JP Timing Sprockets and Gears are made from Billet Steel for all Performance
JP Timing Sprockets and Gears are machined on CNC lathes.
Billet steel blanks are cut from six metre lengths of steel which are then
machined using CNC lathes to form the required part. These are carried out
in two operations; the first operation involves boring the hole (so it will
fit on the crankshaft or camshaft) and the chain groove; the second operation
finishes the part off after it has been turned around in the lathe.
Hobbing cuts the sprocket teeth.
The parts from the lathes must have the teeth or gears cut in them. This
process is called hobbing for sprockets and straight cut gears or gear cutting
(generation) for helical gears. This process is the longest in the manufacture
of sprockets and gears as it cannot be rushed.
After the sprockets have been hobbed they will be linished to remove any
burrs. For gears they are shaved, this process involves a small amount of
material being removed if necessary to ensure that the gears mesh at exactly
90 degrees to each other. If this angle is out by even a second it will
wear the gears prematurely or break.
The final manufacturing process for crank sprockets and gears is to induction
harden the teeth. This process involves using electricity to heat the outside
of the sprocket or gear to 1000 degrees Celsius and then quench it instantly
in water. Induction hardening is used to pre-work harden the sprockets and
gears so they will not wear as rapidly as un hardened sprockets. This means
that the sprocket will last longer and save on chain wear. For more information
on hardening follow this link.