Found them! Yes, with both irony and ignominy aplenty.
This is all part of a space allocation improvement. Moved some junk out of the mech workshop room, reassemble that table in the freed-up space, and put up some shelves on the wall above it. Which then allows me to move some 'mechanical' stuff out of my electronics area, into the mech workshop room where it belongs. Among other things my stock of nuts and bolts. Some of which is in parts drawers, and some in original boxes from suppliers.
With the shelves up now, I was sorting out boxes of fasteners while hunting for the boxes of bits I need for construction of a stand for a big sheet metal working machine. Discovered that for some reason back in 2013 I thought putting the bolts from the table in a box labeled "M10 socket head cap screws" was a good idea and I'd remember that actually meant "1/4 inch cup head bolts from the table." There's the ignominy.
The irony was in opening that box on the table for which I needed them last week. Much too late.
That's one mystery solved today, but with another one taking its place. The missing roller castors.
The stand to support the sheet metal folder needs four very heavy duty castor wheels. Only for moving it around, normally it will sit on screw-down posts so it doesn't move.
I have two 19" equipment racks of the same kind, by HewlettPackard aka whatever their name is today. Each one had two really solid castor wheels, that I removed. The wheels are permanently part of a uselessly custom metal bracket, but with the most recent pair it occurred to me to just cut the useful part out of the bracket. So I had those two in my box of roller wheels, and if I had another two they'd do fine for the metal folder stand.
But can I find what I did with the two from the earlier rack? I'm pretty certain I didn't throw them out.
Don't want to wait till they turn up, so today bought 4 new castor wheels. The missing pair will turn up soon after I finish the folder stand.
Apart from those annoyances, this project is going well. It's having a lot of those little 'karmic thumbs-up' events that make one feel good. For instance:
* While buying some stuff for the folder stand at a place in my nearby industrial area, asked the guy if he knew where locally to get heavy duty castor wheels (Bunnings ones are so-so.) Turns out there's a great place that specializes in industrial castors just around the corner - Style Steel, 23 Fitzpatrick St Revesby. I did not expect it to be that easy.
* The old table turned out to be a PERFECT fit between the existing stuff and the end wall. Part of the row is a wooden base for a couple of bench sander-polishers, and I think I may have worked out the length of that to fit the future bench, a couple of years ago. If so, yay me for getting it right. Moving other things around would have been a huge amount of extra work.
* Buying the main steel beam to make the folder stand base, I needed a bit under 3m so asked for 3m at the steel supplier. This means cutting it from the usually 7m long sections. 100mm x 50 x 3mm wall rectangular section, is $18.83 a meter. Buying a full length is overkill and anyway I can't transport it on my car roof racks. (Well I _can_ but it's not legal on the road.)
So I'm there in the warehouse, and the guy pulls a length off the rack, and carries it over to the cutting machine. I think hmmm... that's not a full length, it's a bit over 5m. The cutting fee is $7.60. They'll be left with a barely salable 2m offcut. So I asked if I could just take it as is, for the same price. They agreed. Juuust short enough that they'd say OK, and also juuuust short enough that the warehouse guy would look the other way while I put it on the roofrack. Should really have brought the bumper bar bolt-on front support to be legal. But it's a short drive and back streets all the way.
Wheee... free steel, due to luck that they had a piece that size.
* Also at the steel supplier, when paying in cash the bill was $68.30. Turned out I had exactly $8.30 in coins in my wallet. I love it when stuff like that happens.