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Frustrated: Squeezer bending rivets

Girraf

Well Known Member
Friend
I'm most of the way through my empennage and I'm still struggling to get my squeezer to to not pull the shop heads as they set. Biasing the tail towards the throat side of the sets seems to help but its not always possible to make that happen because the nose of the yoke inevitably hits the web of whatever is being riveted (see photo).

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Normally I would set the rivet with the yoke perpendicular to the spar (as in the photo) but I also tried a two step set process where I'd hold the squeezer as parallel to the spar as I could for half a squeeze (with the yoke to the right), then finish the squeeze with the yoke to the left all in the name of trying to get an axial squeeze. That helped a little, but still not as good as I think it it can be.

I've also played with some rotating motion of the squeezer body as I set to compensate for any yoke flex. Most of my work is with a 3" yoke and I am very deliberate in my process with alignment and trigger work. With a 4" no hole yoke, this behavior gets even worse. I am also using the quick change pins, and these have a very, very small amount of play in them.

I'm really frustrated that after most of the empennage I still don't have that confidence that when I pull the trigger, I'll get a great rivet every time, which is my expectation. :mad:Perhaps that expectation is too lofty...
Just tonight working on the left elevator trim tab attachment spar, I had to redo more than 50% of my rivets, some more than once. That kind of efficiency is unacceptable.

Is it worth grinding down the nose of the yoke a little bit to be able to reach deeper?
 
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Those shop heads look pretty darn good to me, from what I can tell. Fwiw, I did grind down the nose of my 3” yoke a bit
 
I would guess that the yoke is deforming slightly. A beefier deep yoke or a yoke with a shorter throat will reduce/eliminate that.

I have two hand squeezers. The one with the 1.5" yoke makes perfect shop heads. The 3" yoke deflects some and doesn't produce "plumb" shop heads.
 
Yoke

I would guess that the yoke is deforming slightly. A beefier deep yoke or a yoke with a shorter throat will reduce/eliminate that.

I have two hand squeezers. The one with the 1.5" yoke makes perfect shop heads. The 3" yoke deflects some and doesn't produce "plumb" shop heads.

Agreed. The shop heads look good. Always choose the shallowest yoke for the job and use the thickest set possible on the shop side.
OR, get really comfortable with gun and bar. Lots of places on the plane where a squeezer won't work. If fact, quite a few where you need a double offset.
 
And I agree as well. The shop heads in the photos are fine.
Some deep throat squeezer yokes flex more than others causing the faces of the rivet sets to mis-align slightly which will cause the shop head to vary in thickness slightly.
As long as the head is still centered and the thinner side of the shop head is not thinner than the MIL Spec requirement (none of yours look anywhere close to being too thin) then they are fine.
 
Yep them rivets look pretty dang good. When I was new to the squeezer I remember this too, when squeezing I find that focusing the vast majority of my attention to get the rivet in the center of the set on the yolk helps a lot.
 
I can always trust the VAF community to put me at ease! The pancakes (shopheads) are nice and even, they just happen to be setting slightly to one side (always toward the flange edge in my case), enough that I've been hemming and hawing on whether they should stay or go.

I decided that I would nibble away at some of the material on the tip of the yoke to help my cause. Being able to position the rivet closer to inboard edge of the set helps alleviate the lateral force that seems to pull the shop head toward the throat of the yoke.
 
+1 on trimming the yokes when necessary

I have found that I can use my flange yoke for a large number of rivet squeezing tasks to the point that I prefer that yoke whenever possible. it has about a 2 inch clearance but also has extended set inserts on both ends of the yoke that allow the sets to get over and under the flange and down on both ends of the rivet. It works especially well when you have hinges jutting outward from the rest of the flange because it provides enough clearance from the hinge rungs and a short enough moment to keep it from flexing any more than any other yoke IMHO.

That said, I currently own three separate yokes, and I have ground down the fronts of each and everyone of them to address the clearance issue against the web of the part just as you show in your pics. I have even had to slightly grind down a few rivet sets along the way for exactly the same reason.

I also agree that your rivets look good to me. So grind down those yokes a bit to get the clearance from the web that you need and KPR. If corrosion is an issue where you live (it's not for me) then spray some primer on the exposed metal afterward. You will get over the "sinking" feeling of potentially "ruining" a fairly expensive hunk of metal (the yoke) after you grind it down and then use it successfully to set another quality rivet. From then on you won't even think twice about modifying some of the tools as you progress, as long as you do some testing with it before you apply it to the real thing, just to be certain that it will do the job correctly.
 
