1/8" 470 Rivets - Tough to set!

Rupester · Post by **Rupester** » Sun Apr 02, 2006 11:37 pm

I'm having a devil of a time setting the 1/8" 470 rivets. They do NOT want to form a shop head when I try to buck 'em . I'm using an ATS 3X rivet gun with 80psi off the compressor, reduced at the gun. On some of the longer rivets (6's and 8's) I have to shoot for multiple minutes to get any "crush" on the rivets at all. (I have no problem with 3/32" ...they're a piece o' cake.) For whatever reason, the 1/8" rivets feel as hard as a rock ... nothing like the 3/32". Given the number of structural 1/8" rivets coming at me in wings and fuse, I need to solve this problem. Any ideas out there ??

Terry Ruprecht
9A Empennage
Mahomet, IL

jim_geo · Post by **jim_geo** » Mon Apr 03, 2006 12:58 am

What is the pressure at the gun?

tshort · Post by **tshort** » Mon Apr 03, 2006 3:34 am

Heavy enough bucking bar?

Thomas
-8 wings

captain_john · Post by **captain_john** » Mon Apr 03, 2006 5:52 am

With a 3X gun I use about 30-40 psi at the gun and as beefy a bucking bar as will fit in the space provided.

Aside from that, I don't know what else to say aside from helping you to do a few.

CJ

johnk · Post by **johnk** » Mon Apr 03, 2006 6:25 am

If you're really hitting them for multiple minutes then you're probably not hitting them hard enough and/or using a too-small bar. The 1/8 rivets require considerable force to set. Turn up the pressure, use a larger bar, and hold everything together firmly. The setting process should be complete within a few seconds. If you continue to pound the rivet for much longer, then the rivet becomes work hardened and will not set properly. To appreciate the force needed, try setting a couple of 1/8 rivets in some scrap using your C-frame and an ordinary hammer.

Post by **Spike** » Mon Apr 03, 2006 8:37 am

Im with CJ. 50 lbs at the gun, heavy bucking bar, and dont be afraid to put a bit 'O muscle on it to keep the gun sqaure on the head. Or, buy a pneumatic squeezah. Ive borrowed one from a friend and might have to buy one if he asks for it back. What a difference.

cjensen · Post by **cjensen** » Mon Apr 03, 2006 9:20 am

terry, when are you gonna work next? i'm happy to come over to see if i can lend a helping hand. i'm leaving thursday for SNF, be back sunday. but, anytime around there is fine. let me know.

Rupester · Post by **Rupester** » Mon Apr 03, 2006 11:16 am

Thanks for the suggestions. I'm using a good size bucking bar ... certainly not a small one, though I don't know the exact lbs. I may have to put a pressure gauge on the gun itself. I'm using the Vans-recommended swivel-regulator at the gun. My gauge off the compressor reads 85psi, as does the gauge at my filter-regulator-oiler station. Maybe some pressure drop between there and the gun? Doesn't seem probable ....it's only 25' of 3/8 i.d. hose. Oh well ... it may wait til after Sun n Fun, anyway.

Terry
N319TE - RV-9A

jim_geo · Post by **jim_geo** » Mon Apr 03, 2006 12:11 pm

You really need to see the pressure at the gun. Those flow limiters are unreliable for any kind of pressure regulation. Get a small regulator from Napa at least and use about 50 lbs at rest pressure (for 1/8' rivets). That'll drop to about 45 lbs as the tool is being used. Your rivets will be very happy you did.

tshort · Post by **tshort** » Mon Apr 03, 2006 12:50 pm

Rupester wrote:Maybe some pressure drop between there and the gun? Doesn't seem probable ....it's only 25' of 3/8 i.d. hose.

I've heard 1PSI per 10' of hose .... don't know how accurate that is... ?

Thomas
-8 wings

mkast · Post by **mkast** » Mon Apr 03, 2006 1:36 pm

I think to be safe... smash some rivets on a practice plate.

prestwich · Post by **prestwich** » Mon Apr 03, 2006 2:19 pm

Something funny is going on, that's for sure. Is it possible that you're using a die that's too big, and it's hitting the airplane part before it hits the rivet? I've only got about 10 rivets worth of hammer time, but I'm setting the -4s in about five seconds with a 2x gun at about 60psi.

