So it’s time for something proper. The local tool distributors carry a number of brands, and the ones I’ve been looking at are Mitutoyo (duh), Sylvac (Swiss) And Mahr (German). In fact one distributor has a sale right now covering a few models from each. (US brands are less likely to be available here.)
So what do I need to look for?
Since it seems you are most interested in feel and general quality I would recommend Japanese made mitutoyos.(Yes it does make a difference. I have a pair of 1cm dial indicators one made in japan the other in us. Same design same part number and the smoothness of movement, solidness, and general build quality are all much higher on the japanese made one). I also have a brazilian made mitutoyo dial caliper I use every day at work, and I can say it again suffers from being not quite as nice as the japanese models though still miles ahead of cheap chinese models
I know I want the thumbwheel (any reason why I wouldn’t want it?),
I find a thumbwheel easier to use when trying to move the calipers a short distance or back and forth over a measurement. My 12" calipers do not have a thumbwheel and I find it much better when I'm sliding a long distance, but trying to get right to final measurement is a little more finicky.
and ideally bigger digits. I also know the standard 6”/150mm is more than enough for me at the moment.
If you can I would recommend an 8". It can be surprising how often just a little more measurement space will help, and they're not nearly as big and ungainly as a 12"
I also don’t see any need for a data link. But what else should I look for? I assume IP67 rating keeps dust out and theoretically improves longevity, right?
IP67 is waterproof for keeping coolant from machining out. For regular use this isn't really needed
What about jaw shape?
Unless you know you need something funky go with the standard common jaws
Micrometer resolution?
I don't trust a caliper to tighter than .002/.003" really so I wouldn't spend extra on anything tighter than the commonly available half thou readout.
Square vs round depth gauge?
round fits in more spaces but is more easily damaged.
Carbide jaws? (Expensive!)
Really nice for high precision kind of a waste on calipers imo.
[Edit: since it doesn’t seem to be clear, I’m expressly asking for help evaluating which of those features make sense, because the range of models is overwhelming.]
Some models list “inductive” sensing. Others “absolute positioning”. What should I look for?
absolute is less prone to the jumps that have been bugging you, but on any higher end caliper this really should not be a problem.
For what it’s worth, I was using a mitutoyo recently and, just like the instructor warned me, it was hella easy to accidentally hit the hold button and thus inadvertently not take a new reading at all. Didn’t like that button layout.
They’ve also got some sets on sale, with a caliper, micrometer, and various metalworking tools. I don’t think I need a micrometer, but is it worth having?
If you don't need to measure something solid to a tolerance of less than .002/.003" micrometers aren't really going to do anything for you, especially since you will need several just to cover a small range.
My actual needs are modest. I’m measuring mostly things like screws, components, cutouts, etc. But I absolutely hate using shitty tools, I want something dependable and that feels good in my hand, where the parts slide smoothly without wobble, with great usability.
So, any advice? Unfortunately, I don’t think there’s any opportunity to try before buying, nor any real return period, so I hope the hive mind can help me out!
Thanks in advance!
I think I answered as many of your questions as I could. I'm not an expert by any means, I'm just a machinist who uses these tools every day so I have some opinions. My general advise would be to make sure you want a digital caliper over something like a dial caliper. I personally find the dial caliper easy to trust since I don't have to worry about batteries, or if I pressed the wrong button or anything else. Obviously some people will really prefer the general ease of use reading a digital caliper so that's up to you.
Based on what you've posted for your needs I wouldn't waste money on fancy features since pretty much any "name brand" is going to have the general feature set to make you happy. Most of my measurement tools are older American or newer Japanese so I can't comment on European manufactured items too much. I do have a couple swiss made dial indicators and I have found them high quality and smooth operating, but they always feel more fragile to me so I wouldn't recommend them as a main tool to be used and abused every day, but they are the ones I bring out when a measurement just HAS to be right.