This is the late early 50's this guy would come round asking if there was any knives that wanted sharpening, he had a pedal cycle with two seats on it ,one seat mounted on the handlebar stem and facing towards the back of the bike,a big black painted stand lifted the back wheel off the ground,and attached to it was a big spring, the other end of that was a grindstone,also on a swivel bracket, arranged in such a manner that when the stand was pushed down raising the rear wheel of the bike off the ground,the grindstone was pulled down onto the back wheel tyre. he would sit on the reverse mounted seat facing the back wheel and sharpen the knives on this grindstone, by pedaling the back wheel, he would do up to twenty knives for 6 old pennys.....a blast from the past..... Jack.