[kevinaston1]

From time to time, members need to measure this, but are unable to because of the silly prices charged for torque cassettes.

How about a gauge for under a fiver? Sounds good?

Torque on a cassette recorder is measured in g/cm. Since a cassette spool has about 1cm radius, measure the force applied to the rim of this and you have the measurement.

Scrap an old cassette and keep about 200mm of tape on each spool, at the end of the tape, tie a small loop.

Place the spool on the take up hub, tape on the left as the hub rotates clockwise. Hook a 0-100g spring pull gauge onto the loop and set the machine to play. Hold the pull gauge steady, and you have a measurement of the take up torque in grams per centimetre.

Measuring back tension is a little more difficult. Place the spool, on the supply hub with the tape on the right this time. Set the machine to play and SLOWLY (AND VERY STEADILY) pull on the spring gauge so it starts to unroll the tape. Not easy, but you should be able to make a reasonable measurement with care.

Individual spring pull gauges are available from Rapid Electronics, which is where I bought mine from, but there are many other suppliers. I bought a full set, since larger measurements are useful.


Finally, here is a story which will make you cry.

In the late 70’s, the company I worked for, distributed Audio Technica, who introduced a truly phenomenal mutitrack audio recorder called the RMX64; a six channel audio mixer with a 4 channel cassette recorder (standard and high speed).

I immediately placed a large order with AT Japan for a selection of spare parts so that I would be able to service any machine which came back. Along with the spare parts, they sent me a full set of standard and high speed test and alignment cassettes, in a mahogany case. I shudder to think what the value was, but it was probably around £1000 all those years ago.

At the end of 2012, I was made redundant by the company; to be replaced by two young panel/chassis swappers. A couple of years later, I spoke to the guy who was now in charge of the service department (no technical knowledge at all), to arrange to purchase some of my old test equipment and spare parts, one of which was said set of cassettes. He rang me back with a very good price on the test equipment and spare parts; none of which had been touched since I left.

What about the cassettes I asked? Sorry he said; we do not have those. I asked the lads in service what they were, neither of them knew what they were, and so I just threw them out.