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Demolition puzzle - removed rivet feature

Demolition puzzle - removed rivet feature

(OP)
Curious - What is the explanation for the flat area on the removal side of what I believe is a standard bridge rivet? What removal methods would have been used? I can see the torch mark, but how was the head removed? Did the head removal method leave the flat area?










RE: Demolition puzzle - removed rivet feature

The head of the rivet was torched off and the rivet was the pounded out with a pin and hammer. The flat is from the pin that was used.

RE: Demolition puzzle - removed rivet feature

(OP)
So, a 3/4" pin or so driven against the torched surface under the head flattened it smooth?

RE: Demolition puzzle - removed rivet feature

Yes. The thin flashing around part of the cut end is the result of very hot material which was previously probably part of the head being molded between the rivet bore and the pin used to drive it out as the rivet was removed.

RE: Demolition puzzle - removed rivet feature

Rivets are driven hot, so they completely fill the hole even if the hole is slightly offset between the connecting plates. To remove them takes considerable effort. The rivet head is removed with a oxy-fuel torch and as can be seen in a couple of the photos, the shank of the rivet is pierced with the torch. Then the rivet is typically driven out using a 35 pound pneumatic rivet gun. The "hammer blows" are numerous and rapid, thus the end being driven is flattened by the rivet gun.

I hate to recollect how many rivets I've driven out while renovating bridges in need of repair.

Best regards - Al

RE: Demolition puzzle - removed rivet feature

One of the tools used by ironworkers is the pneumatic rivet buster which shears off the rivet heads.

RE: Demolition puzzle - removed rivet feature

Examining the end of the picture rivet where the head was removed, I don't believe that the head was flame cut as there should be globules or traces of melted iron showing. I think that it was sheared off with a rivet buster and then pried off as shown by the excess flashing.

RE: Demolition puzzle - removed rivet feature

The end of the rivet was very clearly pierced with a torch. Any splatter or anything soft was flattened into the shank as the rivet was pressed out.

RE: Demolition puzzle - removed rivet feature

I tend to agree with chicopee that the head was most likely busted off. Burning the head off is less physically strenuous but a helldog is faster and doesn't require as much care (30+ years ago I worked for an old-time who would say "I don't trust ironworkers with torches"). The only times I've seen ironworkers use a torch was when the clearance was tight. If the chisel has too much angle the head won't come off and the base metal will be damaged.

This was an interesting rivet removal. After taking off the head, they had a hard time punching it out so they used an air-arc rod to try to loosen it. And, it worked (once in a while you can trust them with fire.)

RE: Demolition puzzle - removed rivet feature

another view. The edge is polished because I just ground the burrs off.

RE: Demolition puzzle - removed rivet feature

This is where they put the rod in. I know what it looks like but it's Sunday let's keep it clean.angel

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