'Nother Question from the garage...

SteelMike · #1 08-09-2008, 09:58 PM

'Nother quick question from the garage:

If, when you use a rivet gauge for the shop head height (not diameter), and you can just barely get the gauge to start to go across the rivet, but it won't go all the way across, is the shop head tall enough?

If it's not, I'm going to have to go up to 4-8's, and I don't have any 4-8's, and it's going to be a PITA to get some tomorrow...

Input appreciated!

Thanks...

danielhv · #2 08-09-2008, 10:35 PM

Quote:

Originally Posted by SteelMike

'Nother quick question from the garage:

If, when you use a rivet gauge for the shop head height (not diameter), and you can just barely get the gauge to start to go across the rivet, but it won't go all the way across, is the shop head tall enough?

If it's not, I'm going to have to go up to 4-8's, and I don't have any 4-8's, and it's going to be a PITA to get some tomorrow...

Input appreciated!

Thanks...

From my understanding.... the shop head should just barely NOT fit in the round hole on one end of the gauge, and should pass through the notch at the other end without hitting the top part of the gauge.... so if the gauge looks like this: n then the shop head should not hit the top of the n

If that makes sense...

Another way is to just measure using your metal ruler in 32nds or 64ths, or better yet, a caliper. You can measure the shop head diameter and height.

SteelMike · #3 08-09-2008, 11:31 PM

Uhh.. Whoa, I just about had a heart attack, because the way you described it, every single one of my rivets would be out of tolerance, but I think we're having a misunderstanding. I have gauges like the ones below that have a minimum diameter hole, and a minimum height notch. My 4-7 rivets are scraping the top of the minimum height notch and I'm wondering if I need to go to 4-8s (which I don't have, hence the thread).

danielhv · #4 08-09-2008, 11:49 PM

Quote:

Originally Posted by SteelMike

Uhh.. Whoa, I just about had a heart attack, because the way you described it, every single one of my rivets would be out of tolerance, but I think we're having a misunderstanding. I have gauges like the ones below that have a minimum diameter hole, and a minimum height notch. My 4-7 rivets are scraping the top of the minimum height notch and I'm wondering if I need to go to 4-8s (which I don't have, hence the thread).

Those are the same ones I have... Ok, if your 4-7's are scraping the TOP of the notch, then they are too tall... you can try squeezing them a tad bit more. Using a longer rivet will sit even taller than the -7... btw, where are these rivets going? I dont recall using any other rivets besides whats called for in the plans on the tail feathers...

Not sure if we're on the same page as far as the problem.....

SteelMike · #5 08-09-2008, 11:49 PM

I think I found my answer - check out this article that I just dug up from the vaults. Very interesting... and comforting.

http://www.kilohotel.com/rv8/rvlinks/marvelrivets.html

danielhv · #6 08-09-2008, 11:56 PM

When in doubt... measure it out!

The "shop" head of the rivet should be 1.5 times the original diameter of the rivet and the height should be 0.5 times original diameter.

SteelMike · #7 08-10-2008, 12:04 AM

Time out.

The notches on the bottom of those gauges are minimum height notches, not maximum height notches (i.e. your rivet must not fit under the notch).

... right? It sounds like one of us is going to be veeeery unhappy about this, and I'm about 99% confident. Maybe I'll win that bet after all...

SteelMike · #8 08-10-2008, 12:07 AM

Here's the verbiage from the part listing for those gauges (I just pulled it from the first one google gave me):

Shop Head Rivet Gauge Set: Set of four gauges for -3, -4, -5, & -6 rivets. Each gauge measures MINIMUM height and MINIMUM diameter of shop heads AFTER settingEliminates guessing if your rivets are properly set. Works for measuring both universal head and flush rivets. Precision machined to size from 2024 aluminum. Rivet size permanently stamped on each gauge. Color coded anodized finish. Made in USA by Avery Enterprises.

http://www.skygeek.com/ats-ae1007.html

rv9builder · #9 08-10-2008, 12:29 AM

Mike,

Relax, you're using the gauge correctly. If the rivet is properly set, the shop head won't fit through the hole and it won't fit under the notch.

sprucemoose · #10 08-10-2008, 12:45 AM

Those little gauges, while handy, have been responsible for many thousands of perfectly acceptable rivets being drilled out. What you really need is a dial caliper and an understanding of the required dimensions of a driven rivet. The 1.5X and .5X are good rules of thumb but they are a bit overly conservative.

The whole tale can be read in the Mil-spec on driven rivets:

http://www.vansaircraft.com/public/Specs.htm

With time and experience, you'll be able to tell by sight, and won't need any sort of gauge.