Grasp handle and rotate it upward with respect to the line of contact of the guide with the test surface.Place the cutter assembly on the test specimen so that the guide and cutter rests on the substrate.Position the blade in the handle with the holes facing the securing set screws, take care not to over tighten.Prepare test specimen as outlined in ASTM D3359.For coatings having a thickness greater than 5 mils (125 µm) space the cuts 5.0 mm apart and make 5 cuts (12633) unless otherwise agreed upon. For coatings having a dry film thickness between 2.0 mils (50 µm) and 5 mils (125 µm), space the cuts 2 mm apart and make six cuts (12610) unless otherwise agreed upon. The tolerance on tip length is greatly improved permitting lower pressure to be used on the cutter and avoiding gouging of the supporting base with a long tipĪs general guide for coatings having a dry film thickness up to and including 2.0 mils (50 µm) space the cuts 1 mm apart and make eleven cuts (12603) unless otherwise agreed upon. There is a cleaner edge cut where the coating interfaces with the supporting base.The teeth are stronger and less subject to damage.This is then followed by a fine lateral honing which slightly modifies the teeth. The cutters are first produced to insure a normal cut.
An additional last step in the production process provides essentially zero tolerance on blade length. Even this very small variation is just not good enough for best results from the test. Even with the best possible production tools and procedures, it is very difficult to hold the tolerance on individual tooth length closer than ☐.0005 inches. A further very important improvement to the multiple tip cutter is not immediately apparent. The holes must face the securing set screws. This prevents the cutter from being improperly secured in the handle.
Handle mounting holes do not go all the way through the cutter. Not only are they produced to very close tolerances, but also as a final step in production they are given a black oxide coating (bluing) to prevent rusting. This spacing provides segment areas ranging from 0.21 square mm to 6.66 square mm.Ĭross Hatch Blades - The multiple tip cutters for the Paint Adhesion Test Kit are specially designed to provide optimum results. The variable spaced multiple tooth cutter has 14 teeth providing 13 spaces between the teeth ranging from 0.46 mm to 2.58 mm.
The following table shows the segment area in square mm for each of the segments in the variable spaced multi-tooth crosshatch pattern.
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