1919 A4 Forums banner

1 - 4 of 4 Posts

·
Registered
Joined
·
926 Posts
Discussion Starter #1
What is the difference between the two? I know you have to remove more metal from the side plate when countersinking? Is that what makes it weaker or are the rivets themselves weaker? Since Black Bear won't be providing anymore till november is there any substitute for em in the meantime? would 90 degree rivets be fine with a crank fire adapter?
thanks for any info
 

·
Premium Member
Joined
·
2,587 Posts
60 deg. is an old standard (after all, Browning used them in the early 20th century). Much of the rest of the world has moved on to 83, 90 and 100 deg. depending on application. The most common commercial rivet available today is 90 deg. which is why most of the large builders use them. BlackBear uses 60 deg. like the originals, but he has these custom made. I don't understand the hype about Mil-spec. Face it, any current ANSI, ISO, BS, or SAE spec. for solid steel rivets will be tougher than a WW-II (much less a WW-I) military specification. Mil-spec is going away, the military finally figured out they were paying more for materials that were inferior to commercial specs.

There was a thread a week or two ago from AA (?) selling 90 deg. sets. Also, both me and someone else are trying to put together 60 deg. sets to sell, but we're both over a month away. OOW also has 90 deg. sets.

Hope this helps...

MSG

Here's a link to the AA post:

http://www.1919a4.com/forums/showthread.php?t=1487&highlight=rivets
 

·
Premium Member
Joined
·
6,504 Posts
About 30 degrees :).

It makes no difference...the shear strength is in the diameter not the head angle and whether they are 60 or 90 degree makes no difference...they ain't pulling out of there or shearing off. Use the proper angle countersink for the rivet, but truth is, you can even use a 60 degree countersink with 90 degree rivets and these things are so soft, by the time you pound them with an air hammer they're gonna fill in and tighten up just fine. You can make rivets out of Home Depot rod stock if you want.

Before that sideplate could move to shear eleven 3/16" rivets you'd have to take out those two big 11/32" bad boys first...it ain't happenin'. The shear strength of each 3/16" rivet is about 540 pounds so the cumulative shear strength just for the small rivets is 5940 pounds...you could hoist my 4x4 Tahoe with those.

Your backplate only has about 1.875 square inches of engagement area and the aggregate sum of the rivet cross sectional shear area is 2.74 square inches...your backplate would tear out of it's slots long before you ever saw a rivet shear; and if that much catastrophic damage happened you probably wouldn't be around to worry about it anyway :).

Happy riveting.
 

·
Registered
Joined
·
23 Posts
The only real physical difference is the angle of the rivet head. That angle makes some difference in the fit and strength of the rivet in holding it in place. Besides being the old standard for use in BMG's, the 60 degree rivet is the current standard used for USGI M2 & M3 .50BMG machine guns. Many commercial vendors have substituted the 90 degree rivets for use with M1919type .30BMG's due to being easily obtainable and affordable. The 90 degree rivet works well applied to .30BMG' s due to the strength required versus the operating pressures. Not sure such a substitute should be applied to use with .50BMG's, but I tend to err on the side of caution. Applying 90 degree rivets also requires countersinking the 60 degree rivet holes already on the plates to 90 degree which removes more material from a toleranced dimension on the sideplate.
60 degree rivets have been harder to come by and more expensive, but that is all about to change soon with new production.
 
1 - 4 of 4 Posts
Top