Fig. 623.
[Fig. 623] represents another form of parallel edged shears in which the fit of the carriage to the shears is effected at the front end only, the other or back edge being clear of contact with the carriage, but provided with a gib to prevent the carriage from lifting. This allows for any difference in expansion and contraction between the carriage and the shears, while maintaining the fit of the carriage to the bed.
Fig. 624.
A modification of this form (both these forms being taken from “Mechanics”) is shown in [Fig. 624], in which the underneath side of the front edge is beveled so that but one row of screws is required to effect the adjustment.
Fig. 625.