Good tools are a pleasure to work with. I learned long ago that one should never buy cheapie tools. Harbor freight is the enemy! Ok, buy them cheap if you _know_ you’ll only use it once in your life, but the frustration and sloppy work that result from using crappy tools, not to mention risk of injury or ruining your project, will make your hobby/project/job much less pleasant.
I am a machinist for a living, and I use digital calipers literally all day long, every day. Also a digital micrometer, and good quality steel rules (they’re called rules, not rulers!). I’ve been at this job for 13 years, and in this profession for 21, so when I saw this post, I thought I’d chime in and share my experience.
These Mitutoyo digital calipers are great! They are very accurate, which is not always the case with digital calipers, especially cheap ones. Note the difference between accuracy and resolution. The display may show a .0001 difference, but the accuracy could be +/- .010 on cheap calipers.
They are also quite durable, and resistant to dirt and crud. Mitutoyo also makes a 4 inch version that will save you a few bucks if you don’t need the 6" measuting range.
On these calipers, the afjustment of the gib strip, (the brass wear strip inside the top) works well, and holds it’s setting properly as long as you don’t remove the adjusting screws for some reason.
Your calipers should have some drag when you slide them. (Not too much), and the Mitutoyos I’ve gotten are always adjusted properly right out of the box, if maybe a touch loose for my taste. If the gib is too loose, you will get inaccurate measurements, especially if you are the type who squeezes down hard when measuring. To test, hold the bar in one hand, and with the other, try to rock the slider in all directions. There shouldn’t be any play. If there is, tighten the gib screws, one at a time, until they gently bottom, then back off 1/8 to 1/16 of a turn. Personal preference does come into play here. The major source of error when measuring with calipers is differences in "feel" from person to person and caliper to caliper. So, adjust it so it feels right, and so you can get consistent measurements each time.
When measuring, you shouldn’t be squeezing. You should be able to slide the item you’re measuring out of the caliper jaws with a light but firm pull. There should be drag, but you arent clamping down like pliers.
These Mitutoyo calipers are great, but if you want the _best_ calipers, imo, spring for the Starrett ones. They cost more, but they’re worth it. Also, they’re made in the USA if that matters to you. Not a knock on the Mitutoyo, just my personal preference. I used the Mitutoyo exclusively for 10 years, I’ve moved up now that i’m able to convince my bosses to buy what I want, hahaha.
Comment by Gene Lewis — October 15, 2011 @ 1:40 pm