For a shutter (or anything else that uses a hinge to open) to work properly, it needs to be counterbalanced in order to swing properly. The strap and pintle offsets don’t have to be the same dimension. A common combination is a 1½” pintle and a ½” strap.
The larger the hinge offset, the larger the swing is and the further the shutter will protrude away from the hinge pivot point. This distance is also called the “throw.”
Before installing a new shutter, it’s important to understand the amount of throw you’ll need in order to install the correct hinge.
To properly measure a pintle and strap offset, you start from the base and measure to the center of the pintle. There are two options when measuring a pintle offset: including the plate and not including the plate. Luckily, your measurement will be close enough regardless of which you choose.
You’ll then measure the strap part of the offset. This measurement is similar to the pintle. You measure the knuckle to the center, measure the hinge joint and subtract the thickness of the strap.
For this measurement, it’s also important to remember to measure the strap perpendicular to where it’s mounted on the shutter face.
Offset Measurement Visuals
Flat Straps with Offset Pintle
Hinge Offset and Throw Combinations