Blade anatomies
#1
One of the most used tools in model railroading is the hobby knife. Probably the most popular is the Exacto knife. While it may be the most popular, it may not be the best blade to use for your application. It all depends on WHAT you are cutting, and the TYPE of cuts you are making. Curved cuts of any kind, as well as cutting in tight places, are done well with the pointed end of an Exacto. An Exacto also has unlimited other uses.

If you are making repetitive straight cuts in wood or styrene up to 1/8" thick, then a SERB (Single Edge Razor Blade) is best. The reason for this is the "included blade angle". Careful measurements and some basic trigonometry produced the data for the following sketches, which show the angles for 4 popular blades.

[Image: AhMH9i7.jpg]

[Image: IdlwQfd.jpg]

[Image: bSknNwF.jpg]

[Image: 8QAusyu.jpg]


Clearly the SERB is thinner, and has a much more acute blade angle than the others.

If you cut (or score and then snap) styrene or similar materials with an exacto blade, box cutter, or utility knife, you may wind up with a ridge on the cut edge. Using a single edge razor blade eliminates this ridge, due to the thinner blade, and a more acute angle to the cutting surface. AN ADDED BONUS IS THAT IT WILL HOLD ITS EDGE LONGER THAN AN EXACTO BLADE. Also, no ridge means that sanding can be almost eliminated.
Blades are cheaper too (100 for about $6.00).

This thread is NOT to convince anyone to use a different blade. Look at the sketches and then decide for yourself. More importantly, use what you are comfortable with.

I made a cheap SERB holder and I have sketches and pics so you can make your own.
Gary
Charter member of CAMRRA.
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