When I first started on my RV-10 emp kit, I had similar problems with my squeezer, while building the first piece (vertical stabilizer). Turns out the adjustable set holder (i.e. the part that actuates) was bent. Here's what I did:

I removed my adjustable set holder piece and chucked it into my drill press and spun it up. It was easy to see that it was in fact bent. My tools were ordered as part of an Isham Tools RV kit (planetools.com), so I called and they replaced it free of charge. This helped solve my issue.

Bonus Tip: When using the squeezer, I always make sure that more pressure is on the factory head side of the rivet, just like when bucking rivets with a rivet gun. It's the same, whether or not it's a flush or universal rivet. Always push harder on the factory head side. It helps keep the rivet in place while it's mushing and you'll end up with a nice round shop head. Keep practicing. I'd never build an RV without a pneumatic squeezer.
 
I find that I have more control with my Tatco hand squeezer. In general I try to use it versus my pneumatic squeezer. Also, make sure you check the length of your exposed rivet with a gauge. A rivet that is too long will bend over. For -4 rivets I have to use my pneumatic squeezer.

When using the pneumatic squeezer make sure you keep the plunger aligned with the axis of the rivet. You can feather the trigger a little to position the squeezer slightly but it can be difficult. Usually you hit the trigger and you get what you get. If you have the plunger side on the flush side of the rivet it takes care and practice to get a perfect shop head. Try feathering the trigger so that you can make sure you are still aligned along the axis of the rivet as you get close to compressing the rivet.
 
Kudos to you for sticking with the squeezer for so long.

But the gun and a tungsten is way more forgiving (better?) for -4 rivets and larger. I only use my squeezer on -3s and smaller (if I use it at all), and yeah everything the guys said above will help you if you remain wedded to your squeezer.....but you dont have to.
 
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I too sometimes have to struggle with my squeezer. Sometimes its a bit temperamental. (I too am using the Isham adjustable rivet set) I have good success with setting AN426 rivets as getting a good set is all in getting the die perfectly flat on the factory head, and making sure the rivet tail is centered on the die before squeezing. Squeezing AN470 rivets are sometimes a bit more tricky as it is more difficult to get the cupped rivet set sitting perpendicular and square on the factory head. No question that I have better success bucking (And you become a master if you skin the wings yourself)but it can be a bit hard on light material with a 3x gun. Sometimes I've started bucking the AN470 rivet with a hit or two and then squeezed it to finish it off. Always turns out perfect that way.
 
I too had the same problem starting out. One thing that helped is to secure the work piece so it can't move when you squeeze. Another tip I came across here is to the scuff the surface of the set, a sidewalk worked great.
 
I have ground the nose of my yokes to match the radius of the largest diameter dies I have.

I absolutely hate grinding on a nice tool, but in this case it is/was necessary. It will not fit or leave a mark otherwise. The material removed is not a stressed area.
 
with my pneumatic squeezer i have noticed that setting the rivet with the face of the die perfectly square to the shop end of the rivet does not make as nice a finished rivet as slightly moving the back of the gun in the direction of the closed side of the c yoke. i suppose this is because of a little flex in the 3''
3'' yoke.
 
Not sure if this is just me or not, but I find that I get much better results if I do not have riveting tape (3M magic tape in my case) on the manufactured head. It seems odd to me that it would make much of a difference but I've found it to be extremely repeatable. It may be in the same train of thought as scuffing the sets. Perhaps the tape reduces friction a bit making the set more susceptible to slip.
 
90% of my rivets that folded over were due to the rivet being slightly too long. Don't be a slave to the rivet callouts in the plans. If you can get a milspec sized shop head with a 1/2-size smaller rivet length (which I found often to be the case) then you might find yourself having more luck. Having said that, if your yoke is actually bending, I'd recommend you get a better yoke. It would be well worth your investment over the long course of the build.
Good luck.
 
Anyone care to post a picture of their nose jobs on the squeezer yokes?

Also, any suggestions as to which is thin nose yoke is more useful: 1", 2.5", or 4"
 
Make sure your not accidently hitting the hinge as the squeezer is pulling tight.
I did not read all the post so forgive me if I have repeated a post.
 
Make sure your not accidently hitting the hinge as the squeezer is pulling tight.
I did not read all the post so forgive me if I have repeated a post.

I actually almost did this and crushed a hinge loop. Luckily I caught it in time and avoided destroying it.

Grinding the nose of my no hole yoke and my 3? yoke has helped a lot with getting better quality shop heads. I would say the 3.5 length rivets are just a shade too long making it quite difficult to get just the perfect shop head. I guess I?ll have be ok with acceptable and not perfect!
 
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