Used for working with 45° elbows to eliminate figuring and chance of error
Graduated one side, in black, inches to 1/16ths both edges
Other side in red, 45° scale inches to 1/16ths upper edge only
Turning rule from black to red gives the corresponding 45° elbow measurement
Example: Sketch at right shows 10” 45° offset; by turning rule at 10” graduation on standard inch side red graduation directly opposite indicates center-to-center fittings to be 14 1/8” Actual pipe length varies as allowances must be made for type of pipe and fitting used. All other size offsets are calculated in same manner. Where offset is longer than length of rule, add 45° scale measurement of extra distance to last scale on rule (101-13/16).
