This Fuhr gearbox features a keywind mechanism. Be sure to remove the yellow plastic travel protector before fitting. 

Fuhr multipoint door lock gearboxes feature a deadbolt that throws 20mm, except on 25mm and 30mm backset locks, where it throws 14mm. The gearbox measures 220mm x width + 18mm. The latch and deadbolt are both 31mm high and there is 61mm between the bottom of the latch and the top of the deadbolt. Gearboxes are fixed to faceplates with 3 screws. The distance from the top screw to the middle screw is 91mm and the distance from the middle to the bottom screw is 108mm.

Fuhr locks feature a ball bearing and spring pre-fitted. There is a tiny notch on the sliding internal strip that the ball bearing engages (under spring tension) and give a more positive locking feel when handle operated. If you try a lock without this spring and ball bearing fitted, you'll notice the difference. Some replacement gearboxes on the market are sold without the ball bearing and spring, but all of Duffells' replacement Fuhr gearboxes come with these pre-fitted for a direct swap.

When replacing an existing Fuhr multipoint lock or gearbox, you may find that the latch differs. This can cause problems when the latch locates in the keep. Old versions of Fuhr multipoint lock gearboxes had a latch that was 28mm high, whereas newer versions are 33mm high. If the latch on the old lock is not damaged, it is possible to remove it by undoing the allen key bolt in the old gearbox, removing it and re-using it in the new lock.

We stock a range of associated products for Fuhr 855 - Key Wind gearboxes, including multipoint door locks, keeps, spindles, handles and accessories.

To lock the door

1. On closing the door, the latch is automatically engaged.

2. Turn the key to throw and engage or "wind" out the locking points.

To unlock the door

1. Turn the key to unlock the door by "unwinding" the locking points.

2. A further quarter turn of the key will retract the latch.

Operation: Key wind

Latch reversal: Undo the screw in the side of the lock case adjacent to the latch. Remove the latch, reverse, reinsert and replace the screw.