| Place the non-slip instrument on test surface, with all shims in the lowered position. Make the first cut drawing the blade downward with light pressure against the shim in a manner similar to making a straight line with a straight edge. Without moving position of instrument on the test surface rotate the first shim upward and out of the way of the second shim so that second cut can be made using second shim as a guide.
Repeat this process until all shims have been rotated upward. Since there are ten shims there will be eleven uniform cuts. Next, rotate the instrument 90° on the test surface and repeat the above procedure to place the same number of uniform cuts intersecting those first produced. Proceed with test outlined in ASTM D3359.
The Fig. 2 sketch depicts the instrument with the 1.5mm shims in use. Five shims have been rotated upward with five cuts having been made and the assembly is ready for the sixth cut. Opposite end of instrument is fitted with ten 1.0mm shims.
The procedure for making 3mm spaced cuts is identical to the above except two of the shims are rotated upward following each cut. Six equally spaced cuts are produced when operating in this mode. Cuts spaced at 2mm are produced by using the 1mm shims, rotated two at a time for each cut. You can have all of the following mm spacings and still have three cuts in each direction in the cross cut pattern: 1, 1.5, 2, 3, 4, 4.5, 5 and 6. According to discussions heard in the ASTM, the larger spacings are required in some “bridge” and industrial work. |
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