Simon, in case I find the instrument is actually working in the right direction I might be interested in the gearbox of yours if you would sell it.
Cheers,Michael
Cheers,Michael
Some people incorrectly interpret this as if they have x-ray vision and can see the cable rotation through the case. To repeat what David wrote in different words, hold the speedometer/tachometer with the bottom facing you. If the cable needs to turn CW to operate the unit, it's a CW unit, and vice versa.The direction of the tach head is based on the "point of drive",
If you have a reversible, battery-powered drill, you can look up the manufacturer's specs. My Makita is two-speed, with maximum speeds in the two ranges of 550 and 2100 rpm. The precise values don't matter because they are different enough that it's possible to determine if your tachometer is 1:1, 2:1 or 4:1. Assume the latter to start with and use the low speed. If the tachometer registers anywhere near 2000 rpm, it's 4:1, ~1000 rpm is 2:1, and ~500 rpm is 1:1. After you've determined the ratio, switch the speeds on your drill to confirm your findings.Obviously the ratio is not quite so easy to check.