Lap seam, riveted boilers

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John Landrum
Posts: 31
Joined: Fri Feb 17, 2017 2:05 am

Lap seam, riveted boilers

Post by John Landrum »

I have one of the above lap seam, riveted boilers on an engine I am restoring. My question is, how to check the structural integrity of the rivets to know whether or not they are solid inside their holes or look like an hour glass and are just waiting the opportunity to become a high speed projectile when the boiler is put under steam pressure. Any thoughts?
Marty_Knox
Posts: 1723
Joined: Thu Jan 09, 2003 6:50 pm
Location: Michigan, USA

Re: Lap seam, riveted boilers

Post by Marty_Knox »

I would be more concerned about the lap seam itself. You can use dye penetrant to check for cracking.
Soot n' Cinders
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Joined: Wed Jun 27, 2012 5:24 pm
Location: Marietta, Georgia

Re: Lap seam, riveted boilers

Post by Soot n' Cinders »

My question is how many rows of rivets are in the seam? As long as it's more than one, I would think a hydro test would be a good starting point
-Tristan

Projects
-2.5" scale Class A 20 Ton Shay

Steam Siphon: https://www.shapeways.com/shops/leavitt ... tive-works
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Dick_Morris
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Joined: Sat Jan 04, 2003 2:09 pm
Location: Anchorage, AK

Re: Lap seam, riveted boilers

Post by Dick_Morris »

Bore scopes that you can use with a cell phone are cheap and can be used to inspect the interior.

How big of a boiler are you talking about? Steel or copper? What is the design (i.e., locomotive, vertical fire tube, or ?)?
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NP317
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Joined: Tue Jun 24, 2014 2:57 pm
Location: Northern Oregon, USA

Re: Lap seam, riveted boilers

Post by NP317 »

Best test method is probably ultrasound.
I'm not sure what modern improvements offer, but "shear-wave ultrasound" used to be the chosen method for looking "sideways" into rivet seams.
~RN
John Landrum
Posts: 31
Joined: Fri Feb 17, 2017 2:05 am

Re: Lap seam, riveted boilers

Post by John Landrum »

All good info guy's! To fill in the blanks, the boiler is for an 18" gauge locomotive and is about 6 feet long (the pressure part) there are three rows of rivets on the engineers side of the boiler and they run the length of the boiler from the rear tube sheet to the smoke box front. I would guess the diameter of the rivets at a minimum to be 1/2" the heads are conical and about 1/2 dollar size. I will post some photos of the boiler seam tomorrow.
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