Head to Head: Fractional Dial Calipers
With measurements displayed in 64ths of an inch, these precision tools are accurate and convenient
Five years ago, some brilliant entrepreneur came up with the idea of making dial calipers that could be read fractionally in 64ths of an inch (see FWW #157, p. 31), with one full revolution of the dial equal to 1 in. That invention provided woodworkers with an accurate measuring tool that didn’t require mathematical conversions from decimals to fractions.
Now, several other manufacturers have entered the market fray. I recently took a look at three distinctly different models, from Hartville Tool, Starrett, and Woodcraft, to see what you get at three different price points. All three tools are made in China of satin-finished, hardened stainless steel, and all three tested equally on the accuracy scale. But several of the details are quite different, especially the dial faces.
The Hartville Tool caliper costs about $30. The head moves smoothly along the bar via a serrated thumb tab or a wheel, and it features both a fractional and a decimal scale. The fractional scale is on a white background, but it’s a bit awkward to use because the scale is in the center of the dial, and my eye is naturally drawn to the outer ring.
Starrett’s model 1202F-6 caliper sells for $70 (www.hartvilletool.com). The dial also reads either fractionally or decimally, but the fractional scale is larger and very easy to read because it is printed on a bright yellow background. Head movement is activated with a spring-loaded thumbwheel that has virtually no backlash.
Woodcraft’s caliper costs about $50. It has one large dial face that’s extremely easy to read. The head movement is controlled with a thumb tab only — no wheel — so the travel was not as easy to control as that on the other two calipers that have thumbwheels.
Overall, I favored the Starrett because the dial was so easy to read and the thumbwheel had less backlash.