Compute Tonnage

How to compute tonnage requirements:

1. General - When pressure per square inch is known:
   psi x area of work/2000 = 2 tons of ram force required
   Example: Where it is known that 100 psi is needed to do a job on a 5" x 8" wide piece.
   100 x 5" x 8"/2000 = 2 tons
2. Press Fit - To determine the force required to press fit two round pieces together such as a shaft pressed into a bushing, use the following formula:
   F = D x ϖ x L x I x P/2
   Where:

F = force required in tons
D = diameter of the part to be pressed in inches
L = length of part to be pressed in inches (Note: the length of the interference fit only.)
I = interference in inches (usually .002" to .006")
P = pressure factor (See table below).

Diameter (inches)	Pressure Factor	Diameter (inches)	Pressure Factor	Diameter (inches)	Pressure Factor	Diameter (inches)	Pressure Factor
1	500	3	156	5	91	7	64
1¼	395	3¼	143	5¼	86	7¼	61
1½	325	3½	132	5½	82	7½	59
1¾	276	3¾	123	5¾	78	7¾	57
2	240	4	115	6	75	8	55
2¼	212	4¼	108	6¼	72
2½	189	4½	101	6½	69
2¾	171	4¾	96	6¾	66

Example: A steel shaft 2" in diameter pressed into a hole 3" long. The interference fit between the two diameters is .006".
2" x 3.14 x 3" x .006" x (240/2) = 13.56 tons