Choices in Knife Blades

For cutting any thin masking material on a flat surface, be it a painted latex material, a commercial frisket film, or even masking tape, you will eventually be unable to avoid the need to cut curves for your designs. While any fresh, sharp blade can do the job, the angle of attack for that blade comes into play. Too sharp an angle, and you can't get it to cut without ripping the mask or skipping along it. Too shallow an angle, and controlling the blade handle gets to be a challenge -- especially within the confines of an R/C body shell.

001

Notice the angle presented by each of these blades - an X-Acto #16 on the left, an X-Acto #11 on the right. Pointed straight up, the #11 is pretty much unusable at that angle. The #16 on the other hand could concievably cut a thin, compliant mask.

002

To match the angle of the #16, the #11 has to be tilted. Look at the lateral distance from the tip of the blade to the end. On the #16, while it's about 5/16 of an inch, for all functional purposes it's actually zero, as the blade is vertical an can pivot on its tip. On the #11, it's 3/4 of an inch. Extrapolate the length of the handle from the blade as shown, and you can imagine just how much of an arc the handle will traverse using a #11 to match the turning capability of the #16, which again can pivot on its own tip.

003

If you want to make smooth flowing curves, like those in a traditional hotrod flame pattern, you'll have to get the angle of the blade to be as shallow as possible. Notice how both blades are about matched in angle, and yet the lateral tip-to-end distance is 3/4 of an inch for the #16, and 1-1/4 inches (plural!) for the #11. Again, extrapolating the handle onto each blade, and the #11 will require much more swing room than the #16 to create the same curved cut.

Just an illustration of how slight variations on the same tool can make a significant difference in the finished product.

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Content Copyright © 2005 Kevin Maynes