5. Apparatus
5.1 A set of calibrated drawing leads (preferred) or equivalent
calibrated wood pencils meeting the following scale of
hardness:
6B25B24B23B22B2B2HB2F2H22H23H24H25H26H
Softer Harder
(1)
The difference between two adjacent leads shall be considered
one unit of hardness.
5.2 Mechanical Lead Holder, for drawing leads if used.
5.3 Mechanical Sharpener, draftsman-type, is helpful for
trimming wood pencils if used.
5.4 Abrasive Paper, grit No. 400.