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Olfa Knife
No Shear? No Sweat!
The Olfa P-800 does a nice job of cutting aluminum. This handy knife allows you to do a fine cut without the use of a shear. I read about P-800 in the Bearhawk mail-list and decided to try it. You line up a straight edge along the line you want to cut and pull the knife along it to score your cutting surface 3 to 6 times. The number of times will depend on your thickness of material as well as on how hard you are pressing down on the knife. Once you have scored the sheet, line up the score line on the edge of your table and bend along the line. Bend to 90° and back and you will end up with a straight and relatively clean cut. This “clean-ness” of the cut depends on the thickness of the material you are cutting. After I cut .016 material I just have to run the deburring tool along the edge. If I have cut .063 material, I have a little filing to do before I deburr.
I have made cuts 12 feet long on thin (.025) material but you will have to experiment. For thicker material, the cuts have to be much shorter (my max. is about 12 inches of the .063) and you should clamp the cut line between some wooden blocks in your vice. It sounds crude but it was much cleaner, with less material waste than cutting the parts in the bandsaw.
When doing flap ribs for my 601 XL project I cut the first rib blank with snips and finished the edges. Then I used that rib blank as the straight edge to score out all my other rib blanks. It worked like a charm and you can make one cut be the edge for two parts.
This works great for cutting a shape out of the interior of a sheet part as well. I had to make a wide slot (60 mm) with rounded ends in one piece of sheet. First I marked it out, then drilled pilot holes before using the fly cutter to make 60 mm diameter holes at both ends of the slot. Then I used a straight edge to score a line tangent to both holes on each side of the slot. At that point I couldn’t make the bends to snap out the parts so I used the tin snips to rough cut a line down the center of the slot. Then I could break out the excess material on either side of the slot. Of course the point where the knife cut meets the tangent of the circles isn’t very clean but for this slot I only had 4 small spots that required a few seconds of filing.
You often pull the knife right off the edge of the sheet you are cutting. This can cause damage to the surface you are cutting on so stay off the dining room table. I slip a small piece of arborite off an old kitchen counter under my cutting area.
I believe this will work for slightly curved cuts as well. I will be trying it for my main wing ribs after I have the first blank cut, trimmed and deburred.
You can buy the P-800 in the tool section at Home Depot. To see a picture go the website below. Happy cutting.