A very compact instrument for making 1.0, 1.5, 2.0, 3.0, 4.0, 4.5, 5.0 and 6.0mm spaced crosscuts on both smooth and flat surfaces as well as somewhat rough coated surfaces. Suggested for adhesion tests on bridges, ships, etc.

Fig. 1 depicts Dual Shim Assembly with one shoulder bolt removed from right hand set of shims; and knife making a cut in the test surface.

Note progressive positions of shims after each cut has been made. Also note that length of cutter knife blade may be adjusted to any length to facilitate position of cutting procedure.

Multiple cuts in a test specimen must be evenly spaced if results are to be meaningful and repeatable. To insure even spacing of the cuts, a specially designed, versatile instrument with Blade Guides or Metal Shims is furnished as a part of this kit. The Dual Metal Shim Assembly provides spacing of 1.0, 1.5, 2.0, 3.0, 4.0, 4.5, 5.0, and 6.0mm. Dimensions of the assembly are 1cm thick, 6 cm wide and 8.5 cm long.

The cutter knife blade is made from the finest steel. When not being used, it retracts into a plastic housing for protection. There are scores in the blade which permits the end to be snapped away so that up to thirteen fresh sharp tips may be exposed. The entire blade is readily replaceable in the handle.

Prepare the test specimen and select the area for test as outlined in ASTM D 3359. Inspect the tip of the cutter knife and, if dull from prior use, remove top plastic cap and with only one segment of the cutter extending from the protective plastic housing, place cap over end of the blade and snap off the end segment.

Select the thickness of the cuts to be used and remove the lower shoulder bolt from the metal shims of the Dual Shim Assembly which are of this thickness.

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 D 3359.

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.