Structural Rivet Removal

[bjl]

A specification calls for the removal of structural rivets with out using pneumatic rivet breakers. In fact the proceedure is specified as follows: Using a rivet scarfing tip on a cutting torch remove all but 2mm of the head material then grind the remaining portion of the rivet head flush with the base metal. The rivet shank shall be removed by drilling.
Due to problems with the base metal I cannot allow the use of "hell dogs".
If I go ahead and impliment this spec how long can I expect it to take to remove one rivet in 3 and 4 ply material.

 

[evelrod]

It depends largely on the size of the rivit. I have removed a few over the years by the method you describe and it is truly a PITA! For most rivits I just cut the head off and blow a hole through the middle and knock them out with a 'bullpin' or a small pneumatic tool. Not too hard to learn and fairly fast. Just need someone who knows which end of the torch to light, that's all.

Rod

PS---I haven't seen, let alone used, a "helldog" since 1961.

 

[MikeMilburn]

Agree with Rod, although I haven't don't much rivet removal in structural members I've done my share in truck frames. If you're moderately good with a torch you can wash off the head and poke a hole thru the center of the rivet and, as Rod said, hammer the rivet out.
We have a torch here, not quite sure of the name,(tool rooms closed) but basically you need oxygen, a 12v battery and a good set of leathers. In simple terms you strike an arc with the rod which starts it burning when you turn on the oxygen. After you have it ignited you put the end of the rod against the pin, rivet or what ever you're wanting to remove and blow a hole thru the center. We use it here to blow out king pins, cylinder pins etc. If you're interested post back and I'll get the name...Mike

 

[sbc]

'sounds like a gouging rig?

 

[MikeMilburn]

It's called an Exothermic torch, couldn't find the brand we've got but this gets the point across,

http://www.brocoinc.com/military/pcmil60.html

it's a slick rig...Mike

 

[JAE]

Hey.....what's a "helldog".??? Just curious.

 

[evelrod]

It's a pneumatic chisel. Just GREAT BIG HEAVY OLD FASHIONED POS! Very akin to a slow cycling, very hard hitting 'jack hammer'.
The snap was usually chisel or shovel shaped but you had a 'spoon' snap you could use as well. It was capable of cutting the heads off structural rivets of just about ANY size. With care and practice it was effective and fast (and VERY loud). You still had to 'blow' through the rivet to knock it out. Rivets upset in the joint and cannot easily be driven out without damaging the holes unless that center is perforated, even a small hole works. A small rivet gun like a "90" or 80XX will work but a hammer and drift will work in a pinch.


Rod

 

[TheBlacksmith]

Thank you JAE and Rod. I was curious too but too dumb to ask!

Blacksmith

 

[bridgebuster]

Evelrod,

We still use helldogs in New York City. For what it's worth, NYSDOT spec's prohibit burning off rivet heads.

 

[pituitaryradio]

I've been "helldogging" on the Triboro Bridge for weeks. It is rough on the ol' carpal tunnel.

 

[deanc]

Go to

http://www.nationalboard.org

and look at the Winter 2003 Bulletin,esp. the references for the Boiler Rivets story.

At least 2 of them turn up on a "Google" search.