Ariel Owners Motorcycle Club

Does anyone know what grade of steel was used for the single lobe ramp cam as used for the late singles and possibly what the correct procedure was for hardening the cam.
Thanks.
David

The drawings we have only cover the material spec for 1928 singles. I don't think Ariel would still be using the same material in the 1950s with all the technological developments in the meantime, notably during the war years. On the Square Four camshaft drawing it says: CAMSHAFT. 1 OFF. U.B.A.S. Then there are two notes: CASE HARDEN LEAVING THREADS SOFT and REHEAT IN NEUTRAL SALT BATH. Whether that is of any use to you I doubt but it is all that I can find in the drawings.

Paul
Out if interest, what is the material spec given for the '28 singles?

SG

I would suggest copper plate the threads and use EN 36 A case to a depth of .8 MM and temper to 58 Rockwell. Nev

Thanks for the replies. I have recently obtained a reground hot single lobe cam that was ground by former Brunswick bike dealer/tuner and speedway great Dick Sheard. The cam is ground to a smaller base circle and is asymmetrical. The lobe lift is .411” and the valve timing is near mk1 . I was told the cam was not rehardened after grinding. Unfortunately there is some minor pitting but it is in the base circle, so it is not detrimental. My initial thought was to have the cam nitrided but now I will look at case hardening. Just a matter of finding someone to do it.
David

The 1928 cam material is K.E. 1897, whatever that may be.

EN 39B is the next best These are war specifications but are the best nickel steels for case hardening with the strongest core. Some cars and crap bike ones are only cast iron. Ariel cams are highly loaded and need the best steels and oils to not scuff. JAP motors and speedway motors have rollers on the followers which helps Solid ones are stronger. Nev