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Well I join the reorder group….

JeremyL

Well Known Member
It’s official, I have joined the “screw up a part and reorder it” group. Which I’m sure most all of us are in. The dreaded TE wedge countersinking got me. I’m not sure what happened, as to why it chattered so much but it did and vans tech support said “replace.” I was using the Cleveland wedge drilling device, on a drill press running at 450 rpm. My fix for this is going to be….. drop the rpm to the lowest it will go (300) rpm, I have purchased the single flute countersink bit, and decrease the depth by about 2/ 1 thousandths. I have included a couple pictures of the mess and one I thought was interesting from vans tech support. If you have any pointers, etc, I’d love to hear.
 

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Drill/deburr a scrap piece of mild steel the same diameter as the hole for the counter sink.

Clamp that underneath the aluminum and make the holes line up. The mild steel will serve as a guide for the countersink and will prevent wondering/chattering.

Aluminum will work too, but you will have to make a new one every so often as the hole becomes oblong from use.
 
Single flute will address the issues. It is only AFAIK a 1/4 drive not the 1/4-28 thread, but it really is no issue. I find a good variable speed hand drill gave me less chatter. You can easily look at the CS to see if it is aligned.

While drill presses seem like a good precision way to do all things, they have their own limitations. Details spared.

Variable speed hand drill with single flute. Practice on something else and mind your hand grip technique. I always held the drill with the grip up, not down like a pistol. Forearm line of action is more linear with the bit that way - just me . . . maybe mental but what ever works.

Oh- and mineral spirits or Tap-Con or kerosene as a lubricant can get smooth cutting with aluminum if nothing else works.
 
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Post number 2 has the answer. Anytime that you countersink to a near knife edge hole or beyond, the pilot can’t keep the bit centered. You need a guide, and the backup piece will do that if you clamp it to the work piece. That will work with a hand drill or with a drill press. On a drill press that doesn’t have excessive play, you can simply clamp the work piece down to get a good result.

Different bit types with some technique thrown in can improve the results, but IMO, never as good as stabilizing the pilot or the workpiece.
 
Drill/deburr a scrap piece of mild steel the same diameter as the hole for the counter sink.

Clamp that underneath the aluminum and make the holes line up. The mild steel will serve as a guide for the countersink and will prevent wondering/chattering.

Aluminum will work too, but you will have to make a new one every so often as the hole becomes oblong from use.

This would be a good idea, but for me using the Cleveland device, it won’t workout. Excellent advice though if I didn’t have the device. Thank you.
 
Single flute will address the issues. It is only AFAIK a 1/4 drive not the 1/4-28 thread, but it really is no issue. I find a good variable speed hand drill gave me less chatter. You can easily look at the CS to see if it is aligned.

While drill presses seem like a good precision way to do all things, they have their own limitations. Details spared.

Variable speed hand drill with single flute. Practice on something else and mind your hand grip technique. I always held the drill with the grip up, not down like a pistol. Forearm line of action is more linear with the bit that way - just me . . . maybe mental but what ever works.

Oh- and mineral spirits or Tap-Con or kerosene as a lubricant can get smooth cutting with aluminum if nothing else works.

Thank you bill. I do indeed suspect that it is a pilot hole utilizing the 3 flute bit due to one side of the wedge was able to be countersunk with virtually no chatter. The chatter did not appear until I flipped the wedge over and tried to do the opposite side. So my new plan will be to use the 3 flute on one side , flip the wedge over and then use the single flute. The reason I would use both and not just the single flute is a minor design flaw in the single flute where the pilot breaks off on about 10% of the products. So I hope to minimize side load on the single flute. But we shall see .
 
I would check your drill press for levelness/perpendicular to the chuck, it looks like, especially in the second picture, you are not hitting flat when you countersink. The countersink is wider on one side than the other. Maybe its the tool not flat, idk.

I am surprised they said replace, I could swear I've seen posts where they say its acceptable because it is sandwiched between two skins and has proseal in between.

I don't understand Vans picture, are you actually riveting to the countersunk wedge or are two skins doing most of the structural work and the TE wedge is just in between?

Picture of the tool I made from a practice kit to countersink the wedge.
 

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I would check your drill press for levelness/perpendicular to the chuck, it looks like, especially in the second picture, you are not hitting flat when you countersink. The countersink is wider on one side than the other. Maybe its the tool not flat, idk.

I am surprised they said replace, I could swear I've seen posts where they say its acceptable because it is sandwiched between two skins and has proseal in between.

I don't understand Vans picture, are you actually riveting to the countersunk wedge or are two skins doing most of the structural work and the TE wedge is just in between?

Picture of the tool I made from a practice kit to countersink the wedge.


