What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Coutersinking the trailing edge wedge

AndyWAUS

Member
I'm building the empennage, and so far my experience has been quite frustrating. :) Today was the first time I felt like things were going my way. So I want to share a little success story.

When building the rudder, I used a hand drill to countersink the trailing edge wedge. I follow videos by Jason Ellis on youtube, and he used the hand drill. My rudder TE wedge came out looking like ****. Half the holes were elongated, countersunk to a different depth, rough edge etc. Especially the two holes at the ends of the TE wedge. (I'm sure Jason's countersunk holes were better, I just apparently can't hold the drill steady).

When building the elevators, I was dreading to work with the wedge. So I decided to do something different. Instead of using the hand drill, I put the countersink cage in the drill press. I glued another unused piece of the wedge from the training project to the drill press's worktable. This is so I could have the csink cage contact the wedge at exactly the right angle. So basically I put my wedge on top of another wedge oriented the opposite way to make a rectangle out of two triangles. I had the csink cage fixed to the drill press with a piece of safety wire so the cage itself doesn't rotate.

This way, my countersink holes came out PERFECT. It felt very satisfying to prep it so neatly. Even the two outermost ones came perfectly round. Oh, I also set the drill press to the lowest possible speed. With the hand drill I was using 90 psi, which gives like 4000 rpm. Turns out, for countersinking it is absolutely unnecessary to blast it this fast, and slower speed gives a better result.

It may seem to you experienced guys like I'm stating incredibly obvious things. But I saw a couple folks who here who are newbies just like me, so maybe it'll help someone.

Andy
 
Countersink

I'm building the empennage, and so far my experience has been quite frustrating. :) Today was the first time I felt like things were going my way. So I want to share a little success story.

When building the rudder, I used a hand drill to countersink the trailing edge wedge. I follow videos by Jason Ellis on youtube, and he used the hand drill. My rudder TE wedge came out looking like ****. Half the holes were elongated, countersunk to a different depth, rough edge etc. Especially the two holes at the ends of the TE wedge. (I'm sure Jason's countersunk holes were better, I just apparently can't hold the drill steady).

When building the elevators, I was dreading to work with the wedge. So I decided to do something different. Instead of using the hand drill, I put the countersink cage in the drill press. I glued another unused piece of the wedge from the training project to the drill press's worktable. This is so I could have the csink cage contact the wedge at exactly the right angle. So basically I put my wedge on top of another wedge oriented the opposite way to make a rectangle out of two triangles. I had the csink cage fixed to the drill press with a piece of safety wire so the cage itself doesn't rotate.

This way, my countersink holes came out PERFECT. It felt very satisfying to prep it so neatly. Even the two outermost ones came perfectly round. Oh, I also set the drill press to the lowest possible speed. With the hand drill I was using 90 psi, which gives like 4000 rpm. Turns out, for countersinking it is absolutely unnecessary to blast it this fast, and slower speed gives a better result.

It may seem to you experienced guys like I'm stating incredibly obvious things. But I saw a couple folks who here who are newbies just like me, so maybe it'll help someone.

Andy

That's how I did as well. Works great.
 
Andy,

Glad you got this minor hurdle licked. There will be lots more, requiring little bits of ingenuity like this.

Don't be shy about sharing little successes and tips. Plenty more folks will come after you and benefit from what you learn as you go.
 
Someone sells ( I think Cleveland? ) a small jig which is machined to the correct angle for this to use in the drill press. That's what I used, and works like a charm.
 
The problem I think many run into is that the wedge is thin enough that the centering pin on the countersink comes through the back and hits the table before the cutter is complete. This will make the cutter wander giving an enlarged or oval hole.

I found the secret to be giving a place for the pin to go by either countersinking on a soft surface, over an existing hole, or in my case, hand holding the wedge while countersinking. (But then I am an old framer, accustomed to holding things while using power tools)

If you are concerned about controlling everything, then setting up a jig to take things out of play is a good idea.
 
I used my table saw to put an angled rabbit in a 12" piece of 1x2. I drilled a hole in the middle to clear chips and the pilot. I clamp that to the drill press and can drill both sides of the wedge in under 10 min.

You could also do the same with a scrap piece of wedge and hot glue or epoxy it to the board and add a fence along the narrow edge to keep things aligned. (It's nice to have the guide when doing longer runs and lets you use one hand to feed and one to drill.) There is some 25' of TE to countersink on the wings.
 
