Pneumatic ?C? Squeeze Question

[Badger1220]

I have just started a -8A slow build, and after using my hand squeeze for construction of the horizontal stab, I knew my hands were not strong enough to squeeze all the -4 rivets that will be forthcoming.

All that to say I purchased a single cylinder (214 Style) squeeze. The spec states the aluminum rivet capacity is 1/8?, but using it to put together the rudder skeleton, it worked fine setting the AN470AD4-5 and -6 rivets that fasten the 607PP and 608PP to the 802PP spar.

When I tried to set the AN470AD4-7 and -8 that fasten the 606PP to the spar, the squeeze it did nothing! I was running 80 psi so I increased the psi to 100 and then to 120 psi, still no movement. So, is the -5 and -6 rivets over its maximum limit or do I have a weak squeezer?

Any insight would be appreciated.

[Mike S]

Are you setting the unit up so the piston gets full travel??

Most of the force is generated toward the end of the travel.

[txaviator]

Exactly what Mike said! It almost looks funny when you set the dies, but the real torque does indeed happen at the end of the travel. So to simplify things, sometimes it may appear that you have the unit set to squeeze a real short rivet. When in fact, that's where it really needs to be in order to fully squeeze a longer rivet. Tough to explain, but the bottom line is that on longer rivets, don't be too overly concerned with the gap within the dies looking too shallow. Sometimes it is deceptive. Practice on some scrap and you'll see what we are talking about. It is most likely NOT the pneumatic squeezer. This question has come up a bunch over the years, myself included, back when I started using one! When there is a big gap between the dies- such as the gap you'd 'think' you need for the longer rivets, nothing is going to happen. It simply doesn't have much torque at that travel range. And PSI on the compressor won't help it either. It's ALL in the gap between the dies.

[sahrens]

Avery Tools sells an adjustable set holder for pneumatic squeezers.

http://www.averytools.com/prodinfo.asp?number=274

I bought one for mine. It makes the adjustment for different rivet lengths much easier.

If you sloooowly activate your squeezer like your are going to set a rivet, you can measure how the dies are set. Do NOT slam it to the stop, just let it slowly extended. You can gauge if it is close to setting the rivet to the proper length by holding a rivet next to the space between the dies. I hope that makes sense.

If you try to set the rivet and it is not set to the correct length, adjust the set holder and reset the rivet. With a squeezer you can set the rivet a few times. Of course, the rivet will start to harden so more than just a four or five attempts would not be good. You should be able to finish in no more than three attempts.

As others have stated, practice on some scrap. Ten or twenty rivets are nothing. They are sold by the pound.