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Does It Matter Which Side the Shop Head Is On?

C

Chris flies

Member
Shop head - machine head

What is the proper head to put on the aft HZ stab. Most seem to have the machine head on the aft side.
 
In general, it is a good idea to put the shop head on the side with the thicker material. In practice, sometimes you just have to do what works due to accesability, or ease of removal if you buggrit up.
 
And another point to help out a Newbee

The proper nomenclature is

Shop head - the one you put on in the shop
and
Manufactured head - the one put on during manufacture
 
I don't think it matters - I put the manufactured head on the outside as it will be easier to paint.

Pete
 
Pirkka said:
Just curious, what rule?

From [SIZE=-1]MIL-R-46196A:[/SIZE]"3.3.3.1 Head direction. Unless specified on the engineering drawing or specification, the manufactured head of the rivet shall be located on exterior surfaces." That sounds like a rule to me...

http://www.auf.asn.au/scratchbuilder/MIL-R-47196A.pdf
Click to expand...

Those Aussies always seem to have a document for everything.

I noticed the following:

"3.3.3.4 Head diameter.
Driven universal heads may be formed on the shank side of the rivet using the next smaller size
universal type head riveting die (example, 1/8 inch die for 5/32 inch shop head rivet). Driven universal type head sizes shall conform to
the respective rivet diameter shown on , unless otherwise specified on the engineering drawing or specification."

I think this is the answer to a question I asked an AME several years ago... "can you use a universal rivet set to back rivet?" Apparently, it's allowed.

V
 
I think Van's instructions addressed the issue, suggesting there's nothing to indicate that it makes much difference.

I tend to follow the non-rule rule and place it on the thinner material. But I ignore it completely if it makes shooting the rivet problematic (I HATE using offset sets!), or if if it makes access to the manufactured head easier in the event I need to drill it out.
 
G'day guys,

I'm about to rivet HS on my -8 together ... and have a "wombat" question. When riveting the HS-609PP's to the HS-603PP ... which side should the shop head be on?

I've looked at numerous builders sights and i've seen the rivet point both directions ... but which is the correct one?

Many thank,

Matt
 
AussieRV said:
G'day guys,

I'm about to rivet HS on my -8 together ... and have a "wombat" question. When riveting the HS-609PP's to the HS-603PP ... which side should the shop head be on?

I've looked at numerous builders sights and i've seen the rivet point both directions ... but which is the correct one?

Many thank,

Matt
Click to expand...

Common practice is to have the factory head against the thinner material, but there are more important considerations, such as:

-access for bucking or driving the rivet
-the ability to drill out rivets
-ease of inspection
-appearance

In my opinion, access for drilling out rivets is the most important. Not just because a rivet may be bad, but because you may wish to de-rivet an assembly later on.

V
 
Vern is entirely correct. There is another consideration, clearance for other assemblies, but that is usually specified in the plans. If flush rivets, pay attention to which side the flush head goes on (I'm not talking skin rivets, I'm talking about rivets used to allow to assemblies to mate flat). Sometimes even the universal head is important because it's height is consistent and usually thinner than the shop head, so read ahead and see what else may go nearby. But if the plans don't specify, then follow the common practices and you won't go wrong.
 
Van's Plans are very good at showing you the orientation of the rivets for each assembly. The basic rule is that the shop head should point Inside, Down or Aft. Vans has a lot of exceptions to this rule.
 
Rivet Removal?

One more thing to consider. If I screw it up, from which side can I drill the shop head the easiest?

Alan Jackson
Hartselle, Alabama
 
Hey Folks,

I just riveted together my rear spar for the HS. I riveted the 609PP and 603PP parts together. For ease of assembly (I used my squeezer) I put the factory heads on the 603PP side, hence the shop head would be on the 609PP side. After looking at some pics from other builders, everyone else did it the other way. Am I now going to have to drill out all those rivets and replace them the other way?

Thanks

Chris
 
Absolutely NOT!

No hard rule on this. If all else is equal, most people prefer to have the shop head on the side of the thicker material. This creates less distortion. But there is no set rule. Certainly not enough to drill out perfectly good rivets.
 
Last edited:
I agree with Mel.

In general I try to put mine on the thicker material, but I also think about the need for a possible disassembly effort in the future. If I need to drill rivets for some unknown reason in the future, I like having the manufactured head facing me so I know where absolute center is to drill the rivet. This way my chances of enlarging holes goes way down in the future.
 
Thanks Mel and Phil!

I built my VS first. During the construction of the spar, for that, Vans has you put the factory head on the side with the thin metal, so shop head on thick metal side. They mentioned that typically the factory head goes on the thick metal side. I just wanted to make sure there was no hard rule on this.

Chris
 
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