Trailing Edge Profile Sander

Trailing Edge Profile Sander · roddie Tue Apr 21, 2015 9:28 am

Thought I'd post this tip here, after achieving satisfactory results in my "Rodd-O-Gyro" thread.

I was faced with contouring a radius-taper into the trailing-edge of my elevator. Various sanding jigs are something that we could all benefit from.. but they are often difficult or time-consuming to build. Here's something that I found in the kitchen drawer.. A "Smith's" knife sharpener. It will handle up to approx. 3/16" (4.5mm) thickness sheet.

Trailing Edge Profile Sander 4-21-113

If you think this is silly.. try it on a piece of scrap. I used the "fine" (round ceramic rods) side to achieve my results. The carbide-blades also work.. but are more for initial "roughing-out" and should be used with very light pressure. I wouldn't recommend the carbide blades on soft stock. Sighting the gap between the wood and where the rods intersect, lets you know how sharp the taper is. Actually.. building any type of a "V" sanding fixture for forming tapers is well worth the effort.

Re: Trailing Edge Profile Sander · GallopingGhostler Tue Apr 21, 2015 10:12 am

That's a way to do it, Roddie. For myself, after installing rectangular profile trailing edge, I take a ball pen and a rule, put a line down the middle of the back edge. Then use an auto body block sander with varying grits, coarse first for fast cutting, using the line as a guide for making the wedge profile. Then do the other side. Use medium grit for further honing down to final profile. Then fine to remove roughness and polish wood for covering.

It is crude, but works for me. It also works for leading edges, too.

Re: Trailing Edge Profile Sander · getback Tue Apr 21, 2015 10:38 am

Greenie for you Man I just tried it on some 1/16 " and worked well mine are carbon steel , not worth a crap for a GOOD long lasting edge on a knife but , this is great ! a little light sanding to get the feathering off and your good ... I think we should have a Thread just for TIPS and Tricks in Building ?????? Easter Bunny

Re: Trailing Edge Profile Sander · roddie Tue Apr 21, 2015 11:16 am

Very cool Eric! The angle (45 degrees ?) of the cutters in the knife-sharpener is ideal for not thinning the edge out too much.. and it removes stock from both sides at once. There is still some light sanding needed to blend.. but it goes very quickly.

Don't have a knife-sharpener? Here's an alternative that allows you set your own taper-angle.

Trailing Edge Profile Sander Dsc02619

Draw the wood through the blades in one direction toward you. Swap ends; to taper the other side.. then feather-sand using a block. Once the wood bottoms-out in the "V".. you can feel it drawing smoother through the blades, and an even edge/taper was surprisingly easy to achieve. The piece of wood shown with the scissors, was a scrap pc. of hard-grade balsa and had a knot on its edge. I was still able to cut a rough-taper quickly.

Re: Trailing Edge Profile Sander · pkrankow Tue Apr 21, 2015 12:10 pm

I went and got said sharpener since I was at lowes ($4) and I had another excuse to get one. The concept is great. The ceramics burnished the edge, but did not actually remove material...

The carbide made quick work of some hard balsa, 1/8 inch. I was having difficulty keeping it centered, but the drift was reasonable. A pen line would probably fix the centering issue.

I like the scissors idea better.

For speed, neatness, and evenness this blows template guides out of the water!

Phil

Re: Trailing Edge Profile Sander · **RknRusty** Tue Apr 21, 2015 2:58 pm

I have one of those ceramic sharpeners, and also a great Planes(I think) contour sander with the hinge line angle and several airfoils. I have yet to use it... but after today's flying session, I'll be needing it lol. Poor Ukey took another lick, an inverted skid during the inverted half of the reverse wingover. First flight of the day.

I like the Skizzers in the vice, Roddie, you get another greenie for that. You're the master of improvisation.

I'll file my flight report later.
Rusty

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