[TheForge] stubborn rivets

[jerry Frost]

Bingo Mike. No, heating the spring will NOT expand the hole making the rivet
drop out. As Mike says the hole will shrink, this only works on rings say a
nut on a bolt type situation. In the center of plate like a leaf spring it's
a no go.

Stop looking for some new way to do this, getting old rivets out is old
school shop class stuff. got a copy of one of the old shop manuals? The
Engineering handbook has a how to section IIRC. There are a bunch online now
the Brits uploaded the Rural I can't recall the rest but it's like the
Mother Earth News thought it was. A whole series of low tech ways to make
and do things old school and improvised. "The Complete Modern Blacksmith" by
Alexander Weygers covers rivets using them and removing them.

Following is how I do it.

First try. Cut the SET head (as opposed to the PEENED head) off with a
chisel and drive it out with a pin punch a straight shanked flat ended punch
for driving: roll pins, pins and rivets out. If it won't drive out with a
couple firm sharp blows do NOT continue driving on it or you'll make it
worse. Go to method 2

Try 2, Warm the leaf stack to under 400f, makes a drop of oil smoke and
squirt some 3 in 1 oil on the rivet, ATF works a treat it has rust
inhibiters and converters in the formula. As the steel cools it will draw
the oil into the joint by capilarity. The heating and cooling cycle will
have crushed the rust and loosened it try driving it out again. Just a
couple sharp raps with a moderate size hammer, you don't want to forge the
rivet into a permanent join.

If #2 fails get it hotter and repeat but use water to cool it this time.
Water made the rust, water will dissolve it and break it loose, it's not my
favorite or it'd be #2 on my list. Same process as #2 but use water. If you
have water soluble oil say band saw or drill press water bath cutting oil
that's even better. No, don't go out and buy a can for this just use it if
you have some it helps it's NOT a magic bullet. A couple sharp raps on the
punch if it doesn't break free it's time to get out the drill and bits.

Frosty

-----Original Message-----
From: TheForge [mailto:theforge-bounces at mailman.qth.net] On Behalf Of Mike
Spencer
Sent: Tuesday, August 9, 2016 10:44 AM
To: theforge at mailman.qth.net
Subject: [TheForge] Re: stubborn rivets


> my 2nd least desired solution is to use a welding tip on the torch and 
> heat the surround metal to allow the rivet body to fall out.
>
> Option #2 would have been my first choice .

Not sure that would work as you think.  If you heat a ring, it gets bigger
in diameter beause the ring material gets longer linearly.

But if you heat a small region of the truck frame around the rivet hole,
it's surrounded and constrained by cold metal so I think the hole would get
smaller, thus tighter.  That could be good because after cooling, the hole
might be a tiny bit enlarged from crushing.
But it will be hard to heat uniformly all around the rivet, expecially if,
as I imagine, the mating flange of the bracket is hard up against the frame.

I haven't used oxy-propane but if you have a welding tip that can quickly
heat the rivet itself to red heat, the rivet will try to expand but will be
restrained by the surrounding cold(er) hole. As the rivet gets to (even
dull) red heat, the force or the constraining hole will crush the rivet a
tiny amount, making it smaller.  It will also crush any oxide between the
rivet and the hole and, as rust isn't malleable at a dull red heat, it wil
tend to crumble and loosen.

> suggestions welcomed.

That, FWIW, is mine.  Good luck.


- Mike

-- 
Michael Spencer                  Nova Scotia, Canada       .~. 
                                                           /V\ 
mspencer at tallships.ca                                     /( )\
http://home.tallships.ca/mspencer/                        ^^-^^
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