With regard to accuracy of work in the shop, where it depends on yourself and the system you observe, I cannot do better than write out for you here the written notice by which the matter is regulated in my own practice with regard to cartoons.
"Rules to be Observed in Setting out Forms for Cartoons.
"In every case of setting out any form, or batch of forms, for new windows the truth of the first long line ruled must be tested by stretching a thread.
If the lath is proved to be out, it must at once be sent to a joiner to be accurately 'shot,' and the accuracy of both its edges must then be tested with a thread.
The first right angle made (for the corner of the form) must also be tested by raising a perpendicular, with a radius of the compasses not less than 6 inches and with a needle-pointed pencil, and by the subjoined formula and no other.
From a given point in a given straight line to raise a perpendicular. Let A B be the given straight line (this must be the long side of the form, and the point B must be one corner of the base-line): it is required to raise from the point B a line perpendicular to the line A B.
Fig. 71.
(1) Prolong the line A B at least 6 inches beyond B (if there is not room on the paper, it must be pinned on to a smooth board, and a piece of paper pinned on, so as to meet the edge of it, and continue it to the required distance).