Technical information

Practical A.E.G Upgrade 2006

Why (and why not) is the one o’clock gear timing an issue?

It is widely believed that you need to set your sector gear with the tappet plate

post at the one o'clock position when reassembling your mechbox.

Although doing it this way doesn’t hurt, it does not have to be strictly "one

o'clocked". Think about it, the sector gear is a half-toothed gear which has

multiple teeth partially formed on the periphery and an idle area formed on the

remainder of the periphery. This design is supposed to provide an optimal means

for pulling the piston into a compressed position when needed. When idle, the

teeth formed on the periphery are not in touch with the piston. When you pull

the trigger, the sector gear is driven anti-clockwise, which eventually will have

its teeth getting in touch with the piston. This is when all the actions get started.

Effectively, this mean the gear system will time the gears properly by itself.

What we are trying to say is that as long as the sector gear is in a position where

all the teeth are facing downward (a position anywhere between 12:30 and 3:00,

such that no tooth is in touch with the piston at the time of installation), it will do

fine. Still, by having the gear “one o’clocked”, you can enjoy a slightly faster

initial response time (and peace of mind too). That’s all.