What is the Common Centerline?  Why is it Important?

Georgia State University says this about torque:   "Note that the torque is
maximum when the angle is 90 degrees. A practical way to calculate the magnitude of the torque is to first determine the lever arm and then multiply it times the applied force. The lever arm is the perpendicular distance from the axis of rotation to the line of action of the force."

Apply the same force to a different length lever arm and the torque output changes. The length of the lever arm includes the area on the head up to the center of the fastener. 

Common Centerline for interchangeable heads on industrial assembly tools

Common center line is measured from the center of the fastener to the top of the dove tail. 

Why Is Common Centerline Important?

Due to physical size constraints Sturtevant Richmont interchangeable heads have two common centerlines. Typically for sizes 32 mm  and below the common centerline is 36.5 mm. Sizes larger than 33 mm the common centerline extends to 98.4 mm.

If your application requires a preset wrench with a 60 mm open end head, it can be difficult to attach the head of the wrench to your tester. Our 3/4 ratchet and solid square drive have the same common centerline as our 60 mm open end. By switching to the 3/4 drive, calibration is now possible.

Our CCM micrometer adjustable wrenches are calibrated with either the 36.5 mm common centerline or the 98.4 mm common centerline. 

Be sure that the interchangeable heads you buy are accurate, reliable, and durable. 

Want More About Error Proofing?

Error Proofing From A Different Angle: Definition of error proofing and some observations by W. Edwards Deming.

Finding The Balance: In error proofing "one size fits no one."  To find what fits in your organization, start with the fundamental question of "How much responsibility for error proofing should be given to the tool and how much should be operator responsibility?" This section provides more on this concept.

Six Error Proofing Scenarios: Error proofing solutions all have trade offs. You can have control or you can have flexibility. Rarely do you get both. This page looks at error proofing extremes as well as the middle ground. 

How Much Are You Investing In Errors? If your current error proofing system or approach still leaves you with errors you are investing in errors, not error proofing. Error proofing is about quality and it is also very much about dollars and common sense. This pages digs into that.


Go To Interchangeable Heads.


Contact your Sturtevant Richmont Sales Professional.

Sturtevant Richmont tools are proudly made by highly capable union hands.