philwillmt
You're right, the pitch diameter of the pinion gear is outside diameter minus approximately the full height of 1 tooth. . A 2 inch diameter shaft with teeth cut 3/8 deep would give you a 1.625 pinion pitch diameter . Multiply pinion pitch diameter by pi (3.1416) to determine ram travel for 1 revolution of flywheel. The spur gear I used on my homebuilt splitter has an outside diameter of 2.833, & a pitch diameter of 2.500 inches. That difference in pinion pitch diameter compared to SS, DR, SpeedPro, et al, is why I run mine at much lower rpm. 2.5x 3.1416=7.854 inches of travel per revolution of flywheels. Doesn't take long for ram to go 25 inches at 160 rpm at that rate.
Sunfish said that the SS clutch pulley is 1 3/4 diameter, but it's actually smaller. Remember that the belts are running down in that V groove , so it's more likely to be closer to 1 1/2or even less. No offense to you sunfish, just pointing out that the V groove pulley diameters are misleading, like gear diameters vs. gear pitch diameters. SS advertises their flywheels run approximately 300 rpm. 1 1/2 clutch pulley (belt depth) x 18 1/4 flywheel x 3600 rpm = 295+ flywheel rpm. Can't estimate much closer than that. Paul has been building the SS for a long time, & knows his machines, and will openly discuss their operation. Classy Guy!
Dozer Man, here's the link to the pulley &rpm calculator I use.
Pulley and RPM Calculator | Engineering Information - Culver Armature and Motor
Hope this will help you SpeedPro guys figure out how fast your flywheels are running. The norm for these small engines is 3600 rpm at full throttle. Just plug in engine speed, your pulley & flywheel diameters & see how fast yours are turning.
Sorry I haven't been posting here for the past several days, but my computer died & is beyond repair. Trying to get an old one back in service now, but not having any luck getting micro soft Service Pack 3 onto it . Can't connect to the internet (wireless) without SP3, and can't get SP3 without being connected. What's a dummy like me to do? Any of you guys computer gurus? Right now I'm on a friend's computer, but hope to have something of my own running again soon. Will keep checking in on this & other threads as I can. Good luck guys. Claude