INCRATDPROT12 Pro T-Rule 12-Inch

I have had the 6 inch incra t-rule for a long time. I purchased this one because (1) it is twice as long and (2) it has metric graduations. I intend to build a project in metric dimensions and it is terribly hard to find a metric-only rule. I am a huge fan of this t-rule system. It has three main uses for me:The first is for accurate layout of mortises and tenons. This tool coupled with a sharp marking knife results in unparalleled accuracy. Usually when I lay out mortises and tenons with this I need only a couple swipes with a shoulder plane for a piston-fit. It is not really possible to get 64th accuracy with your naked eye on a ruler.The second is as a thickness gage when thicknessing stock. It is easy to sneak up on, say, a 1/2" thickness by resting the t-rule against the face of the stock and measuring thickness on the face scale.The third is using the end of the rule as a height gage for router bits, or setting your saw's rip fence some distance from the blade. You lay the long side of the ruler on the router table and read the height at the end of the rule. Or, rest the long edge of the rule against the saws fence and measure to a near tooth on your ripping blade. It is again very precise (to 1/32" on the edge)

The only thing you have to remember is for this level of accuracy, this is necessarily a delicate instrument - you can bend it up pretty easily. This has been transformational in my woodworking accuracy. Have routinely used this for low tolerance work and consistently made cuts that had my digital calipers confirming the accuracy afterwards.

Being anal retentive about accuracy I always revert to the metric system.For really accurate measurements of fractions of a millimetre I will use a digital vernier or protractor.Now I have the best of worlds when I need general measurement in both metric and standard imperial/SAEIt was scheduled to arrive in 3-6 weeks but I received it after 3 days.Thanks Amazon and Incra.Update May 2015One word describes this tool - PERFECTIONSublime accuracy

The precision marking holes on this ruler are just what I was looking for. The metric scale is very helpful too since I do a lot of work with metric measurements.The ruler is somewhat flexible, but I would not try to measure a real tight circumference.The T-bar is handy for specific jobs, but the most appealing feature is the marking scales.The T-bar is 5 in. (127 mm) long, 11/16 in. (17 mm) wide, and 7/16 in. (11 mm) thick, secured to the ruler with thumb screws and nuts in a channel.

I opted for the larger and more expensive 12" rule thinking I'd opt for the better tool, but now that I'm using it I'm finding the second 6" are hardly ever being used and very often are getting in the way. THE RULE IS ABSOLUTELY PERFECT... I just SUGGEST you strongly consider opting for the 6" INCRA Pro T-Rule.