Get these digital calipers for a super-low price with promo code

Originally published at: Get these digital calipers for a super-low price with promo code | Boing Boing

Checked 29 minutes after the OP posted:
Screen Shot 2021-04-23 at 1.47.19 PM


In addition to being out of stock, these are plastic calipers. For a few dollars more you can buy still cheap, but more accurate metal ones.

I get going cheap on tools one doesn’t use often, but maybe not quite to all plastic and rock bottom when it comes to precision measurement tools.


Yep. No longer available. Will the code work with other models or brands?

1 Like

I’ve looking for some digital calipers. I want ones that don’t eat batteries. All of the cheap ones will drain the batteries in a matter of weeks.


Possibly useful tip (though mine are metal, not plastic):

I have a very ancient set of digital calipers and they worked very intermittently. Swapped batteries more than once, thinking they were the problem. They lived in my workshop/garage - unheated, and it was winter when I had the issue.

Brought them into the house to see if I could find a fault, and they worked just fine once they warmed up. Maybe the metal is part of the problem, but they did seem to either work intermittently or give wrong readings when very cold.

1 Like

I looked on Harbor Freight and they appear to have some decent sets in the $15-$19 range.

This is a bargain compared to Starrett / Mitutoyou at 10x the price.
(If I was using these professionally, and for longer than one project, the Starrett / Mitutoyou ones would be my go-to choices.)

1 Like

“Carbon Fibre”.

I suppose there’s a market for calipers that aren’t suitable for machining.

1 Like

Perhaps someone drops several carbon fibers into the pellet hopper of the injection molding machine? :thinking:

Otherwise, “carbon fiber” seems rather unlikely at this price point.


I dont use my calipers often. In fact, the last two times I went to use them the batteries were dead, and I had none of the cursed teeny tiny batteries in the house. So I went to harbor freight and got a mechanical one. Works great. No batteries.


I’ve seen plastic calipers used in the watch and jewelry communities to measure things that you don’t want to scratch. Of course it’s not as accurate as hardened steel, but it does the job - especially when you want big numbers shown clearly in a video.

And lose precision as the batteries get weaker.


Digital calipers suck. Dead batteries, can’t be read in poor lighting, no indication as to actual precision…

Dial calipers that cost the same amount are almost always superior.

1 Like

Exactly. Buy the metal calipers and avoid the dead TV remote feeling.

There is no real need for a digital display on something like this.

1 Like

Well, I was going to buy a dial caliper for the exact reasons you note, but then I saw that the inexpensive digital model would read directly in mm, decimal inches or fractions. So my mathematically challenged self bought the cheaters… :-/

(And then the one that arrived didn’t do fractions as described, neither did the replacement. Sigh. Probably should have gone with the dial caliper.)

My caliper I paid 13 bucks for has both units. Problem solved!

Honestly these cheap digital calipers have way more reliability and accuracy than they have any right to be at the prices they can be produced for. It’s a testament to the dimensional control that is inherent and inexpensively achievable in PCB design. This teardown shows the capacitive vernier method used in these :

I’ve compared Mitutoyo’s with the cheapo eBay ones and the cheap ones did fall somewhat short in terms of slop and holding a position (if they even have a set screw for that) - but in terms of tracking relative offsets the measurement mechanisms are surprisingly similar.

There’s something cool about how vernier scales were originally for ease of us eyeballing tiny movements on a device and now the same principle informs circuit’s spatial senses.

(re. batteries dying - a lot of these have a function that automatically activates the LCD if a movement is detected (sometimes due to vibration or background randomness) - even when “off” i.e. the battery ends up being run down while in the drawer or toolchest)


Auto-shutoff is a must-have, perhaps 3 or even 5 minutes. Shorter if it can still read the encoder-ish thingy that provides the position data. Just turning off the display probably saves lots of power.

Also, support your local Harbor Fraught or Princess Awful. They have lots of cheap but plenty OK options. If you need more accuracy/precision/features/brand/etc, you’ll have to go much higher cost.

paging Quillette wrier Andrew Sullivan, who seems to sure love craniometry

I recommend iGaging Absolute Origin calipers.

As someone who uses calipers a lot digital ones save a lot of time.