1) Close gauge to confirm calibration
The FB chain wear gauge has been precision manufactured and accurately toleranced.
The manufacturing process includes calibration referenced back to National Calibration Standards with each unit undergoing thorough final inspection.
While the instrument cannot be adjusted for calibration, it can be checked by simply closing the slide fully and reading from the 'Percentage Wear' window the accuracy to tolerance.
In the unlikely event that the instrument moves out of calibration into the ± zones it will be as a result of wear to the moving components and should not, therefore, be used other than as a guide.
Similarly, if the 'V' jaws are damaged, the instrument may not perform accurately.
2) Identify the pitch
The nominal pitch of the chain must be measured over the pin centres of one of the OUTER link plates.
To assist in this the instrument is provided with three separate pairs of red arrows.
Utilise one of the pairs located on the edges and the centre of the gauge. Depending upon ease of access to the chain one pair will be more suitable than the others.
Locate the arrows over the pin centres of the chosen outer link plate and the nominal pitch of the chain will appear in the 'Pitch' window on one side of the instrument or the other.
Select and use the correct side of the gauge relevant to the measured nominal pitch as follows:
Once the pitch has been determined the number of pins (n) that the chain wear is to be measured over will appear in the adjacent 'Measure over Pins' window.