didn't scratch at all and I put gallons across them. It seemed to make the ABC liners resist rapid heat changes which allowed us to run leaner needles for more time per tank. Heat gun showed a slower temp climb during race conditions as the tanks leaned/emptied.

Jason_WI Mon Mar 31, 2014 7:52 pm

Travis had a used crankshaft for sale so I bought that basically for the same price as all of the tooling would have cost to drill the hardened crank. In a way I cheated but it will run again.

It will run again - Page 2 929140b1a768528d9336635fc111a984_zps2ab5a66c

It will run again - Page 2 929140b1a768528d9336635fc111a984_zps2ab5a66c

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It will run again

Drilling crank pin

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Replace the spline?

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Re: It will run again