The last picture was of a Heep like Pelagro's that was done a few years back. The hat channels were mostly salvaged originals. We had purchased a straight section, and spliced in what was rotten. The white oak that acted as a stiffener/filler holds in moisture, and causes the floor to rot. To keep the channel from collapsing when the hardware was torqued, there were thick wall sections of 1/2" i.d. pipe welded in. So before the channel was installed the sections were painted with several coats of the yellow industrial primer from TSC, then a couple of coats of the por 15, then a couple of coats of etching primer. The mating surfaces were coated with weld through primer to ensure that there would be no exposed metal.
To answer your question, I had a spare frame that the dimensions all matched the original frame. I used it as a jig to ensure that everything fit correctly when mated to the original. Everything was tacked, then rolled over on its side for ease of welding.
I used to have 5 gallon buckets filled with Cat hardware. When Caterpillar changed their logo from the packman C, to the pyramid up the A. They threw out boxes upon boxes of perfectly good, never used hardware. Everything I owned or worked on had Cat hardware.
I put a shrinking disk on my Christmas list, just behind the shrinker/ stretcher I need for making the bottoms of the tool compartment on the wagon.
I'm with you Larrbeard, I had no idea what it was either until my friend that built a 32 Street Rod that took him 5 years to build told me about it. It fits on a big grinder and doesn't grind the metal it just heats it up a area with friction and the metal turns a yellow then blue color then you drench it with a wet rag or pour water on it and the sudden temperature change shrinks the metal from contraction the opposite of when you heat a bolt or nut that is heated up will expand to get it off. You can do the the same with a benzo-matic torch or cutting torch but the out come is very erratic due to you are heating up to much of a area in lieu of a shrinking disc heating up a small section area.
They work Great but it takes some practice to get it down.
Dumb Ole Excavator? Hardly. It takes a lot of talent to be a good iron hustler. I have had a lot of seat time in different machines, but can not be considered an operator. One outfit I worked for part time had a peat moss fire. I spent 20 hours in the seat of a 300 Kabelco excavator mixing water in to help put out the fire. I don't remember how many tanker trucks were dumped in the hole, but I'm sure it was enough to float a battleship.