The last StewMac calipers I used were rebranded I Gauging calipers. All of these cheap Chinese made calipers are of adequate quality for measuring but they are a long ways from being a truly high quality instrument for measuring anything very critical. They also eat batteries at an alarming rate too. The measuring part never really turns off. Only the LCD display actually turns off. A milliammeter will show current drain when the calipers are supposedly turned off. Mitutoyo calipers show zero current drain when they are turned off, but those are $250-$6200 calipers. I have the 8 inch carbide anvil Mitutoyo calipers which are about $500. They measure in .01mm and .ooo5" increments. I like having the 1/128th or 1/64th or 1/32nd or 1/16th or 1/8th or 1/4, or 1/2 of an inch measurements! Mitutoyo does not offer that feature in the carbide anvil sets. You have to re-zero any caliper set, any micrometer and especially dial gauges every time you go to use them. Changes in temperature make the metal expand and contract enough to throw the measurements off, especially with dial gauges. We have an old wind up 8 day clock. In the summer it needs to be readjusted or it runs slow. In the winter it needs to be readjusted or it runs fast. What happens is the pendulum expands with the higher temp in summer making it longer so the weight takes longer to swing back and forth. In winter it contracts and the pendulum swings back and forth faster because that pendulum rod is shorter. My dial gauges' racks can grow or shrink by 50-200 1/10,000ths of an inch with seasonal temperature changes. I wish I could keep every part of room in the house at 74 degrees F, but it ain't ever gonna happen. And yes, that Ames Waltham dial gauge measures down to 5/100,000 of an inch and it is repeatable to 1/10,000 of an inch or 10x more repeatable and 20x more accurate than most micrometers and calipers. Waltham also made fine American watches. For calipers that measure in fractions of an inch, I am using I Gauging. I also use I Gauging straight edges. For a while StewMac's straight edges were I Gauging's rejects. They were about 1/2 as accurate as an I Gauging straight edge but still accurate enough for luthrie, I guess. The I Gauging straight edges cost about 45-60% less too. I'd buy two 36 inch straight edges and cut them into pieces, so I had 6 inch, 12 inch 18 inch, 24 inch, and a 30 inch and some odds and ends pieces. I have a hand scraped Starette of two that are accurate to 1/1000th per 3 feet. Those are $3500+, and used for very fine machine work, like decking the heads on a Rolls Royce Merlin engine. I do NOT buy calipers, dial gauges, straight edges or micrometer from StewMac. I can get better quality stuff, even if it's Chinese made, non Mitutoyo stuff, cheaper elsewhere and the quality is almost always better that StewMac stuff, by a factor of 100%. These tools are NOT luthrie exclusive tools. Put the words "luthrie" or "gunsmith" in front of any tool's name and the price always goes way up.