IMG_20200125_170713628.jpg

The setup I used on the rudder trailing edge. Made a "fence" from some of the scrap aluminum pieces sent with the kit.
 
While I have spent a lot of good money with the fine folks at Cleaveland Tools (highly recommended), your method of clamping is an excellent solution - at a lower cost too.

So good job Andy. And thanks for sharing.

While we're talking trailing edge...while you're online buying that countersink jig, take a look at the squeezer set for those rivets:
https://www.cleavelandtool.com/prod...4&_sid=6d2f23e29&_ss=r&variant=31588459905086

Works beautifully
 
I completely agree with the original poster - using a wedge under the wedge works well. I used a combination of wedged carpenters shims and flat drywall shims (I had stacks of each laying around after a home improvement project) to tilt the metal to the correct angle.
 
The cleveland tool is just one way to make things easy.

I second it's use for the trailing edges.
 
I tackled this a little different. I pulled the drill press out from the wall and as in the photo by No one , I rotated my trailing edge piece 90 degrees passing it next to the drill press tower. I then rotated the drill press table to get the wedge laying flat. Doing this you don't need any wedges or shims or extra tools. I then just used the #40 holes as a guide and drill stop cage . Fast clean and easy . Make a sample dimple on scrap the same thickness as the skin and random test to make sure the counter sink is deep enough but not too deep the the sample can move in the counter sunk dimple.
I don't know if my description is great but instead of moving the piece you are working on from side to side , you are going from in front of the press to the back so that tilting the bed to the correct angle the top surface of the wedge is perfectly flat and 90 degrees to the drill.
 
Just last night I was countersinking the wedges for the flaps, and turned it all on it's ear.

I clamped my cordless drill to the corner/edge of the table with the chuck hanging over, and took some safety wire to pull the cage to it's proper set rear position and to keep it from spinning. Then I put a small clamp on the trigger, so the drill kept spinning.

Then I just used both hands to pull the wedge into the bit, over and over. By looking down at the edge of the cage I could be sure I was making clean, full contact on the strip on all sides, and had a trash can even catching the chips as the fell out of the cage on it's side. Had them done in about 5 minutes and turned out great.

Lance
 
Last edited:
Wedge

After monkeying around with my own attempts trying to make a jig, I broke down and bought the cleaveland wedge tool. It worked great. If I still had a table saw and woodshop, I would have made my own out of wood, but I no longer have the tools to do that in a reasonable time frame. I think it was $30, and it saved me a ton of time.
 
After monkeying around with my own attempts trying to make a jig, I broke down and bought the cleaveland wedge tool. It worked great. If I still had a table saw and woodshop, I would have made my own out of wood, but I no longer have the tools to do that in a reasonable time frame. I think it was $30, and it saved me a ton of time.

I just ordered a short piece of the AEX wedge from Vans, to use in my drill press jig that I made.
 
Just read this again, and thought about the original post comment. You are using a hand drill.

I used a very nice hand drill for my first few holes, and I realized my mistake. Buy a really good drill press. I think this is the most important tool you will buy. I’m using a JET drill press. It cost a bunch, but compared to the engine or panel or fuselage kit, it cost nothing. Good drill holes are invaluable.
 
Can someone post a picture of the method they used to secure the countersink gauge to the drill press to prevent spinning.thanks
 
Not a big deal

No special tools used. I just drilled a couple of holes into the workbench, then laid the two pieces on top of each other (to make a rectangle as another poster said) then countersunk away with a hand drill. I made sure the small hole (being countersunk) was over the large hole of the other piece so the c/s bit was free to do its thing. The holes came out real nice

I did quick clamp the pieces to the bench to keep the pieces from moving. Drilled about three holes, moved the whole contraption, rinse and repeat.
 
Can someone post a picture of the method they used to secure the countersink gauge to the drill press to prevent spinning.thanks

Just a bit of safety wire from the cage to the column. You can also let it spin free but it’s annoying. It’ll stop as soon as it touches the wedge.
 
Cleveland jig

Here is a picture of how I set up the Cleveland wedge drilling jig on my drill press. Takes the guess work out and set up correctly produced perfect result.
i-4gXLLzC-XL.jpg


Here I used the Cleveland squeezer to set the rivets in the elev, TE. Make sure the spring on the special die set is at a right angle to the trailing edge. Each rivet is squeezed 3 times, first squeeze is about 1/3 on every 5th rivet then back and forth until all are set 1/3. Repeat that process only this time set the rivet about 2/3 and finally a 3rd time for the final set. This method produced a near pert straight TE.
i-L4JJCfF-XL.jpg

I use shot bags extensively throughout the build to hold things in please while I work on them.
 
