A busy couple of days working on the photography stands. My solution to fixing the cheeseplates to the towers was to use hot melt glue. This was a tad nightmarish, as hot melt glue tends to set instantly when touching the cold metal, but after 2 attempts on Tower A, and 3 on Tower B, scraping off in between, the two were fitted closely enough, certainly under 1mm height difference. Once initially stuck, I filled the little oval lakes with glue, then screwed them flat.
After that, fixing the L-brackets to the footplates, which was a matter of lining up the towers, which stood well by themselves. Everything was accurate, so I glued the L-plates to the sides with superglue first, and 10-mins later laid them down, drilled and screwed, so these were exactly in the correct place.
Here's the tower top, with 15mm tube holders.
I didn't consider at first that the footplates will need to be removable. There's no way I could store these huge things when assembled, and they're rarely needed, so a next step was drilling the footplates (by hand) and fitting M4 rivnuts so that I can bolt and un-bolt the towers to the bases. After drilling 4 per side, only about 2 each side were accurate enough - these have be be very accurate, much more than 1mm. 2 out of 4 is fine, but in retrospect I could have done this better. I managed to fix one fairly easily, by removing it, drilling the hole bigger, inserting the rivnut edged with thick superglue, then assembling the top. The glue takes a few mins to set, allowing me to bolt it together and allow it to set in the exact correct place.
Today, testing. It's already a lot easier than the tripods, but they are not quite perfectly lined up, which in retrospect should have been expected. Lining these up to be straight over the lengths of a metre-or-so would be nigh on impossible by hand. The solution is to permit calibration. This pair are always used in tandem. It seems that a twist of 14mm on the 600mm width will set them just about right (to about -/+1mm on the 840mm length). It doesn't actually matter that much anyway, the skew would mean a similar skew on the photographed paintings, but still, it would be nice to get things as good as I can manage.
My plan is to fit another accurately glued rivnut, M6 this time, on the front right edge of the footplate. This will fit a rounded-headed bolt to be screwed in or out to calibrate perfectly. Once done, it will probably never need touching.







