Tolerance B2B Gauge

[Winander]

I purchased a B2B gauge from Alan Gibson because the Stores were out of stock and "AG supply them anyway".

I've just thought about checking it and it is 17.70 at the right angle, but the legs seem to be 17.61. Isn't the minimum B2B 17.67?

Have I been sold a pup, or could it be the inaccuracies of the cheap electronic calipers I'm using? Should I be worried?

regards

[mickeym]

Isnt that within the tolerance +/-

[grovenor-2685]

Isnt that within the tolerance +/-

No, reference to our standards, http://www.clag.org.uk/p4standards.html the BB is specified as 17.67 min - 17.75 max, hence the 17.61 is out of tolerance, 17.70 is OK, but since the ends of the legs are the most used part for checking the gauge is not satisfactory and should be returned (Subject to checking the measurements).
The other common use with L shape gauges is to use them as a spacer when pressing wheels onto axles. If the two sides of the gauge are not parallel as indicated here, then the wheels will end up with a wobble.
A gauge should be within tolerance and the two sides should be parallel.
Regards

[mickeym]

Thanks
I did think that as you say is correct, but I kind of assumed the product would be right...... assumption eh!

[grovenor-2685]

Hopefully not all the stock will be the same and Colin will be able to change it for you.
NB. AG Catalogue says it should be 17.7
Regards

[Winander]

Thanks Keith, much as I expected. I'll check it with another caliper before I return it. I suspect the caliper I am using requires a new battery.

regards

[Terry Bendall]

About 8 or 9 years ago the committee became aware that some gauges being sold were not within the tolerances so a number were bought from different suppliers and checked. The manufacturers concerned were advised where gauges did not meet the specification. Alan Gibson (Workshop) has changed hands since then and as others have said, I am sure that Colin will rep0lace it.

I suspect the caliper I am using requires a new battery.

It may be better to use a micrometer, rather than a vernier caliper and a manual one will of course never need a new battery.

Terry Bendall