Delta P-20 belt drive, Greenfield_Bob

[Mick Walker]

Bob you mentioned that you can't find the right speed on your P-20. I have never tried this but read about it on a different forum. Place the belt on the slowest pulley for the saw and on the next pulley over for the motor. That way you have at least 12 speeds or more with your P-20. Mick.

[Sparkplug]

36 speeds are possible on a P-20 saw. That is about 35 more speeds than any experienced scroller needs. The belt is stretchy tough round neoprene and the edges of the pulleys are nicely rounded off. Some that have never seen a P-20 and just talk from hear-say are either misinformed or are not aware of the facts. They think of it as conventional V pulleys and V belts and it is nothing like that.

Delta P-20 Scrollsaw Speeds

Assume the motor turns at 1725 RPM
Position 1 refers to far left belt position when facing the saw.

STANDARD SPEEDS
Belt Position 1 2 3 4 5 6
Motor Pulley Dia. (in) 2.648 2.450 2.207 2.013 1.379 0.869
Driven Pulley Dia. (in) 2.284 2.486 2.719 2.894 3.400 3.748
Speed 2000 1700 1400 1200 700 400


ADDITIONAL SPEEDS
Driven Pulley Position
Motor Pulley Position 1 2 3 4 5 6
1 2000 1837 1680 1578 1343 1219
2 1850 1700 1554 1460 1243 1128
3 1667 1531 1400 1316 1120 1016
4 1520 1397 1277 1200 1021 926
5 1041 957 875 822 700 635
6 656 603 551 518 441 400



But for any experienced scrollers variable speed is a non issue because they generally find one speed that suits them best out of all the ones available and never change it from one year to the next regardless of the simplicity or complexity of the piece being sawed. If it is desired to occasionaly change the speed from their favorite one of choice it takes less than ten seconds to do so.
Variable speed is viewed by many as just a selling point and it can cause major repair expenses when it fails and often does. VS also robs the motor of power.
Direct drive belt/pulley systems give full power at all times at all speeds.
Sparky.

[3_M]

Hi Sparky,

I have to agree with you about speed. I have a variable speed saw and keep it almost always on high. When the pattern is intricate, I just push the wood slower into the blade.

Mike M