Proper care of these items is crucial to retain their accuracy.

I once owned several high-quality Starrett measuring instruments, including several micrometers, a dial caliper, snap gauges, small hole gauges, and a dial gauge. These tools were necessities when I was a technician, used to take precise measurements of cylinders, valve stems, valve-guide bores, and a multitude of other precise measurements needed when rebuilding an engine.

While a couple of the shops I had worked in had various sets of these types of tools, other techs would nonetheless ask to borrow mine, since the shop’s tools were generally in a sad state and mine were pristine. I would let others use my tools on the promise that they would be handled with care, be used in the manner for which they were designed — a caliper was not to be used as a wrench; a micrometer not as a press — and be promptly returned.

These highly coveted instruments took me several years and a few thousand dollars to acquire, and back then they were American-made — some Starrett tools are now outsourced elsewhere. Each tool was tucked preciously away in its carrying case or box, which was placed in a dedicated drawer of my toolbox. For the most part, I trusted the people I worked with, so I left my toolbox unlocked.

When I decided to make a career change roughly 25 years ago, I left my toolbox behind at the final shop I worked at, to be picked up a few weeks later, since it was big and heavy, comprising a top box, a middle box, and a wheeled base. In this case, I had locked it. I eventually brought my toolbox home. 

It was only about a month after having retrieved it that I needed something in my toolbox. It’s then that I discovered it had been broken into. The only things missing were all my Starrett measuring tools. The crafty thief had pulled hard enough on the drawer containing only those items to bend the locking tabs, force it open, and empty it of its contents (he’d most likely borrowed them in the past, so he knew where to look). 

He then pushed the drawer closed, but since the locking tabs were bent, it wouldn’t lock and it stuck out just a tiny bit. To mask his evil deed, he then wedged a small piece of wood between the drawer and the tool box frame so the drawer wouldn’t open accidentally if the toolbox were to be moved, and it held the compromised drawer flush with the other drawers so as not to draw attention to it. 

After contacting the shop, where I had several friends, it was pretty much deduced that the culprit was a tech who’d left a couple of weeks after I did, to return to his home country, France. While unmarked, it would be too easy to identify my tools if they were to show up in that shop again, making them nearly unusable to anyone there. So, it’s very likely that my measuring tools left the country with him. 

I’ve since replaced most of them, but with much lower-quality items, since I no longer wrench professionally — the cost of replacing them with equivalents is just too high to be justified. I do, however, maintain these cheaper tools the same way I did my Starretts, since the information they provide is just as valuable. If you have some precision instruments, here are some care guidelines. 

I still keep my instruments in their original carrying cases to keep them clean and dust-free. If you don’t have a storage case, an enclosed cardboard box will do. I also insert a silica gel packet into each case to prevent corrosion. Another way to deter corrosion is to apply a light coat of high-quality, light-viscosity oil to the visible or sliding surfaces. Starrett 1620 instrument oil is made for this, at about $20 for 100 ml. Clean off the contact surfaces with paper when ready to use. 

When you’re done with the tool, return it to its case; don’t leave it out to collect dust. If it is dusty, never blow it clean with compressed air. Use your lungs and a lint-free cloth. Don’t put your tool down on a dirty workbench; place it on a clean cloth or paper. And don’t leave it near anything magnetic, since it can magnetize and will then collect metal shavings, which is not good. 

When storing a vernier caliper or a micrometer that measures to zero (the measuring surfaces contact each other when fully closed), store them with a small gap between the measuring surfaces, and leave the locking screw loose. This will help maintain accuracy since the body of the tool won’t be stressed by any temperature changes. And finally, keep them somewhere safe.