Crank Shaft ABC Motorcycle information

I am about to start the Crankshaft Manufacture .
Before I start I would like to open discussions about this. Some Members have told me about a Crankshaft that was made in sections and Press assembled afterwards. There has been discussion about the materials of manufacture and the Hardness.
There has also been a lot of discussion about the offset on the Sopwith ABC. You may know that the Barrels are offset by 12.8 mm while the center line offset of the Connecting rods when fitted to the Crankshaft is 19.8 mm . This means at best the Connecting Rod is never under the center of the piston , it is off center by 3.5 mm at least.
Please help me by discussing all these and other issues so that we can manufacture after having been mindful of all the issues.
I recently purchased a whole lot of ABC parts NOS and I could not believe my luck when I found an original Forged Crankshaft that has never been machined. This Must be the only one in the world.?



Regards Peter
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This is the test Certificate for the ABC Crankshaft . The Crank has been hardened to 57 Rc while the forged blank is only 20 Rc. I suspect they carburized the Crank to achieve the Hardness so I have sent the Forged Blank for testing as well. Any comments?

hi peter
I am sure you are going in the right direction and we have 100 years more knowledge and I am also sure your crankshaft will be running in 2120 that's if you can get petrol

Hi , We have had the forged crank blank tested and the results are as expected. EN36A is the closest equivalent. We can achieve the hardness we need by Carburizing. Keith is also correct, with modern lubrication we will all be dead before this becomes a problem, but we are going to get it right anyway , just because we can.
Regards
Peter

Splendid stuff

The ABC Sopwith crank seems to be machined from a forged blank while the ABC Gnome Rhone appears to be machined from a large diameter solid. We will probably machine the new Crankshafts the same way as the French did as we do not have the forge blanks. See photo