I noticed that too, but that only happened on the back side countersink, so I assumed it was because the pilot wasn’t secure. But I will check the level when I get home just to be sure. I am also surprised they said replace it, seeing other pictures and similar problems but I dunno. To be honest I am sure it would be fine to install but it would bug the heck out of me if I did and they said replace. I’ll paste the quote of exactly what tech support said in regards to that picture….

**Tech support said:** “I would like to point out additionally, that the countersink depth for a nested dimple is a little different than what most initial builders might think. This diagram shows/indicates the feature:”
 
The Cleaveland jig although it holds the AEX at the right angle to keep the countersink perpendicular to the AEX surface, does NOT center the countersink pilot (thru hole way too big). So any play in your countersink cage and drill press spindle will show up as chatter in the cut. My preference is as previous advice, make a sacrificial backup piece (I made mine from aluminum angle) that has a #40 drill hole to keep the countersink pilot centered.
 
It looks like your countersinks were too deep. You should be setting the cage to flush PLUS 7 clicks. In other words, the rivet should sit 0.007" below the surface. see section 5.5 and the drawing van's sent is why. If you do this, the center of the pilot just barely avoids busting out the other side. You only have a couple of mils to work with here.

You may also not be using enough pressure. I've found countersinks like to go slow and take big bites. YMMV.

If you're having trouble with part wander on the jig, try putting a piece of masking tape on the jig. It'll grab the AEX wedge once you start pushing on it.
 
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It looks like your countersinks were too deep. You should be setting the cage to flush MINUS 7 clicks. In other words, the rivet should sit 0.007" above the surface. see section 5.5 and the drawing van's sent is why. If you do this, the center of the pilot just barely avoids busting out the other side. You only have a couple of mils to work with here.

You may also not be using enough pressure. I've found countersinks like to go slow and take big bites. YMMV.

If you're having trouble with part wander on the jig, try putting a piece of masking tape on the jig. It'll grab the AEX wedge once you start pushing on it.

I just reread 5.5, and it states that the countersink has to be deeper. They say to then set the micro stop 7 clicks deeper not shallower. Mine indeed was set to 7 clicks past flush. The masking tape idea I will definitely try.
 
The Cleaveland jig although it holds the AEX at the right angle to keep the countersink perpendicular to the AEX surface, does NOT center the countersink pilot (thru hole way too big). So any play in your countersink cage and drill press spindle will show up as chatter in the cut. My preference is as previous advice, make a sacrificial backup piece (I made mine from aluminum angle) that has a #40 drill hole to keep the countersink pilot centered.

I’ve definitely learned how important having somewhere the male pilot to go into is. So I may tinker (since I have to wait for a new wedge) with putting properly cut dowl rods in the holes of the Cleveland tool and then drilling a #40 in that.
 
I just reread 5.5, and it states that the countersink has to be deeper. They say to then set the micro stop 7 clicks deeper not shallower. Mine indeed was set to 7 clicks past flush. The masking tape idea I will definitely try.

d'oh that was my mistake. i'll edit the other post. you are correct - it should be DEEPER. I haven't had any holes in the TE wedge get that big in my build. They all just barely kiss at the shallow end with a bit of material left on the thicker end.
 
d'oh that was my mistake. i'll edit the other post. you are correct - it should be DEEPER. I haven't had any holes in the TE wedge get that big in my build. They all just barely kiss at the shallow end with a bit of material left on the thicker end.

No worries, I honestly kind of got really excited for a second, I was like omg no wonder it looks like a bear was digging for berries in that hole hahaha
 
I did my TE wedge with a hand deburring tool. Not the fastest approach but I got some real nice countersinks.
 
Which tool and how did you get the proper depth for each hole?

The normal deburring tool with the offset handle. I dropped a rivet in each hole to check depth. My calibrated eyeball was sufficient. TE came out way better than I could have anticipated which i was grateful for. I was very anxious about riveting it as it was the first time during the build where one slip up would ruin more than a single part.
 
The normal deburring tool with the offset handle. I dropped a rivet in each hole to check depth. My calibrated eyeball was sufficient. TE came out way better than I could have anticipated which i was grateful for. I was very anxious about riveting it as it was the first time during the build where one slip up would ruin more than a single part.

Interesting, yeah I know what you mean with the anxiety
.
 
This is one of those things that many have come before and built perfectly good airplanes (we think). I think Bill's comments pretty much match what I would say. A little craftsmanship may be required. I did a few in a high precision setup (we'll leave it at that), and transitioned to a pretty good fixture in a drill press, and touched up a few with hand tools.

Do what is necessary. Test, try, repeat. By the last hole, you'll have it figured out, but the rest will probably be fine :).
 
This is one of those things that many have come before and built perfectly good airplanes (we think). I think Bill's comments pretty much match what I would say. A little craftsmanship may be required. I did a few in a high precision setup (we'll leave it at that), and transitioned to a pretty good fixture in a drill press, and touched up a few with hand tools.

