SteelMike

SteelMike

Well Known Member
'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...
 
SteelMike said:
'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...
Click to expand...

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... :D

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.
 
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).

stylespilotshop_2011_3466879
 
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SteelMike said:
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).

stylespilotshop_2011_3466879
Click to expand...

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.....
 
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.
 
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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...
 
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
 
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.
 
Throw those gauges away!

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.
 
SteelMike said:
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...
Click to expand...

Don't forget that you need to be measuring the height of the shop head only, NOT the head and the raised dimple together when you are working with flush rivets.Those gauges with the "feet" don't really work here, except to use the hole in the gauge to check the shop head diameter.
 
Okay, phew, I'm not going crazy.

Daniel - please tell me we're having a misunderstanding and that you have some other type of gauges or something, right?

For my original question, I'll just try to measure the height with my scale.
 
SteelMike said:
Okay, phew, I'm not going crazy.

Daniel - please tell me we're having a misunderstanding and that you have some other type of gauges or something, right?

For my original question, I'll just try to measure the height with my scale.
Click to expand...

Guess I'll have to rebuild my entire tail section.... NOT!!! :D Thought you had me there didn't ya Mike? I have gotten used to measuring driven rivets with a caliper... Mine is a digital one, not dial... but still works well. The only time you can use the gauges is on standard rivets, which there aren't many so far... most are flush, which makes it almost impossible to check height accurately with the gauges that came in the tool kit. I use them typically when working on the spar, but here is my issue with them... When I set a rivet so that it meets the minimum diameter hole, it will not fit through the forks on the height gauge. So I've just quit using them. :rolleyes:
 
rv9builder said:
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.
Click to expand...

I can't say that Mike has it right, but he is close. The Avery gauges have the hole drilled at exactly 1.5x rivet diameter, and the notch cut at exactly .5x rivet diameter. A PERFECT shop head would just fit into the hole with no clearance, and the notch would just brush the shop head while the feet would be brushing the riveted piece, assuming there was no dimple height involved. This all assumes that the rivet started out at EXACTLY 1.5x diameter in length when it was selected for the pieces to be riveted. The suggestion to throw the gauges out may be a bit much here, but these gauges are obviously not the determining factor here. Carefully measure a few set rivet head diameters and heights to train your eye as to what looks right, and then work from there. There's "over/under" wiggle room in the specs for head diameters and heights, and you will quickly learn what is an acceptable rivet by eye alone.
 
Yeah - I noticed the same thing: if the shop head's diameter is big enough to not go through the diameter hole, then it won't fit width-wise through the "height" notch. Kind of a dumb system, if you ask me. I ground out one of notches so that it will measure the height.

Thanks for the clarification, Ron.
 
Now I'm not sure what's clear and what isn't. Could you post a couple of pics of the modified gauge, and a couple of rivets being "gauged"?
 
SteelMike said:
Yeah - I noticed the same thing: if the shop head's diameter is big enough to not go through the diameter hole, then it won't fit width-wise through the "height" notch. Kind of a dumb system, if you ask me. I ground out one of notches so that it will measure the height.

Thanks for the clarification, Ron.
Click to expand...

Mike, check PM's
 
Oh, and all for not, by the way. I was shocked to find someone locally with some 4-7.5 rivets, although they didn't have 4-8, but 4-7.5 should do it.
 
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