D

David Paule

Well Known Member
How do y'all cut the diagonal taper on the stiffeners?

I can think of several ways but I'd like to learn from your experiences. Even on an RV-3 there's lots of these things.

Thanks!

Dave
RV-3B
 
Marked them with a sharpe
Cut them on the bandsaw
Sanded to final size on the belt sander
Dressed them on de-burring wheel mounted in the drill press

Some guys score them and then just snap 'em off. I have never tried this as the method above worked quickly.
 
Tin Snips

Aviation Snips (Klein or Wiss) followed by the 6" deburring wheel in the drill press.
 
If you scribe the taper line with a utility knife and a straight edge 3 or 4 times, you can bend and snap the excess off easily and then just clean up the edge on your scotch brite wheel. I had some AL vise jaw protectors that I used as a straight edge. You could used two pieces of AL angle to do the same. Then just clamp the stiffener at the correct angle in your vise between the angles and scribe along the top of the angle that created the scribe line. I did all of the stiffeners for my 7A in about 30 minutes and all were perfectly straight.

I used this method whenever I needed to make straight cuts on AL sheet material. Way better, faster, straighter, and cleaner than any saw will ever do. A few passes with a utility knife creates a stress line and the AL will snap like glass after a few shallow bends. Try it!!!

Roberta:)
 
Sounds like a job for the $80 throatless shear from Harbor Fright. One pull of the handle (2 seconds). Chase them with the scotch-brite wheel if you've got a bunch. If doing one at a time, pull the file out of your back pocket and you'll have it smoothed by the time you walk back to your pile.
 
If you have a table saw you can cut them on that. I used a metal cutting blade in my table say for a lot of things. I remember reading "back in the day" that some folks even used a hollow ground planer blade just for this very thing. YOu have to make a fixture out of wood to hold them at the correct angle for the rip cut you will be doing. File and/or belt sander to finish the edges afterwards...

Richard
RV-4 N144KT
 
Snips

Snips all the way - VERY simple, VERY fast and accurate. I started out using my band saw and that worked quite well, but the snips were faster and easier. Finish up on a 6" Scotchbrite wheel. Be sure to use right or left hand snips as appropriate.
 
Snips, sander, file, done.

Thanks everyone for the suggestions.

Finished the ones for the rudder as described above.

Tried other things with no luck but a lot of fun -

Took a couple trials of the scoring technique, which I couldn't get to work for me. Apparently I'm missing something.

Went to the store and tried a paper cutter, sigh, they don't make them like they used to.

An old technique involving a chisel and a vice didn't work because the "good" part was the cut-off. It would take more tooling to get the stiffener to be airworthy this way.

I nearly made my own little shear. Didn't when I realized that snips would do the job in a flash. Turns out that it isn't so hard to do, though: a bit of wood, three scraps of 4130 (anvil, clamp and blade), a single bolt would do it plus a vice. Easier to merely use tools on hand.

I didn't use the band saw. Mine is somewhat aggressive (3/4 hp, 6.5 tpi blade) and using it for these cuts would take more effort to keep it good than snips would.

Thanks again!

Dave
 
having just accomplished this, I can say without hesitation that a DiAcro 6" corner notcher is the bee's knees for cutting the taper and squaring up the ends. I picked one up a while back on Craigslist. Very clean and precise, and super fast.
 
Ironflight said:
Repucci's method - exactly!
Click to expand...

I haven't gotten that far yet with the "real" airplane. But, I was working on the airfoil practice kit from Van's which uses the same sort of tapered stiffners.

I don't have a band saw yet. So, I tried cutting with Wiss snips, per instructions. They distorted the aluminum to the point that I was worried about work-hardening the extrusion. After a little thinking, I realized I had the perfect tool for this in my old Taco Wagon. I scribed the taper line as above and used a hand nibbler to cut, then finished the edges again, as above. I think they're <$30 from one of the tool suppliers.
 
Last edited:
You must log in or register to reply here.