Improved Aluminum Knife Plans

Even though the Olfa scoring knife gets the job done when cutting aluminum sheet, I kept thinking there must be a much better way to cleanly cut out aluminum sheet. Knife blades are designed to cut soft and flexible materials. When we use an Olfa or utility knife blade to cut T6 tempered aluminum, the aluminum resists spreading at the cut line and requires many repeated scores. Even though the aluminum is thin, the blade must cold flow the material before it is scored enough to snap. Also, the hardened aluminum dulls the steel blade quickly.

In industry, if hardened aluminum cannot be sheared, a cutter or saw tooth removes aluminum chips to cut through. I have designed an improved aluminum knife that uses a long lasting carbide “thin bit” lathe insert to cut sheet aluminum much faster.

A carbide cutter is mounted in the handle of an 8” crescent wrench with a little modification. This uses a carbide “Thin bit” cutter insert in a handle to make a better aluminum knife. The carbide lathe bit cutting edge is only .019” thick and this makes a clean cut chip of .005 - ,010” thick per stroke – much faster than the Olfa knife. The carbide cuts aluminum like butter and the insert should stay sharp for an entire aluminum airplane!

If the first cutting edge gets dull or chipped, remove the screw and rotate the other cutter into position. Because carbide is brittle, be careful not to twist or side load the cutter. To make a cushioned grip, cut a 4 ½ “ long piece of ¾” ID rubber hose and slip on to the handle. The tool costs $ 28 – 37 to make and it saves a lot of time building your plane.

Alum_Knife_PLANS.doc 

Best Regards and Happy Building,

Larry Zepp,