What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Setting adjustable set holder - pneumatic squeezer

DaX

DaX

Well Known Member
Does anyone know a way to properly set the adjustable set holder on a pneumatic squeezer the first time without having to squeeze test rivets?

I've been trying math formulas that just don't seem to work. I'm measuring the gap in the squeezer with calipers. I know that 1/4 turn of the set holder is equal to about 0.010". I've been trying (grip length) + (1/2 rivet diameter) as my setting, but this doesn't squeeze the rivet enough. I have been practicing on 0.032" sheet, so my grip length is 0.064". I'm using AN470AD4-4 rivets, so my (1/2 diameter) = 0.063". I would assume setting the squeezer to about 0.125" would be what I want, but I found that these rivets turn out not squeezed enough at 0.125" and they turn out great at 0.100".
 
DaX said:
Does anyone know a way to properly set the adjustable set holder on a pneumatic squeezer the first time without having to squeeze test rivets?

I've been trying math formulas that just don't seem to work. I'm measuring the gap in the squeezer with calipers. I know that 1/4 turn of the set holder is equal to about 0.010". I've been trying (grip length) + (1/2 rivet diameter) as my setting, but this doesn't squeeze the rivet enough. I have been practicing on 0.032" sheet, so my grip length is 0.064". I'm using AN470AD4-4 rivets, so my (1/2 diameter) = 0.063". I would assume setting the squeezer to about 0.125" would be what I want, but I found that these rivets turn out not squeezed enough at 0.125" and they turn out great at 0.100".
Click to expand...
See "Pneumatic rivet squeezer " just a few threads down on this page. Formulas are fine, but you can expect variations in results when you consider thicknesses of materials being riveted, flexing of yokes, air pressure, etc.
 
One issue is the yoke bends a little. you have to overset, to compensate for the yoke give.

I think I did away with measuring and all that after the first few hours. All the brain cycles weren't worth the results.

My rule of thumb, which has worked out well up to my Fuselage, is take the rivet length and divide it by 2, using a ruler on a table. Then back it off slightly.

I set a rivet, then it usually requires another quarter to a full turn. Set again, and i am usually good to go for that sized rivet.

Jae
 
By eye...

I just hold a rivet up to the gap between the dies, while fully extended (i.e. at end of the full stroke), and have gotten relatively good at getting close. I rarely have to "tweak" it more than once or twice after that, and it doesn't take much time (likely less than getting out a ruler or figuring formulas). You do have to develop the tendency to under-set with the first shot rather than over-set though...
 
Here's the easy and accurate way:

Start by setting wide, then close it up a turn at a time until the rivet meets specs. Then turn the set holder until the set is tight against the yoke, counting the number of turns. Write down the number of turns where you keep that size rivet. Whenever you use that size rivet again, run the set holder up until the set is tight against the yoke, then back off your specified number of turns. For example, the -3.5 rivets require 2 turns, and the -4's require 2.5 turns. Comes out right every time for me.

I do check the first rivet I squeeze, just to make sure, but they are always right, even if there is a slight difference in the metal thicknesses. Probably a tolerance thing.
 
Two things:
1) you must have 90PSI going to it, I have often left it on 45PSI after I use my gun.
2) watch that it doesnt unwind itself as mine does after setting a few rivet.
 
In my notes...

Hi Matt,

This is what I've written on my board and has been working pretty well for me.

I generally lower the air pressure to something like 20 psi, fully extend the plunger, unscrew the set holder till it contacts the opposite rivet set, then screw the set holder back in the required number of "1/2 turns", release the plunger, then adjust pressure accordingly. See the notes below.

Code: 
 Rivet
Length    "1/2" Turns
~~~~~~     ~~~~~~~~~~
  3.5         4
   4          4
   5          7
   6          10
   7          13
   8          15
- I fine tune from these values as necessary with a 1/2 turn here and there.
- I use the 'Avery' adjustable set holder which looks to have 24 threads/inch which comes out to about .042"/turn, or ~1/8" per 3 turns making it easy to adjust for "odd" sizes.
- The adjustable set holder has machined flats which makes it easy to count "1/2" turns.
- This is based upon a 3" yoke
- For the 2.5" yoke, I subtract one "1/2" turn due to the shorter lever arm.
- For the 4" yoke, I add one "1/2" turn for the longer lever arm.
- I've found that the above settings work pretty well for both AN470-4 and AN426-4.

Of course, YMMV. I'd advise that you verify the above on test samples and fine tune them as necessary. ;)

Regards,
/\/elson
Austin, TX
7A - Fuse (building the seats)
 
You must log in or register to reply here.
Back
Top