Rupester · Post by **Rupester** » Mon Apr 03, 2006 4:53 pm

Negative on the "big die" idea. If it were hitting the work before the rivet, it would really be scarring up my aluminum. No sign of such. I've also tried 3 different AN470 rivet sets ... same result with all three. FYI ... when I can squeeze the 1/8" rivets, they're going fine.
Question: Do you guys regulate down the air pressure at the gun to slow down the frequency of the rivet impacts ? (That's what they said to do at the Sportair workshop.)

Terry

RV-9A
(HS done, VS nearly done)

Post by **Spike** » Tue Apr 04, 2006 6:31 am

Nope. I control the speed of the hits with the trigger.

-- John

bmurrish · Post by **bmurrish** » Tue Apr 04, 2006 7:04 am

I got the following off Dan Checkoway's site and it has been working well for me:

Suggested Operating Pressures
As I mentioned, I use different operating air pressures at the rivet gun for various different sizes of rivets and material. I put this table of information together based on my experience. Keep in mind that I use an Avery 3X rivet gun, and that your results may vary (some builders opt for a 2X gun, which may behave very differently). Also, you can vary the duration of driving the rivet to compensate for pressure in many cases. For example, instead of cranking the psi up, you can drive the rivet for a longer period of time. Anyway, here are the "baseline" settings I use for reference:
AN426 Rivets:

Rivet Type Air Pressure Duration
AN426AD3-3 to 3-4 34 psi 1 second
AN426AD3-4.5 to 3-5 37 psi 1 ½ seconds
AN426AD3-6 plus 40 psi 1 ½ seconds
AN426AD4-4 to 4-5 45 psi 1 second
AN426AD4-6 to 4-9 50 psi 1 ½ to 2 seconds

AN470 Rivets:

Rivet Type Air Pressure Duration
AN470AD4-4 to 4-5 60 psi 1 second
AN470AD4-6 to 4-7 60 psi 1 ½ seconds
AN470AD4-8 to 4-9 75 psi 1 ½ seconds
AN470AD4-9 plus 80 psi 1 ½ to 2 seconds

cjensen · Post by **cjensen** » Tue Apr 04, 2006 8:51 am

i use that exact same table. i have it printed out and tacked to my shop wall for reference. there may be some small adjustments needed here and there, but for the most part, it works.

prestwich · Post by **prestwich** » Fri Apr 14, 2006 12:07 am

One and a half seconds? How you gonna count that? Here's my new contraption -- an air valve operated by a built-in electric solenoid, connected to a timer that is triggered by a momentary switch mounted near the trigger - which is taped down - of the rivet gun.

As it's shown in the pic, the timer is adjustable 0 to 3 seconds, with 1/20 sec gradations. Tweaking one of the little screws on the bottom lets me select the dial range -- 0 to 1.2, 0 to 3, 0 to 12, or 0 to 30. Also, can select units of seconds, minutes, hours, or 10 hours. So it's a fractional second to multiple hour timer.

I keep the rivet gun trigger taped down, and now I just press the momentary switch with my thumb, and I get my 1.5 seconds (or whatever) of hammer action.

If I can figure out how to get the gun apart, I think I'll remove the trigger, bypass the air valve, and mount the switch in the trigger spot.

jim_geo · Post by **jim_geo** » Fri Apr 14, 2006 12:56 am

That is really something!

captain_john · Post by **captain_john** » Fri Apr 14, 2006 6:23 am

WOW! That is something!!!

We do have some very creative people on this board!

I do a one one thousand, two one thousand, three one thousand count and if the rivet isn't set in that time there is usually a reason. Sometimes it is bucking bar interference or the bar isn't totally engaged with the rivet.

Does the timer thing work for you? It really IS quite clever!

CJ

prestwich · Post by **prestwich** » Fri Apr 14, 2006 9:47 am

captain_john wrote:
Does the timer thing work for you?

CJ

I'll let you know after I try it! I've had the valve and timer for months, just got the switch in yesterday after playing with different switch styles and mounting options. But hammering in mid air, it works great.

I'm not big on holding things together with tape, but wanted to prove the theory before I spend time modifying the gun with a real switch mount of some sort.

I actually bought the valve and timer for another project months ago, but even then I planned to use them for this. The back-riveted rivets on my practice kit all came out different lengths,

, so I decided to substitute technology for innate craftsmanship.

I bucked a couple of rivets using a squeezer yoke as a bucking bar, but now have a bucking bar set on order. Once I get that and make a final desision on the "skin rivet order" question, I'll give this mad scientist beast a run and post some photo results back here.

RivetBangers.com

1/8" 470 Rivets - Tough to set!

1/8" 470 Rivets - Tough to set!

Riveting Air Pressures