O has commented on my earlier post on replacing the belt in Rondinax tanks. Because comments are sometimes difficult to find I am copying it to a new post:

Hello user, this may be of use. I have fabricated a new belt for a Kent 20 (Rondinax 60 clone) which may work for you and hope the instructions below show how to make an identical one.

Materials required are a “checked laundry bag” (you will probably recognise if you do a Google image search) and a “snap fastener” (often used to fasten clothing.

(1)Use scissors or craft knife to cut a strip of material 8¾in long by 2¼in wide.
(2)Cut the strip down so it is
(a) 2¼” wide for ¾” length at one end (“stopper” section),
(b) 1″ wide for 1½” length (“threader” section through centre of spindle) and
(c) 1½” wide for the remaining 6½” to the end (“load” section).
(3) The cutting should be such that the strip is symmetrical along its length. Ensure corners are slightly rounded; you may want to ensure that the widest section is slightly arrowed – this section goes through the spindle to the other side to hold it in place, so you may want to shape it so it does not slip through. The thinnest past will remain through the spindle.
(4) Around ¾” from the narrower end cut a rectangular hole (rounded corners) about ¾” wide (ie across width of strip), by ¼”. This hole allows the clip to fit through.
(5) Cut an “I” shaped piece of material around 2½” long, 1¾” wide, trim middle to fit hole made in (4).
(6) Sew snap fasteners into the broad sections of the smaller “I” piece, thread through the hole made in (4).
(7) Thread fat end of long strip through spindle, test to ensure it can wind on etc.
(8) Wind strap onto spindle, hold in place for a day or so with string / rubber band (ribbon is quite good as you can use the snaps to grip and tie it round.

If you use small snaps they may be able to puncture the film to create a good grip, though if you use too much thread to attach them they may not clip properly, if you use larger clips you might need to pre-punch a hole in the film with a clipper similar to one used by train guard. You may need to dig out circles of negative from the snaps if you don’t pre-punch the film.

I have noticed after pre-punching a hole with the small snaps the larger snaps can use the hole as a pilot, avoiding the need for a punch – perhaps the design can be improved to use two sets of snaps, smallest furthest from spindle to “chew” the film(?).

The bags should be available from a small cheap plasticware/utensils shop, they bags are made from a thin, tough fairly smooth plastic. Snap fasteners can be found in large supermarkets, department stores, eBay etc; I tried 6mm and 11(ish)mm variants. Use non-rust snaps if possible, though they still seem to slowly corrode.

This has worked *fairly* successfully for me, though seems to work better if the film has been fully wound onto its spindle from the camera and allowed to sit for several hours, presumably acquiring a more even curl. You may want to experiment with the strap length as I have never seen an original Kent 20 / Rondinax 60 belt. Please don’t sue if wedding pics destroyed etc. Apologies for typos &c, sleepy.