An adjustable back-stop for dropping-on operation may be fitted on each fence plate. Although the two stop gauges look very close they are neither identical nor reversible. However only one element out of three is specific. The support bars and back-stops are identical whereas the adjustable block is related to a side and its back-face is inverted as a mirror would do.

Two wing-nuts clamp the support bar that slides along the groove in the rear of the fence plate. Dimensions and axis result from other components.

A metal bar holds the wooden stop block and enables adjustments up to 350 millimetres. The axis between holes of the support bar are directly related to that dimension.

The dado slides along the support bar and the screwed pin aims the 6 mm holes of the bar. A thin aluminium strip screwed at the bottom prevent the adjustable block from going away when the wing-nut is screwed on the embedded threaded rod.

The front-side mechanism allows the stop block to slide along its dado. A thin screwed aluminium plate keeps the bar into the dado and a bolt made up of a threaded rod and a nut and a wing-nut locks the back-stop.