[Bob Carriere]

Hi Jack

Those tires were cut with a hot grooving tool. Something like the old fashion electric soldering iron with a very thin U shaped blade..... it would stink like hell but it moved through rubber like the proverbial hot knove in butter. There was a guide plate that allowed adjustment/control over the depth of the cut.

The sipe cuts.... not even sure fi that is the wirte spelling.... was done by mounting tires in a special jig and the cutters were a gang of very thin rotating blades arcing around the tires at some 45 degrees.... it would make about 6 to eight cuts per pass...... much like the Michelin ice tires they now sell...... the cutters were guided over the whole diameter of the tire.

I believe there was a recapping facility in Ottawa in the 70s that had such a sipe cutting machine..... I know they also regrooved recapped tires for buses at one time.



Cheers