From: muratlanne@gmail.com   
      
   "Clare Snyder"  wrote in message   
   news:90c5djpacm2j9ob6qjt6dhthcnvqab1e87@4ax.com...   
      
   Any of you guys have experience with timing belt drives? I need as   
   compact as possible 1 1/2:1 reduction from a 600 rpm  2.5HP engine   
   (3600 crankshaft RPM with 6:1 reduction) then another 1 1/2:1 after   
   that (so lower speed higher torque) ( total reduction 13.5:1).This   
   will be driving a 20 inch diameter 2 inch wide tire/wheel.   
      
   How wide and how large do I need the small sprocket? For simplicity I   
   would likely like both stages identical. This simplifies everything   
   including tensioning   
   Small sprocket on output shaft  driving large sprocket on jackshaft   
   turning small sprocket driving large sprocket spinning on output shaft   
   of the engine/gearbox  with wheel attached to that sprocket. Distance   
   from center of small sprocket to outside of large sprocket cannot   
   excede 7 inches.   
      
   Is this possible/feasible???   
      
   --------------------------------   
   I've designed only vee belt drives. Drive belt manufacturers provide   
   detailed design information on line, which I studied after my guesses with   
   parts already on hand failed. I hadn't adequately accounted for the high   
   peak to average torque ratio of a one cylinder 4-stroke gas engine.   
      
   Vee belts have the advantage of being able to slip by engaging the idler   
   clutch pulley gradually, to accelerate from rest. On my bandsaw mill the ex-   
   motorcycle wheels need several seconds to get up to 60MPH. The $99 HF engine   
   may stall during engagement unless running about half speed.   
      
   On an old Maytag washer the vee belt slips for quite a while as the drum   
   spins up to speed in the rinse cycle. It's a special belt, a standard one   
   with exposed rubber grips too tightly. The motor slides against springs to   
   let the position of the separately driven water pump control the drum belt   
   tension. Pushing the motor inward to loosen the belts reduces its starting   
   current surge to let a 3KW generator run it.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)