Mike - I understand about the time. That's why I retired ..... now have even less with more honey-dos added to my platter
Phil - why does the UK get all the 'interesting' gadgets that seldom if ever appear here
I'm not going to ask you to pull your tensioning device (for lack of a better term) apart - as that time bug-a-boo noted above. A component scan will be great for me and probably others to look at and maybe come up with a workable alternative. I would bet that a couple of coil springs on a platen with a center Acme thread for major adjustment Those 2 springs on either side, individually adjustable - along with mounting hardware would work in lieu of a leaf spring. A fairly light duty leaf spring might be hard to source. Hmmmmm - love fabrication projects - but again, time as the current honey do list includes a new bath tub and surround(arrived this morning), kitchen counter tops, floor and new lighting.