Review on 📏 Starrett 66B Thickness Straight Gauge 0.0015 - 0.035 by Edgar Gomez

This Starrett gauge is way more expensive than most similar functional gauges offered by Revain, so... is it worth it? It definitely looks nice. When you hold it in your hands and look at it, you can feel that it is well designed and made with love. Small details evoke a sense of quality. The blade holder is strong and well polished, the locking mechanism is metal and big enough to grip, the markings on the blade are laser engraved and easy to read etc etc. But is it accurate? If you gap a spark plug you don't need it, but if you really want to know the gap between two surfaces that should never touch, can you count on it? I decided to tackle this issue by doing some quantitative research. I measured each blade in three places that were important to me. Position (A) is at the end of the gauge, centered across the width but set back about 3mm from the end. Position (B) is at the end of the gauge where any burr present will compensate for the distance measurement as it is being inserted. Position (C) is in the left "corner" of the end of the blade. This angle is the transition from the rounded side of the blade to the sharp edge of the blade. This is where burrs can become a problem when the blade is inserted from the side rather than the tip. The gage faces are 0.275 and 0.375 in diameter, so there is some overlap in gage range. A summary of the data is presented in the graph, where (A) is marked with a blue diamond, (B) is marked with a red square, and (C) is marked with a green triangle. The graphic shows the measured deviation from the marked value for each blade. Some of the blades were excellent with very little deflection. For example, a 0.017 inch diameter blade showed an error of 0.00002 on the leading edge (B) and less for points (A) and (C). The estimated measurement uncertainty is probably in the range of +/- 0.00004, so the "error" with this blade is related to the measurement sludge. All other blades performed well as expected (Starrett doesn't specify an accuracy, so I only expect a blade to be less than half the distance to the next smaller or larger blade. This will be +/- 0.0005 for all but the largest be) . The only exception was the .008 blade. The left angle measurement was 0.00864. Under the microscope, the left corner had a small burr at the transition from a smooth to a sharp edge. A few light taps with a thin diamond file eliminated this and brought the reading down to 0.00803. Other large discrepancies between the A, B, and C locations for other blades are also likely due to very small edge burrs. The worst deviation for a set of 31 blades (after correcting the .008 blade) was less than .0003, which is well above my expectations. So is it worth it? For me the answer is definitely YES! This is a product from a manufacturer that values quality.