What is a Norris-style adjuster?
Most metal bench planes have Stanley / Bailey-style iron depth adjusters and separate lateral adjusters, to keep the cutting edge parallel across the sole. If the cutting edge is not parallel, any cut made by the plane will be on a slight slant.
However, some planes have a single “Norris-style” adjuster for changing both the iron’s depth and its lateral angle.
The Norris adjuster was invented and patented by UK tool manufacturer T. Norris & Son in 1913.
There were a few modifications to the original before it became the exact mechanism that is used today.
With the Norris-style adjuster, both lateral and vertical movements of the iron are controlled by a single shaft.
Lateral adjustment is achieved by moving the thumbwheel of the adjuster from side to side.
Iron depth adjustment works by turning the thumbwheel clockwise to advance and anti-clockwise to retract the iron. A pin, or very short dowel, on the adjuster fits into a hole in the iron and pushes or pulls the iron as the thumbwheel is turned, or skews the iron from side to side when the thumbwheel is moved to the left or right.
Some experts say the Norris adjuster is not quite as effective as the Stanley / Bailey type because it is more prone to "backlash" after the mechanism has been in use for a while.
Backlash is the term given to the amount of free play in the iron depth adjustment mechanism.
'Free play' can cause the blade can move upwards on its own after it has been adjusted to the desired position.
Seefor more information about this common problem and how you can avoid it.