Most of us use calipers when working with our 3D printers. Not [Albert]. He has a clockwork caliper design that he 3D printed. The STL is available for a few bucks, but you can see how it works in the video below. We don’t know how well it works, but we’ll stick with our digital calipers for now.
The digital readout on this caliper is more like a sophisticated watch. A window shows 10s of millimeters and two dials show the single digits and the number after the decimal point.
While we can’t validate its accuracy and we imagine it would depend somewhat on your printer’s abilities, we can say it looks pretty amazing in operation. This would be just the thing to be in a movie about an alien or post-apocalyptic machine shop.
Like a real set of calipers, there is a depth gauge, although watching it spin through the measurement is a lot more entertaining than the usual measurement. Towards the middle of the video, you can see the parts involved. As you’d expect, the main part is a rack with pinions driving gears that move the numbers and pointers.
Probably not very practical, especially when a reasonable set of calipers doesn’t cost very much anymore. But great fun and would make a nice show project for your 3D printing skills.
We have to admit that these calipers would be easier on batteries than the pair we use every day, but then again there are other ways to solve that problem. If you want a crash course on how to use calipers to reverse engineer mechanical parts, we can help.
Very interesting take on dial calipers, I can see this being useful in a future situation where the vernier has got lost.. or you didn’t know you would need one but do have the ubiquitous 3d printer – perhaps on the ISS for instance – though that would be improved if the shafts/screws were 3d printed snap fit or something.
Quite simple and logical to read, and the precision should be about as good as guestimators (we aren’t talking screw gauge micrometers here) can ever do, working on the same principles to reduce error in constructions effect on measurement. At least if you ignore the made in plastic extra flex under loads, and even if you don’t more than sufficient for most everywhere you would need calipers.
Though of course all this assumes your printer is calibrated well enough and accounts for plastic shrinkage as it cools etc – I find on one roll I’ve been using I need to add an extra 2-3% x+y scale as this one shrinks like buggery – so is also rather hard to keep from warping. Still looks like an easier tool to create with relatively low precision easy access tools like 3d printers.
Since this doesn’t require large parts, significant tensile strength, or even significant depth I’d say this would be a good candidate for resin printing which would protect it from some of those flaws.
On the other hand, while those flaws might be magnified by a low end PLA printer, that might not matter as much in a boot-strapping situation where you don’t care about accuracy as much as precision while using your crappy tools to make better ones.
there’s a distinction to be made here – it may not be super-Precise, but it has good Repeatability. and when you’re using the same measuring tool for all your figures, such as in the mentioned bootstrap scenario, repeatability ranks higher than absolute precision
For those who don’t want to or can’t pay, there are other options:
Imperial:
https://www.thingiverse.com/thing:187267
Metric
https://www.thingiverse.com/thing:1667195
These doesn’t have nice numbers/markings like the one in the article, but should still do the job.
It wouldn’t take much to make this synchromesh to relieve some of the backlash or add extra dials to increase the precision.
More dials would give you more reported significant figures, but even Starrett or Mitutoyo stainless steel dial calipers only measure to 0.02 mm. An extra dial for 0.01 mm increments on an instrument like this would be false precision; just random noise.
I wonder if compliant machine would be better approach. For example stack of parallelograms amplifying at each stage linear motion of jaws, finally driving indicator of readout. No backslash and repeatability problems. All you have to worry is characteristic – linear by design or canceling unlinearities between stages.
My digital calipers are kind of crap. Can anyone recommend a set I can get for a reasonable price? I know that I can spend $100 or more and get a great pair, but my use case doesn’t justify that kind of cost. I’m looking for something in the $20-$50 range. I am aware that this might just be the “crap” range of calipers, but I’m hoping someone can suggest something that’s less crap and more good enough.
Thanks.
I have a 4 € (incl. shipping) PA66 (plastic with carbon) thingy from china. It has reliable 0,1 mm resolution checked against gauge blocks. Only drawback: edges can not be used as scriber.
Meets my demand and expectation.
“Hacked” it with an AAA-battery holder.
I don’t remember what mine cost, but it was probably between $10 and $15. My problem is that I get different measurement every time I measure the same thing. If I am trying to model something, say a push button, I measure the width, and it will come in at 5.897 mm, then I open the jaws, and measure again, and it comes in at 6.021. It’s more than just +/- 0.1 mm.
