Description
A ruler with inch and metric side by side and red lines at the standard heavy hex nut sizes. When a nut doesn't measure what the paperwork says, this tells you whether you're looking at a metric nut.
Say the paperwork calls it a 2" nut, but your calipers read 1.95". Shouldn't it be 2.0? Lay this ruler across the flats and compare the inch and metric tick lines where they meet in the middle. 100 mm, for example, lands very close to 3-15/16". The red lines show you which sizes are standard.
Use it on loose nuts
Measure across the flats of a nut that's off the stud. On an installed nut the stud gets in the way, and you'll bend the ruler around it without meaning to, which throws the reading off. For installed nuts, use the Heavy Hex Gauge. It measures from one flat.
Details
- Inch scale to 6-1/2", metric scale to 160 mm
- Red lines mark the standard heavy hex sizes on both scales
This is the Across the Flats Ruler shown in my book, The Bolting Field Technician's Pocket Reference, which also prints it at actual size. It's one of the six tools in the Heavy Hex Pocket Cards.
For millwrights, bolting technicians and pipefitters sorting out inch and metric flanges.
