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Countersunk too deep...

Well, started yesterday and already made my first error, actually 2. Yesterday I got to the point where I needed to countersink the VS-1008 doubler. I had set up the countersink cage on a piece of scrap material but I messed up. I think I wasn't pressing hard enough on the scrap piece, and so my cutter was out way too far. When I countersunk the doubler, I pressed harder and all of the sudden had a really deep hole. After cussing a bit, I adjusted and did the second hole and it was still too deep (Just getting a feel for the tool here I guess). From the 3rd and subsequent holes, the countersinking is fine.

So the question is - Do I need to scrap this doubler and order a new one? And if not, what is the process for using the over-countersunk hole?
 
How hard you press shouldn’t make that much of a difference, as long as you go until it stops moving, something around 0.001” at best. You may have the same issue I had: the spring in the micro stop could have too long of a compressed height. I ended up replacing the part that was affected.

You can test this by removing the countersink and pushing the cage down until it stops and then push really hard. If it jumps another step you have the problem. All you need to do is disassemble the stop and clip one or two turns off the spring. Grease the bearing while you are in there and you should be good to go.

I’ll let others weigh in on how to address the problem. Ultimately it needs to be something you are comfortable with.
 
Might check to make sure the cage on the countersink isn't bottoming out on the drill chuck... the next time you install the CS the internal stop might be the one it uses and there might be a nasty surprise! :eek:
 
Countersink cage

Might check to make sure the cage on the countersink isn't bottoming out on the drill chuck... the next time you install the CS the internal stop might be the one it uses and there might be a nasty surprise! :eek:

That would be my guess as well.
The other explanation involves Murphy. He has burned me a few times as well. Now I almost always under countersink and dress the final by hand. I don't trust any of my three cages 100%.
 
It was more a matter of my inexperience than anything. When setting up the CS bit in my spare stock, I wasn't getting the full effect of the bit (Not holding it right, not going straight in, whatever, the problem was). So when I got it adjusted where I liked it, in reality I had it adjusted incorrectly. When I went to the actual doubler, I guess I got it pressed firmly enough / gave it enough time to work, and voila, super mega huge hole LOL. It's a lesson learned. I will definitely be more cautious in the future when it comes to removing material.
 
i have noticed that depth of cut will vary a bit if you don't tighten lock ring after each adjustment.
 
Same problems

I have also had issues with inconsistency in the cages, despite making test holes everytime. The advice that helped me the most is to have a piece of backing material behind the piece you are countersinking, especially if it is a thin piece. It's time consuming, but has saved me a lot of problems. I've replaced three parts in the the empennage due to poor countersinking. I also have started countersinking shallow, then sneaking up on it one notch at a time.
 
Do I need to order a new doubler?

Hi all.

I am just getting started and all was going pretty well until I got to the machine countersinking of my vertical stabilizer doubler.

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This is a pretty thick piece where they are no where near the back side of the material. My gut says that the strength has not been compromised but I know getting a good set will be harder to do.

I read that I could make a tiny spacer to make sure I get a good squeeze when I do eventually set these.

Keep going or order a new doubler?

Thanks!
 
It can be a bit "cagey"

Yes, that is exactly what I mean.
In fact, the countersink cage can give you a very false sense of security when it comes to precision countersinking.
The only way I know of getting precise countersinks with an adjustable cage is to set it up on exactly the same piece of aluminum as the part that needs countersinking.This is simply not possible in most cases.
For example when you countersink flanges on the spar, you'd need to set up a bent piece of aluminum to get a precise setting.
Take wirejock's advice and use that cage contraption for a quick pass on a row of countersinks and then give it a final "shave" with just a countersink bit in your electric slow drill. Before long you won't touch that cagey device anymore and just countersink by feel. You'll be spot on most of the time and twice as fast as using that useless countersink cage.
 
Will see what the mothership recommends

I sent Vans a note and the photos about my slightly deep countersinks in the VS-1008 (referenced previously). Will let everyone know what they recommend.

------------------
(Asked Vans)

Would you recommend...

