Pivot pins are small metal pins found on the bottom of sashes in tilt-in single or double hung windows.
They are used to connect the sash to the balancing system by fitting in the cam of the shoe. When the window is tilted out, the pivot pin turns the cam and locks the shoe in place so the balancer does not pull it up while the weight of the sash is removed.
This page will inform you on the types of pivot pins, what can go wrong with them and how to identify a broken pivot pin.
Signs of a broken pivot pin
The sash falls at one side of the window
The sash is difficult to open
The sash will not stay up
Pin is visibly cracked
Why do pivot pins break?
Typically, pivot pins break from age, excessive force and low-quality materials.
Malfunctioning balancers require more force to operate the sash and all of that force is exerted on the pivot pin.
Many pivot pins are made from composite "pot metal" (a metal alloy with a low melting point) that cracks easily. Quality pivot pins are made from stainless steel.
Types of Pivot Pins
like shoes, pivot pins are incredibly varied and each window needs the particular pin designed for it. Your window tech can identify and record the model of pin required and order any non-stock pivot pins.
Some pivot pins are symmetrical, others have specific shapes to fit certain shoes. Depending on the type of pin, they can be universal, or left and right specific.
Knife Latch Pivot Pin
Knife-latch pivot pins are used for knife latch balancers. A knife-latch system digs into the window's side channel to lock the shoe when the tilt-in sash is removed. The pin triggers the knife-latch to lock when removed and releases when placed in the shoe. Knife-latch pivot pins are left and right specific.
Side mounting pivot pins screw to the side of the sash. They can be found in a range of windows. This set is designed for use with a knife latch balancer, but not all side mounting pivot pins are for knife latches or left and right specific.
Bottom mounting pivot pins screw to the bottom of the window and can either be inserted into an exposed channel channel or a closed channel in the sash. On the left is a standard 'U-shape' steel pivot pin inserted into a locking cam shoe. On the right is a pivot pin for a shoe used in a constant force balancing system. Many bottom mounting pins are universal, but some are left and right specific.
Set-in pivot pins are built into the sash. These can often be found in kit windows designed for use with a jamb-liner.