The Unsqueezer

[prestwich]

All right, I had to drill out some rivets yesterday. Dammit. I was so happy to be cooking along on this thing. Realized that I put eight rivets in the HS forward spar (-7A) that shouldn't have been put in yet. I was riveting the angle bracket stiffeners to the spars.

Four of those holes were supposed to accomodate nose ribs as well. Another four get some sort of attachment to the fuselage later on. Of course the dang plans don't tell you not to rivet all the holes, because the guys at Van's just love to laugh at us making stupid mistakes because we don't know until after the fact how the airplane goes together.

So drilling and snapping the heads didn't seem too problematic, and I was thinking, shucks, this rivet removal is duck soup. Then I tried to drive the remainder of the rivets out, and they were giving me fits. I couldn't fixture the thing so as to leave both hands free. I was trying to balance the rivet on top of a socket, so it'd have someplace to fall. Finally got that done, but didn't have enough solid metal under it. Stacked up a couple of yokes to give a solid backing, and still couldn't get 'em to budge, not to mention still found no way to clamp the workpiece so it wouldn't move all over the place. Well, I got one of 'em out.

OK, I wasn't using a real punch, I was using a broken drill bit, so maybe that's part of the problem. But I was whacking the tar out of it. Went to bed finally at 1:30, irritated.

So today I get up and think, by crackey (is it ok to swear in here, Spike?), I know how I'll get those pesky things out. I'll unsqueeze 'em.

Tonight after putting in a most of the afternoon and evening at my day job, I went into the machine shop and made myself some unsqueezing dies. A pin on one side, about 0.015" smaller than the rivet, and a pocket on the other side. Damn if they don't work sweet. I made them out of stainless, just for a trial, even though I know tool steel would be better.

They don't have the groove and the little locking ring, so they fall out of the pneumatic squeezer while I try to align everything. And, they're too short, so I had to stack three washers under each half. I just guessed at the dimensions while I was making them.

But, like I said, they do work. So did I just invent a cool new gizmo, or did I just spend an hour and twenty minutes making a crude prototype of something I could'a bought for twenty bucks?

(content edited for all audiences!)

[captain_john]

I just remove all the bad rivets from the tray before I install them!

CJ

[Spike]

...(is it ok to swear in here, Spike?)...

We prefer to keep it clean around here. With that said if you had used a subset of words the software would have let you know in an interesting manor

As for the tool, Id buy 'em for AD3 & AD4 rivets.

[johnk]

Nicely done!!, very creative idea

[jim_geo]

I just don't get it. Could you show us how it works?

[prestwich]

I just remove all the bad rivets from the tray before I install them!

CJ

I'm just amazed at the things experience teaches us. Since I'm a rank amateur, I'm still unable to tell the good ones from the bad ones before I squeeze 'em! I'll keep trying, though, and I'm sure my perception will improve over time

[prestwich]

Does this help? Imagine you've just drilled the manufactured head of a bad rivet, and snapped it off.

Now, instead of punching out the shank and shop head with a punch and hammer, which I found to be frustratingly awkward and difficult, you use these dies to squeeze it out.

The pin diameter is just slightly smaller than the rivet diameter, so it won't ruin the hole. The hollow cup on the other side surrounds the shop head, and is deep enough to receive it as it is pressed out. Like I said, the dimensions I used need some modification. Mostly, the cup side needs to be longer, and the cup deeper.

[cjensen]

mmm...longeron yoke...i'm so jealous!

[prestwich]

mmm...longeron yoke...i'm so jealous!

Hey Chad, nice looking, aint she? Good for me you had the common sense to turn down my loan offer -- turns out this baby is good for more than just longerons! I've already used it on the HS. G' 'head, pick yerself up one! What's another buck and a quarta?

[cjensen]

yeah, yeah, yeah...i'm gonna look for a deal at SNF this weekend. if i don't find one, i'll get one when i get back. i'll have to have it to rivet the rear spar with the squeezer.

[Wicked Stick]

Actually, I think they call it a "C" yoke. But everyone call's it a Longeron yoke cause it fits nicely around the longerons.

Anway, I think that's a WAY COOL idea, and I would consider having a set for my squeezer should you choose to make and offer them to others.

As for those other times when you need to bang out a bad rivet in a place other than where you can use a squeezer, here's a few other hints that would help.

Use a #41 or #31 drill bit (which are slightly smaller than the hole size.)
This way you can opt to drill all the way through and you won't enlarge the hole if your off a little cause the bit is smaller. Then it will punch out much easier as well. The other key to this is to make sure you put a heavy bucking bar as close to the backside of the hole as possible and YES, use a flat straight punch and dead blow or heavy hammer to "tap" it through. Sometimes it's hard to do this and hold the bar at the same time..but that's what friends are for

Keep up the great ideas, and keep at it. Find another builder in your area and help each other out.. It makes a big difference.

[cjensen]

Actually, I think they call it a "C" yoke. But everyone call's it a Longeron yoke cause it fits nicely around the longerons.

i think they are all "C" yokes, the longeron is called a flange yoke if i remember correctly...

[Wicked Stick]

Actually, I think they call it a "C" yoke. But everyone call's it a Longeron yoke cause it fits nicely around the longerons.

i think they are all "C" yokes, the longeron is called a flange yoke if i remember correctly...

It's been a very long day here at work .. thanks for the help Chad.

[cjensen]

understand that! won't hold it against ya!

[prestwich]

All right you guys,

Thanks for the votes of support. I'll go ahead and make up some "beta" Unsqueezers and we'll give 'em a try. I've had trouble finding the little spring collars that keep them in the yoke, maybe because I don't know what those little gizmos are called. Any help on that?

Jon

[captain_john]

I think they are 3/16" roll pins, cut down to size???

http://www.smallparts.com/products/descriptions/sps.cfm

Sign me up for a beta unit!

CJ

[N200PF]

NO DOUBT!!! I'll buy a set and let you know how they work!

They'll get PLENTY of use in my shop!

- Peter

[prestwich]

I think you might almost be right, CJ. I think it's a roll pin. But not cut down in length, but short to start with, because it looks like it has lead-in tapers at both ends. And light gauge stock, too. Much thinner walls than a typical roll pin.

[rvbuilder2002]

You missed a step required to easily remove rivets from thicker material buildups like you have in the stab spars.
Because the rivet expands tightly against the interior of the hole you need to relieve this some how to have it drive out easily.
After drilling and poping off the rivet head, Drill down the center of the rivet with a smaller size drill (use 3/32" for an 1/8" rivet). Don't drill all the way through. Now use a 3/32 pin punch to drive the rivet out. Because you are driving against the opposite end it will stretch the length of the rivet which in turn will reduce the diameter. This will allow the rivet to drive out easily if you drill deep enough. If you go too deep and drill all the way through, then use a sharp side cutters to grab what is left of the shop head, twist it back and forth a couple of times to break it loose, then pry it out of the hole.

I have an unsqueezing tool similar to yours that I made many years ago but I rarely have to resort to using it.