1. Replacing the doubler (I don’t mind the rework, but I’m worried about the match drilling. Seems it would be easy to make a mess of the existing final size holes in the thinner layers below when trying to match drill into the much thicker doubler?)

2. Use a trick I read in the forum about creating a tool rivet as a spacer so I get a good squeeze on the recessed rivets.

3. Given the thickness of the doubler, can I go up one size to a AN426A5-7, re-drill and re-countersink to the larger rivet?

4. Something else??
 
I sent Vans a note and the photos about my slightly deep countersinks in the VS-1008 (referenced previously). Will let everyone know what they recommend.

------------------
(Asked Vans)

Would you recommend...

1. Replacing the doubler (I don’t mind the rework, but I’m worried about the match drilling. Seems it would be easy to make a mess of the existing final size holes in the thinner layers below when trying to match drill into the much thicker doubler?)

2. Use a trick I read in the forum about creating a tool rivet as a spacer so I get a good squeeze on the recessed rivets.

3. Given the thickness of the doubler, can I go up one size to a AN426A5-7, re-drill and re-countersink to the larger rivet?

4. Something else??

It's hard to tell but from those pics it looks like nearly every hole is countersunk too deep. I don't have the spec in front of me, but from memory, the rivet should sit -0.00 - +0.005" in the hole. In other words, you should be able to just catch the edge of it when running your scale over it (or clear with no space). That's generally a small halo around the rivet head.

You don't want to go below the surface because it makes it hard to back up the head of the rivet and it ends up creating a gap.

How are you setting up your countersink? You should have complete repeatability here to within 0.001". If you're having to rely on pulling it off by feel you'll get inconsistency. You should be able to push fairly hard and wait for the drill to stop making chips and have the hole you want. I use a scrap piece of 1/4" to set up the cage.

If you have the same Yard Store cages I have, you might have the spring problem I had where it shipped with a spring that was too long and would fully compress and then collapse under enough pressure and go deeper. Clipping a couple of turns off the spring fixes the problem.
 
Vans response was to re-order the doubler

So after sweating my first mistake and how to fix it, Vans recommended that I purchase a new doubler.

First page of the plans and I'm replacing stuff already :) Onward.
 
So after sweating my first mistake and how to fix it, Vans recommended that I purchase a new doubler.

First page of the plans and I'm replacing stuff already :) Onward.

Don't let that make you feel bad - you are setting the tone for the rest of your build, making honest and realistic decisions about your own work. It's good. The alternative is to let things slide...and slide...and slide...until you let something important slide, and then we have to read about in an NTSB report. That's not good.

If it helps, I was almost three days into my emp build before I ruined a spar and both doublers. They now hang on my wall as a reminder for me to think twice before picking up a drill. :D
 
So after sweating my first mistake and how to fix it, Vans recommended that I purchase a new doubler.

First page of the plans and I'm replacing stuff already :) Onward.

Don't worry about making misteaks (sic) it is part of the process. Now you'll have a nice piece of aluminum to practice countersink settings on. (I'm on my second doubler too, but it was from homemade beer that I didn't realize was that strong. Now no brews until all tools are put away...)

You can use the opposite end of a digital caliper as a depth gauge. Set your countersink stop to the estimated depth, countersink on your "new" piece of training metal. Then drop a rivet in and verify a 0.007 countersink. Make sure to lock the thumbwheel well, and check your work often. Keep the underside of CS cage clean to prevent shallow CS and use a piece of wire to keep cage from spinning. (as my image showed)
 

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Don't worry about making misteaks (sic) it is part of the process. Now you'll have a nice piece of aluminum to practice countersink settings on. (I'm on my second doubler too, but it was from homemade beer that I didn't realize was that strong. Now no brews until all tools are put away...)

You can use the opposite end of a digital caliper as a depth gauge. Set your countersink stop to the estimated depth, countersink on your "new" piece of training metal. Then drop a rivet in and verify a 0.007 countersink. Make sure to lock the thumbwheel well, and check your work often. Keep the underside of CS cage clean to prevent shallow CS and use a piece of wire to keep cage from spinning. (as my image showed)

I did the same and it worked well. I found you had to check the depth often. I used a drill press when ever I could. Still found depth tended to drift.
 
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