steam loco boiler jacket clips - what are they, what do they look like?

[mmagliaro]

Running along the top of most steam loco boilers, from the firebox all the way to the smokebox,
there are these little holders, clips, clamps, um, what ARE they?
I've looked at a lot of photos, but none that are really close up enough on the top of an engine to
see what these things look like and how they work.

The look like they might be some sort of nut/bolt or turnbuckle device that pulls the boiler jacket sheets
together along the top line of the engine, but I really do not know.

I'm thinking of modeling them with some sort of series of little nubs in my current project.   I've noticed them
forever, but in N Scale, they are so small that I leave them out... but maybe not this time 

Here's a pic from a brass loco:

[Chris333]

? 

http://britanniabuilder.com/Kit18bcladdingclamp.jpg


Looks like a standard small micro nub will do. 


http://www.locopainter.com/store/product.php?id=1166
click pic for bigger pic.

[superturbine]

I have castings of the boiler clamps but they take a lot of work.  Here is a pic, although not the best, of my N scale ATSF 3800 Casting with boiler clamps.

[mmagliaro]

Aha!  Yes, I see how they work now.   Hmmmmm.... I do have some ideas..... Bwa ha ha ha.
Thank goodness for ScaleHardware.com's inhumanely small nuts and bolts.

[mmagliaro]

Any idea how big these things really are?   Been through drawings and lots of photos.
Chris' one photo showed one pretty close-up, but that guy's engine is a scaled-down steam engine.
Up on top of a great big real boiler, would these things have, like, a 1" diameter bolt in them?  Bigger?  Smaller?