Hi Anatol,
I don't think leather would be very long lasting and offer the required drive. I have used the asbestos free friction material used for brake manufacture in the past, its machinable and can be easily bonded to a back plate or drum and is available to purchase online try this site...
Hi,
Just to add my views why not use the Laser engine type valve gear mounted on the rear or the engine crankcase and driven from the crankpin they use straight cut gears that may be easier for you (see picture) alternatively I built an 60 size engine using commercially available skew gears the...