Cam shim, is it made of anything special?

[1340evo]

Yet again, my engine builder let me down fitting a .060 cam shim when it should be a .065 to get it in limits...

Do we think these are made of anything special or maybe heat treated? the one I have is as rough as a bear's ass on the bore and OD, but is ground flat on the thrust surfaces.... It's magnetic but could it be some kind of carbon steel or just std Mild Steel?

None in the UK I can find so making is my only option 

[1340evo]

It's okay, I found a Estern kit with 10 shims in .050 to .100... £12.00   

[Hillside Motorcycle]

Mild steel, probably 1018.

[1340evo]

Bought some, but the .065 I wanted measured from .065 to .059 !... so just punched out crap really.
Have surface ground the .070 down to size..