15
Setting up the Machine (Continued)
General Notes
The morticer will generate a lot of ‘grip’ on the chisel, especially the first cut, or if the timber is a
little green. Make sure you use the hold down yoke to help control the timber during the raise
operation of the morticer.
A lot of setting and resetting is required for the various components of the morticer. A lot of the
settings are more easily achieved by measurement from the front edge of the table, and a broad
assumption is made that the front edge of the table is parallel to the face of the backfence. The
table is indeed rectangular, but the edges are not highly precision machined faces, within a 5
decimal place tolerance. If you ascertain that the front edge is NOT, in fact, parallel with the face
of the backfence, putting a permanent mark on each side of the table from where you will carry
out your measurements, will ensure that the discrepancies will be constant and can be added or
subtracted from the initial measurement you establish.
Setting the chisel Square
When the chisel is tightened in the machine it must normally be square to the backfence.
The easiest way to achieve this is to bring the headbox down to bring the chisel as close to the
table as possible, make sure the backfence is locked in place, set a square against the
backfence and set the side of the chisel against the square. and clamp tight. (Remember to have
the chipejection slot in the chisel to the side from which you will cut the mortice).
Setting up the backfence
Usually the easiest method is mark out the mortice, place the workpiece on the table, lined up
under the chisel and then move the backfence to the workpiece and lock it in position. Another
way is by measurement, provided you know where the mortice is to be in the workpiece, the
backfence can be set away from the chisel by measurement, either directly off the backfence or
as a complement figure from the front of the table. A useful accessory for this operation is an
engineers combination square (where the graduated top blade is moveable).
Tip. Because of the necessity of constantly setting and resetting the backfence, it could be very
useful to scribe a series of parallel lines (about 3mm apart?) on the table to aid the setting
operation.
Quick Setting the Backfence/Chisel/Mortice Position
A quick set method for achieving the correct position of the backfence is as follows:-
1.
Mark the centre line of the mortice.
2.
Lower the headbox so that the auger point just pierces the centre mark, but not so hard that
the workpiece cannot be ‘spun’. Hold the headbox in place.
Note English pattern augers without the centre point can be used by driving the cutting spurs into
the timber. Have care with the smallest chisel sizes and only drive in sufficiently hard for the
auger to lock into the workpiece.
3.
Turn the workpiece about the point of the auger until it is approximately parallel with the front
edge of the table, measure from your permanent marks and ‘true up’.
4.
Clamp the workpiece in position.
5.
Lay the backfence up to the workpiece and clamp that in position.
