Mul-T-Lock Mushroom Driver Pins - 5 Pack

These rare mushroom driver pins have been out of production for decades and present a very unique picking challenge.

Picking Experience

I've found that they produce the same false set depth that normal spooled drivers do, but like Medeco mushrooms they get harder and harder to lift as they travel until they seem to hit a wall and won't set or make a nice click. When the false set is shallow, some good old fashioned brute force will get them a touch higher and allow them to set with a satisfying click, but if the false set is deep they need counter rotation and seem to set more smoothly (less other pins falling) than spools.

History

I've found that that unlike the older styles of standard and spooled driver pins, every mushroom driver features the modern spooled inner pin. In addition, every mushroom driver is a 'full size' pin as opposed to modern drivers which are all the slightly shorter 'cam size' pins now used in both mortise and cam locks. To me, this implies mushroom pins were produced in a small quantity right before Mul-T-Lock started production of modern standard and spooled driver pins.

If my theory is right, the overall lineage of Mul-T-Lock pins from oldest to newest would be:

Era 1: Standard (full and cam size), spooled (full size), serrated (full and cam size). All with no inner spooling. Spooled pins do not have equal thickness lips.

Era 2: Mushroom (full size) with inner spooling.

Era 3: Standard (cam size), spooled (cam size). All with inner spooling. Spooled pins have equal thickness lips.

Observations

Most of the locks I have found mushroom driver pins in only included 1-2 countermilled key pins for them to interact with. The same locks are where I found my very few examples of the rare countermilled size D, and extremely rare countermilled size C key pins. Only sizes A and B are made today.