Fastest way to remove revits 3

[bicolexpress]

Hi everybody!

I need help/sugestions on the fastest way to remove rivets from old/aged railroad bridges without damaging members connected by them. We have to do this in more than
50 bridges so I'm looking for the fastest way to do it.

Thanks in advance...

 

[metengr]

Since you are in the field performing this operation I would either drill them out or grind the rivet heads off and use a portable hydraulic jack to drive the rivet shank out. I thought about EDM (electrical discharge machining), which is very effective in metal removal, but you would need electrical service in the field - possibly a portable gas fired generator.

Remember, don't remove all of the rivets while standing under the bridge.

 

[MikeHalloran]

I suggest getting electrical power to the sites so you can use a magnetically attached drill press with power feed to drill the rivets out.




Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA

 

[Kapitan]

As this is being done on site and there are probably a large number or rivets to be removed I would burn the heads off with an Oxy-Acetylene torch. The rivets are bound to be at least 1/2 " dia, more like 3/4 " or 1" as they are in railway bridges, so the heads will present quite a lot of metal to be removed.

Some of these rivets will not always be in a position where a grinding wheel could get to them and would not be as quick to get the heads off. A cutting torch nozzle can get in where a grinding wheel never will.

Using the cutter nozzle on its side the head can be 'shaved' away until all the head has gone and then the rivet shank driven out with a punch and hammer or jack.

To try and drill them out would be difficult as finding the centre of the original drilled hole would be pot luck and the result will be a hole that is certainly not circular. Also just trying to manhandle a drill capable of drilling out say a 3/4 " diameter rivet is very heavy. It could well be that this has to be done overhead or any other awkward angle.

An oxy-acetylene cutter is very manouverable and much lighter to use. A skilled boilermaker or welder could do this without doing any local damage to the bridge members.

 

[JStephen]

Arc gouge might be another option.

Is this specific rivets, or are you replacing ALL the rivets on these bridges???

 

[scooter911]

I'd go with Kapitan's suggestion, they make a curved torch tip specifically designed for this application, check you local welding supply. If you do go with the electric drill, you could use an end mill to remove the head. I think you might end up using a combination of methods.

Scooter

 

[unclesyd]

As stated by Kapitan & scooter911 they make special tips called rivet cutting or rivet washing for removal of rivets. These are low velocity O2 not the normal high velocity O2 cutting tips.

http://www.harriscal.it/PR SPECIAL tip EN.htm

If you have to punch to shank out they are rivet punches made for knocking out the shanks. We made ours from S-7 tool steel.

 

[Kapitan]

I've just found this by seaching Googling " rivet removal " ,

http://www.aisc.org/MSCTemplate.cfm...tomSource/Faq/SteelInterchange.cfm&FaqID=1924

Its about rivet removal in bridges...

 

[bicolexpress]

Hello Guys!

First of all I would like to thank you all for the suggestions (special mention to Kapitan). Our current
process is the flame cutting of the rivet's head and hammering the shunk out. However, with this process, we have difficulty in hammering out the shunks because the rivets were already fused into the members (base metal)
maybe due to the span of time that they were connected.
Anyway we will consider all your suggestions to come up with the fastest process to ease up our operations.

Again, thank you very much!

 

[MikeHalloran]

You've got, what, a million rivets to replace? More? The Smoke Wrench and Gorilla method is going to use up a lot of oxygen, and suffer a lot of injuries, and when the gorillas start getting tired, damage some bridge parts.

You need to develop a mass production technique.

WRT getting the shanks out, go back to the site linke by Kapitan, and take special note of the references to 'coring'. That's why I suggested drilling; you've got a better chance of locating the center of the shank, and drilling out most of the shank without damage to the connected members, while the head is still on the rivet.

I suggest a crew as follows:

- Specialist 1, locating the center of the rivet heads, e.g. using a drill bushing with a female conical locator on a spot drill bit, driven by a cordless hand drill.

- Specialist 2, placing a lightweight hydraulically driven magnetically attached drill press, and drilling out the majority of the shank and much of the head. He might be instructed to drill deep enough to get into the upset end, but not through it, so he leaves a blind hole in a severely weakened shank.

- Specialist 3, using a pneumatic hammer and chisel to remove the periphery of the head.

- Specialist 4, using a pneumatic hammer with a drift point smaller than the blind hole left by S.2, to drive the shank out.

- Specialist 3a, to catch the rivet heads.

- Specialist 4a, to catch the rivet shanks.

- Specialist 5, to refuel the generator and the compressor, and keep all the hoses and wires untangled and out of harms way.

Plus, of course, more people to ream the holes, place the bolts, spin the nuts down, and torque the nuts.



Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA

 

[pennpoint]

MikeHalloran
Very well thought out Mike. I gave you a star.
But you have too many specialist's.
Maybe some of them could just be helpers. One has to start some where, right?

 

[MikeHalloran]

These days, everyone's a specialist.

I figured if each guy drives one tool, he's inclined to take better care of it.

If everybody uses every tool, they squabble about who is responsible for them, nobody takes care of them, and they don't last long.





Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA

 

[swall]

bicolexpress--I was just curious as to why the rivets have to be removed. Has NDT detected flaws or is it just some sort of safety requirement for periodic removal/replacement?

 

[adrianviorel]

Dear Mike,
where are the specialists that should support the bridge while rivets are removed? I suggest a train at each end of the bridge.

 

[unclesyd]

Support isn't a problem if you removed 1 less than the actual number required to hold the bridge up.

bicolexpress,
I just talked to a old gentleman, 90's, that was a burner foreman in a shipyard and he said the only way to remove a number of rivets was by torch. He stated that the older rivets made from dead soft iron were easily remove by pneumatic chisel and punch but still most were torched. He stated that the later model rivets, higher carbon steel were a bear in the 7/8" and 1" both to set and remove. I mentioned the type torch and he said that he hadn't seen the company name of the one he used for years. He said that a good torch man could keep several people busy. It take two tips, one to cut the head and another to groove the shank.