I'd guess that as long as cheap digital calipers have been available around that most people who play around in the shop (wood, metal, or more kinds) have a pair. A while ago, I saw the calipers on the top in this picture on sale at Rockler's and bought one.
As you can see, they're labeled General, a long established tool importer and seller. You can also see the main feature for these: they read out in fractions of an inch, down to 1/64. 1/64 is a bit critical for most woodworking, but they work just fine in the metal shop. Except for the fact that they're made of a plastic or glass-filled plastic and are therefore not as hard (in the scratch or dent resistant sense) as steel calipers would be. They also read out in decimal inches or decimal millimeters at the touch of a button.
Yeah, I have fraction-to-decimal charts around, and yeah, I have memorized lots of fractions in decimal format, but it's really convenient for things that aren't close to a multiple of 1/8, or a few others that are lodged in my brain. Plus, it's nice to measure something and know that if I measure .143, which isn't in my memory stack, it's "close enough" to 9/64. They're handy.
Unfortunately, they also act weird sometimes. They reset too often and that includes resetting zero or mode.
Enter the calipers on the bottom. A few weeks ago, Little Machine Shop listed them as a weekly special, and since they're made of hardened steel, that overcomes one of my objections to the plastic ones. Plus, I hoped the weird resetting was EMI and that more metal on the back of the electronics might help.
This is where the implementation issue shows up. I had to go through 3 sets to find one that works. The first one was fine when I turned it on for a first look, but then I put it aside because lots of other things were going on (it was a week before Christmas). When I tried to use them, they were dead. I opened the battery compartment and found corrosion fuzz inside. I cleaned that out and replaced the battery and found they were random number generators. They reset constantly, resetting mode and zero constantly. I wrote LMS to ask for an exchange, and while I was sitting here at the computer not even touching them, they would turn on by themselves, and choose random modes. It doesn't get much flakier than that.
The second pair arrived the Friday before Christmas and wouldn't turn on. The battery compartment in these was even worse; so full of fuzz it was almost pressing the plastic open. I wrote LMS and politely said if they would go through their stock and find me a set that worked, I'm interested, if not, send me a refund. LMS is known for good customer service and they quickly sent me a third set. These work much better than the other two. I've had them reset on me a few times, but it seems to come from sliding them open too fast. They will turn on just by moving the slide, which is different from all my other calipers, and I can't tell you if that's by design or not.
So do I recommend? When they work, they're pretty convenient, and I tend to keep mine with me, but that 33% success rate bothers me. I'd be more inclined to recommend them if you could visit someplace selling them and check them out, maybe pick out a pair yourself. I see a similar caliper at Horrible Freight and I'd bet that one or two companies in China Incorporated make them all. If you must order by mail, I don't like the odds of going through three to get one good set. I'll leave that up to you.
I'm resigned to just picking the battery type I want(2032 just because) and hope for the best.
ReplyDeleteHave you found any that use the CR2032?
DeleteThe battery issue with the cheap Chicom calipers is that they allow the battery to discharge even when it's "off". If you're not going to use them Real Soon, pull the battery. Most use LR44/SR44 batteries, which are thicker and smaller diameter. They are widely available and cheap to buy by the card, though.
I have had good luck with the Harbor Freight 6" digital calipers. Wait until you have a coupon or they go on sale for $10. I do have to replace batteries every six to twelve months.
ReplyDeleteThose look identical to the ones I bought at Harbor Freight.
ReplyDeleteProbably are, if nothing else in the same sense that Jet machine tools are the same as Grizzly are the same as HF. The tools we usually think of as higher quality get more attention at inspection and more rework.
Deleteyoutube channel AVE has a nice dissection of these called "Say hello to cheap Chinese calipers"
ReplyDeleteComeandmakeit
Found a channel called AVE and I think this is the video you mean, Bored of lame tool reviews? Shake hands with cheap Chinese calipers. 21 minutes 19 secs.
DeleteOne of the issues with the General is that there's no wheel for moving the sliding part. That makes it harder to get a gentle grip on the part, and the plastic will slip and hit metal harder than I'd want. I think that compromises accuracy somewhat too.
I have a few pairs of these around the shop. They always work. Maybe not the cheapest but mitutoyo has a good name. We've never had an issue with them :
ReplyDeletehttps://www.amazon.com/gp/aw/d/B00JPHK2NO/ref=pd_aw_sim_328_1?ie=UTF8&psc=1&refRID=RF72Y6WYA7XX2XVSJVY7&dpPl=1&dpID=71TR9qeo9zL
Just use a dial caliper. They have no battery problems...or any other digital unreliabilities.
ReplyDeleteHere, UTTERLY reliable:
ReplyDeletehttps://www.amazon.com/SE-780DC-Dial-Caliper-Only/dp/B0019O501A/ref=sr_1_2?ie=UTF8&qid=1484281746&sr=8-2&keywords=dial+caliper
If you need better than 0.001" you should be using a micrometer anyway ;-)
I have a pair of "Lyman" (Chinese) stainless steel electronic calipers (http://www.midwayusa.com/product/154410/lyman-digital-caliper-6-stainless-steel) purchased through MidwayUSA that work well (LR44 batteries) that I use for reloading that I have been pretty happy with. I have to re-zero them each time I turn them on, but other than that, they work well. Inch or metric (but not in fractions), and they do have the thumb wheel.
ReplyDeleteAs Irish said, Mitutoyo does make good calipers if you are willing to spend a bit more (https://www.amazon.com/Mitutoyo-Advanced-Absolute-Digital-Caliper/dp/B00IG46NL2/ref=dp_ob_title_def). Starrett are excellent, but too spendy for my limited use of calipers.
Also try these guys:
ReplyDeletehttps://www.zoro.com/search?q=digital+caliper&origin=sayt&price-max=100&price-min=10
If ya gotta have accuracy and digital, go McMaster:
ReplyDeletehttps://www.mcmaster.com/#calipers/=15w9akp
Not necessarily the least expensive, but they are reliable in everything they sell.
We have a half dozen or so SPI branded digital calipers around the wood shop.
ReplyDeleteChinese made. Look just like the one you posted. Guess what? They drain the batteries quickly. But the real bad thing is they ALL randomly drop .200". Measure .382", set it down, pick it up, and measure .182". happens in seconds, sometimes won't do it for weeks.
The only saving grave is it always drops the size, never increases it, so the part always reads undersize rather than over.
The cheap chinese digital indicators we have on some of the equipment does the same thing- drops exactly .200" on a random basis. fortunately we are so used to it we automatically check zero every time.
I hate it when a respected brand name is bought out, then used as a skin suit to market shitty product.
The Swiss made Browne and Sharp digital caliper we have is totally reliable.
From this, I have concluded of all places to save money, measuring equipment is the worst. Not only is the unit bad, but possibly every thing made using it.
Mickey M sells B+S. And Mitutoyo. And Starrett.
DeleteI bought the bottom one when I built my AR. They do come on when you slide them open.
ReplyDeleteThey've worked flawlessly now for two years.
Maybe, like most things today, the seller is as important as the manufacturer.