Crank Shaft ABC Motorcycle information

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5 years 2 months ago - 3 years 11 months ago #748 by Peter Gillespie
Crank Shaft ABC Motorcycle information was created by Peter Gillespie
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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Last edit: 3 years 11 months ago by Peter Gillespie. Reason: duplication

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5 years 2 months ago #751 by Peter Gillespie
Replied by Peter Gillespie on topic Crank Shaft ABC Motorcycle information

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?
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5 years 1 month ago #761 by keithsams
Replied by keithsams on topic Crank Shaft ABC Motorcycle information
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

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5 years 1 hour ago #786 by Peter Gillespie
Replied by Peter Gillespie on topic Crank Shaft ABC Motorcycle information
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
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5 years 1 hour ago #787 by alex
Replied by alex on topic Crank Shaft ABC Motorcycle information
Splendid stuff

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4 years 11 months ago - 3 years 11 months ago #812 by Gillespie
Replied by Gillespie on topic Crank Shaft ABC Motorcycle information

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
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Last edit: 3 years 11 months ago by Gillespie. Reason: Spelling

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