Do what is necessary. Test, try, repeat. By the last hole, you'll have it figured out, but the rest will probably be fine :).

True, I’m just going to have to mess with it and hopefully it comes out good enough.
 
RV-10 Rudder TE

I did my first trailing edge a week ago. Used the Cleaveland jig and air drill. Tried to get it deep enough for the skin to sit flush. Went too deep, too much chatter from the hand drill and ruined the piece.

I had a TE for the elevators so I used that last night. Used the Cleaveland jig in a drill press. The speed was pretty high but it made perfect counter sinks. Wasn't able to get the last 3 holes so I used the hand drill again and got a little chatter, that I was able to clean up on the DP once I moved things around.

I was wondering if the DP should be fast or slow so I stuck with the setting and it worked fine.
 
The normal deburring tool with the offset handle. I dropped a rivet in each hole to check depth. My calibrated eyeball was sufficient. TE came out way better than I could have anticipated which i was grateful for. I was very anxious about riveting it as it was the first time during the build where one slip up would ruin more than a single part.

My screw up on the rudder was a big one and I scrapped the entire thing. I managed to figure eight every single hole in the trailing edge. There was no coming back from that. $325 later I had all new parts and just recently started building the second rudder.

I just countersunk my rudder TE late last week. I simply put the TE point even with a drilling board (not hanging off the end) and used my hand pneumatic drill with the Cleaveland Tools reduced pilot and a 3-flute C/S bit. This allowed the countersink cage to stay level with the surface of the TE.

I avoided chatter by going with a slow speed and moderate. If I heard that banshee wail I backed off the speed until it quieted down. Most of the time I didn't have chatter. My countersinks were perfect.

Regarding the C/S depth, I did some test coupons on some scrap 0.016 in. skin (from my messed up #1 rudder) and the cutoff TE from the new one. I also had a 10 minute conversation with the mother ship about the nuances of nested dimples in countersinks. Long story short with thin skin I settled on the rudder C/S was one that was flush with a AD3 rivet because it was the best, tightest fit. It is preferable to have the sides of the dimples contact the C/S surface instead of having the skin lie flat on the surface of the TE. Doing it this way also left a small but distinct bearing surface on the aft end of the hole. A 0.007 in. underflush C/S left a knife edge.
 
Hmmmm……….

I got to thinking about it, I am using vhb tape for my TE. Some use pro seal or epoxy. So my thought is, the countersink depth cannot be that critical here as to completely nest the dimple because the tape and pro seal would lift the skin Atleast a few thousands. Thus creating a good looking TE gap basically regardless of the countersink depth. Unless I’m missing something here, I’m just going to countersink you a depth flush with the ad 3 or maybe, maybe 1-2 thousandths deeper.
 
Another countersinking idea

I took a small piece of aluminum, the same thickness as the skin. Drilled a couple #40 holes in it then dimpled to form a thickness gauge. To countersink the VA140, I took a piece of aluminum angle, 1/16 from the aviation section at Home Depot. I then match drilled it to a segment of VA 140. I then clecoed the VA140 to the aluminum angle. I was able to countersink both sides of the wedge with minimal chatter.

I have been asking myself if my countersinks are too deep. The 3/32 hole in the middle certainly ends up larger that 3/32. The only way to prevent chatter is to have a significant backing. I decided that having the two sides of the skin nest with the wedge was more important than having the rivet exactly fit the side walls.

When it was time to rivet up the rudder trailing edge, I glued it up using the aluminum angle to keep it straight while it set up. I then used the angled squeezer dies and riveted it all together with my pneumatic squeezer. Rudder came out as straight as I am able to see.

Getting ready to do the same for the elevators. Any thoughts on the oversized holes?
 
I took a small piece of aluminum, the same thickness as the skin. Drilled a couple #40 holes in it then dimpled to form a thickness gauge. To countersink the VA140, I took a piece of aluminum angle, 1/16 from the aviation section at Home Depot. I then match drilled it to a segment of VA 140. I then clecoed the VA140 to the aluminum angle. I was able to countersink both sides of the wedge with minimal chatter.

I have been asking myself if my countersinks are too deep. The 3/32 hole in the middle certainly ends up larger that 3/32. The only way to prevent chatter is to have a significant backing. I decided that having the two sides of the skin nest with the wedge was more important than having the rivet exactly fit the side walls.

When it was time to rivet up the rudder trailing edge, I glued it up using the aluminum angle to keep it straight while it set up. I then used the angled squeezer dies and riveted it all together with my pneumatic squeezer. Rudder came out as straight as I am able to see.

Getting ready to do the same for the elevators. Any thoughts on the oversized holes?

If they look like the holes in my first post/pictures then they are too big and that’s from vans tech. Check out the last picture in the first post about how deep to countersink. If I remember correctly I went with flush plus the 7 clicks and called it good. Check my build log if you want.
 
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