Back Rivet Set

A place to discuss workshops and the use and desirability of tools.
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kennyw
Class G
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Joined: Wed May 14, 2014 2:16 am
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Back Rivet Set

Post by kennyw »

Had a little trouble back-riveting the lower rudder hinge brackets on the vertical Stab rear spar this morning.

I was using a 2X gun with an Avery back-rivet set. The rivets are AN426-AD4. And, the flow restrictor I installed on the gun doesn't really seem to do anything. So, the pressure at the gun was about 90psi. The rivet set has a polished end that seems to me to be slightly convex. The set seems to slide right off the rivet, pushing the shop head off, giving it a definite slope. 2 were bad enough to have to be drilled out.

I have a couple of questions:

1. What should the line pressure at the tool be? what kind of flow-restrictor/regulator do you use at the tool? The one I'm using came with my basic RV tool kit from Avery, (15 years ago).

2. Shouldn't the face of the back-rivet set be flat, not convex? Can I grind it flat and re-polish it?

Thanks in advance,


KennyW

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bruceh
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Post by bruceh »

The added length of the back rivet set requires more air pressure over a flush rivet set (mushroom type). When ever I had problems setting any rivets, the first thing to try to fix the problem is to adjust is the air pressure. Long rivets and long rivet sets (single & double offsets) seem to really require the air pressure really be cranked up.

I have the small adjuster on the rivet gun and I never used it. I always went straight to the regulator on the air compressor and set it from there.

How convex is the face? I'm pretty sure it should be flat, or really near flat. It can be a challenge to hold the gun perfectly perpendicular to the rivet. Try sneaking up on the rivet gun trigger just to get the shank of the rivet to expand in the holes and you should be able to quickly adjust your angle to keep it from moving around.
Bruce Hill
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bullojm1
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Post by bullojm1 »

Kenny,

You really need a regulator with a pressure gauge so you can dial in accurate pressures. Start with lower pressure (30 psi) and work yourself up. Here's a helpful table I used when I was building for pressures:


Image
Last edited by bullojm1 on Wed May 21, 2014 7:06 am, edited 2 times in total.
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kennyw
Class G
Posts: 19
Joined: Wed May 14, 2014 2:16 am
Location: KBVS

Post by kennyw »

bullojm1 wrote:Kenny,

You really need a regulator with a pressure gauge so you can dial in accurate pressures. Start with lower pressure (30 psi) and work yourself up. Here's a helpful table I used when I was building for pressures:
...
Thanks! Thats the info I was looking for. I kinda figured the tool pressure was too high. I just ordered 2 new air tool regulators from ATS.

paulie
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Joined: Tue Mar 20, 2012 8:15 pm

Rivet

Post by paulie »

It's a poor mechanic that blames his tools.
Sorry couldn't resist.
As I have said before in the aircraft industry we do not use regulators on our rivet guns and shop pressure is usually 90psi. It's all about technique and having a gun with a good throttle.
I've shot -4 rivets with a 4X gun. It is a quality gun though.

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