Two rules of thumb apply to hammermill screens in relation to applied
horsepower:
1. Never have less than 14 In² of screen area per horsepower
(more is always better).
2. Never have less than 4 In² of open area per horsepower.
Consider a typical 44” diameter by 30” wide hammermill grinding corn.
A tear circle machine will have approximately 3600 In² of raw screen
area. 3600 In² divided by 14 In²/HP = 250 HP maximum.