Crankshaft Repair

The crankshaft was broken right against the crank web, being a drop forged steel crank this was not a real problem, just time consuming.

This is how my mate, John Hartley, carried out the repairs to my crankshaft.
Firstly, the surviving shaft was placed into the lathe and aligned perfectly. The damaged area was bored to suit the new shaft, but also he bored a smaller diameter hole into the shaft being held in the chuck. This is the start of replacing both crankshaft arms.

Broken Crankshaft

You can see here that the locating hole has been drilled and now crank web bored to suit new rough machined replacement shaft.

* NOTE: the jacking bolt between webs to strengthen the web while drilling and boring. This bolt stayed in place during the whole process to prevent flexing or movement.

Boring web and locating hole

Crank web bored"C", locating pin made "A", new crankshaft rough machined "B"

Locating pin "A" goes into "B"
"A" is then pressed through web and onto locating pin. The shaft is then brazed and pinned into place.
First shaft in place, second side ready.
Both finished shafts in place, brazed and now being pinned for extra strength.

The centre piece on the above photo was then removed, after brazing and pinning, by cut-off saw and ground clean.

Keyways cut and shafts machined to final polished finish ready to fit flywheels.
Various steps machined on shaft and rust proofed.
Finished Crankshaft, with big-end ground
Big-end surface ground, view of jacking bolt.
Timing gear key fitted, timing gear cleaned up and then fitted.
Now to move on to pouring the white metal (babbit) bearings.