While I have spent a lot of good money with the fine folks at Cleaveland Tools (highly recommended), your method of clamping is an excellent solution - at a lower cost too.

So good job Andy. And thanks for sharing.

While we're talking trailing edge...while you're online buying that countersink jig, take a look at the squeezer set for those rivets:
https://www.cleavelandtool.com/prod...4&_sid=6d2f23e29&_ss=r&variant=31588459905086

Works beautifully

Came back to read this. Rongawer, I can’t tell you how grateful I am for your mentioning of the set. Actually, I already have this squeezer set. It came in the standard kit from Cleaveland. But for whatever reason I completely forgot about it and built the rudder the old way with variable angle back riveting. I feel like an idiot. Now I’m actually looking forward to riveting that elevator TE - I love working with the squeezer; the rivet gun not so much. :) Right now I have all parts prepped and been waiting for a dry day here in Seattle so I can prime the parts in my driveway. In the meantime cutting foam ribs, counterweights, and making wooden clamps for the trim tabs folded edge.

Thanks again!
 
Can someone post a picture of the method they used to secure the countersink gauge to the drill press to prevent spinning.thanks

Check section 5.8 in the plans. They provide some pics there. It's literally just a piece of safety wire through the countersink cage and hooked to something. Doesn't need to be very strong, just enough to stop the spin. I just wrapped mine a couple times around the drill press post.

IMG_3120_small.jpg
 
Last edited:
Rivet squeezing technique

You mention squeezing the rivets 1/3 depth, with each rivet being squeezed 3 times.

Is there a mechanical disadvantage to resqueezing (is that a word?) a rivet?

I thought that once a rivet is squeezed, the mechanical properties have now been altered. In that, rivets are meant to only be squeezed once. I may have this completely wrong, but I thought I read that somewhere.

Anyone with a Mechanical Engineering degree out there?

Alternatively, if you are getting a good result (i.e. a straight TE), then any realized mechanical disadvantage may be worth the cost.

Thanks,
Jeff
 
Anytime you compress, or strain, a material such that you cause plastic deformation (an event where you squeeze or rivet gun a rivet such that spreads the shop head out) , you “harden” the material, which has increased the yield stress at the location of the imposed “strain”. Each time you harden the material further, you increase its resistance to any further plastic deformation. Excessive hardening can lead to material failure once the yield stress exceeds the material strength, and you end up with cracks forming. These cracks can form at a level much smaller than would be visible to the eye, but will eventually get larger as total strain increases; likely most visible around the perimeter of the shop head on a rivet that has been hammered excessively.

In practical terms, each time you squeeze or hammer a rivet, it gets harder and results in even less “squeezing” - you won’t smoosh it as much each subsequent time.

If you squeeze a rivet a second time to further “set it”, it’s probably fine; I’d get more concerned with subsequent events. It’s better to get the correct compression on the rivet performed in the initial event.
 
Last edited:
Jeff said: "Alternatively, if you are getting a good result (i.e. a straight TE), then any realized mechanical disadvantage may be worth the cost."

Ah, yes, the ole elevating form over function thing . . . :D

The reason you're getting a "wobble" in your trailing edge is the rivet shaft is swelling, stretching the metal around the hole, and, as stated above, getting harder so it ends up stretching even more as you finish driving the rivet.

Fresh rivets and a squeezer are probably best, as reported by many.

FWIW
 
Countersink depth for the trailing edge wedge

Any of you more experienced guys have a recommendation on what countersink depth gets the best results with the trailing edge wedge?

I've got a nice jig set up, but as others have pointed out in other threads, the wedge is so thin that countersinking deep enough to accept a dimple (as opposed to just the rivet head) will meet in the middle and widen out the hole. But I'm also afraid if I don't countersink deep enough the skin won't sit flat at the dimple and I won't get a nice TE.

So I'm stressing over whether I should countersink deep enough to take the dimple and not worry about the hole size or keep it on the shallow side and hope that squeezing the rivet mushes everything flat.

Thanks!
 
I set my jig up on a drill press. This kept everything aligned, and even though the pilot hole is somewhat widened, by using the press the countersink cage didn't wander around. For depth, I think I just set it at the standard 7 clicks past flush.
 
Last edited:
Back
Top