Rubber drive band tension table/formula anywhere?

I'd like to hear your methods; I recently made a flat drive band for a Smith Corona "Data Disk" (Quickdisk) "floppy" (serial spiral reading) drive by cutting a band taken from a 1979 vintage 5 1/4" full height floppy to size and stitching the abutted ends with nylon thread and a tiny needle. It works without much of a bump at the joint, but if there are other methods that have less of a discontinuity, I'm all ears.

Michael

On square and round belts, I've had surprisingly good, longlasting results with crazy glue, a clean razor blade and a teflon v-block. On flat belts, your stitch method may be the best.

Likewise, similar success. A good quality cyanoacrylate glue does an excellent job on 1.2mm square section cassette belts. As John says though, it is necessary to get a very clean and perpendicular cut at the two faces to be joined. Once the joint has been made, a piece of very fine wet and dry paper can be used to remove any glue that has exuded from the joint. This can be done with the belt stretched over your finger. If you are successful, the joint is barely visible without magnification, and will stand a substantial 'stretch' test

Arfa

I remember when Superglue first came onto the market, there was a TV advert campaign where a bloke sliced a (fairly hefty) round section rubber belt in half, then superglued it back together. A few seconds (apparently) later he stretched it between a pair of parallel bars (gymnastic equipment) and then sat and bounced on it without falling onto his arse. Quite impressive, if it wasn't faked.

Gareth.

Like the guy who was 'Solvited' to a helicopter!

Ron

I have an 'O' ring kit from a top name maker. Designed to allow you to create your own special sized O rings. The kit has a supply of rubber, a cutter designed to cut the ends straight, a jig to hold the ends square, and... A tube of super glue to glue the O ring together.

I thought, wow that's one thing that will never work. One day I needed an odd-sized O ring, and tried it. Dang, once done it was both impossible to see where the joint was without a magnifying glass, and the joint was as strong as the rest of the O ring.

Increasingly off topic, but remember the "Barratt Houses" advert helicopter that flew under a bridge? Probably totally illegal these days. Especially with someone Solvited to it.

Gareth.

Yeah, they`d probably get a pasting from the authorities.

I`ll get my coat

Ron

Ha! I remember that too ...

Arfa

You were lucky that you didn't compress the glue joint. Just squash the joint with a pair of pliers and watch it crack open.

We tried the same thing, probably with the same kit, to make o-ring seals for a marine antenna. The problem was that the Cyanoacrylate adhesive was kinda brittle. I could stretch the o-ring and it would (usually) not break. however, if I crammed it into a machined slot, and compressed the o-ring with a matching plate (to make a pressure tight seal), the glue would crack, the joint would open, and the seal would leak. The same thing happened when I tried making an emergency o-ring seal for my shower valve. As soon as the joint was compressed, the glue would crack. I could minimize the problem by cutting the o-ring at a 45 degree angle. That gives a larger surface area and a cushion to prevent cracking. However, the cut had to be perfectly aligned with the compression angle. Rotate 90 degrees, and once again, the glue would crack.

Interesting comment, and next time I'll watch for that. IIRC, (Have not recently checked) the instructions did say to try to make the O-ring slightly smaller then the original. Of course that won't work in all situations!