It’s a Pittsburg Model 47260, and the manual says it’s accuracy is “To 0.001” inches.
Maybe it is, and you’re measuring a slightly different spot
While I would never rule out human error, I’m talking about measuring something like the square base of a tac switch, or the diameter of the button itself. You really can’t get different spots on that. I was measuring it at the tip, but found out that the caliper could flex and you should measure at the base of the arms. I switched to that, and it got a little better, but not much.
My daily driver (i.e., not my more trustworthy analog Lyman or better Mitutoyo) is a Harbor Fright 6″ Pittsburgh. No apparent model# on it, but other than the length it looks the same as your 8″ 47260. It works like a champ, with none of the non-repeatability you describe. It also has super-good battery life.
I have another Pittsburgh, model #68304, that is nicer and has an easier to read display, but chews batteries. My Mastercraft (Mastercrap) is even worse.
Easy test: close jaws, zero, open wide, then close again. Still zero? If so, they’re probably fine. If not, then throw them away immediately and don’t look back.
Fake Mitutoyo from ali – seriously! Crap battery life BUT they are made very well. I was surprised how nice they are. Setting moral aside, best choice atm.
* – no affirmation, just observation.
I really like my iGaging Absolute Origin calipers. Plenty accurate, very user-friendly, and the battery lasts years.
I’ll second this, I like mine much, much more than the typical $10 pair that everybody seems to have. The battery life is well worth the premium on its own.
I’ve also read some good reviews of iGaging, and was considering buying one…
Then I thought of the amount of crappy callipers I’ve bought and trew away , either because of very crappy quality, too short battery life or “just stopped working”, and just bought a real mitutoyo for EUR100, and it still works smooth and supple on it’s first battery and I have it now for approx 3 years.
If you don’t want to spend that money, iGaging and a few others are apparently reasonable. Callipers of EUR20 or cheaper are usually crap, but between EUR 30 and EUR50 there are a few decent candidates.
In 2010 I paid $20 for a Shars 6″/150mm *dial* caliper on eBay. It’s served me so far for my hobbyist purposes. I haven’t tested them against gauge blocks, but at least I don’t have to worry about batteries or badly printed capacitive plates. They’re now $42 at eBay (discount_machine). People on Reddit like them as well as iGaging.
Genuine Mitutoyo. Just spend the money.
My point is I own a set of Mitutoyo digital calipers, which I bought about 20 years ago. They are awesome.
Brown & Sharpe and Starett are awesome too as a dial and Vernier caliper. I’ve owned those brands as micrometers also along with the Mitutoyo second hand. My height gauge is just a Vernier Brown & Sharpe.
Recently some other micrometer models to restore successfully.
Way easier than hauling around and PV’ing an OGP SmartScope Flash or something related… though the feather probe, optical and laser measuring methods are neat.
Now wondering what the best priced gauge block sets are?
I wish people would stop pretending you will 3D print accurate or useful plastic toys to replace metrology tools that really aren’t that expensive.
I’m with Andrew- go buy a set of Mitutoyo calipers. They will actually be accurate to real numbers, not skip their position like every other digital caliper.
If you need to really make something, it’s an indispensable tool. Any 3D printer is going to cost more than a set of even 4″ Mitutoyos. InSize, and many cheapies I tried were just junk, lost their position, and skipped sizes. Dealing with that grief is simply not worth a couple more bucks to me.
I laughed at the video title, “Precision Calipers…”. Aside from the atrocious accuracy of a printed rack and pinion, the thermal coefficient of PLA is about 7 times that of steel. Even if the print was carefully adjusted to be somewhat accurate at 68f, just a few degrees temperature change is going to throw it out.
As a mental design exercise or toy, great. As a “precision” tool though, it’s a waste of time and money
Can’t go wrong with Mitu, Starrett, or Brown and Sharpe.
Definite points for the design and creativity. However I don’t think you can call it a “precision” tool when it’s made out of a material that isn’t dimensionally stable. I would like to know how the accuracy changes with the humidity on these scales, and over longer periods of time.
I only want mechanical vernier calipers. digital ones I easily recognize by the blank or flashing screen…
but then again, I live in a metric world, so reading calipers are easy.
Do you also like to count divisions on analog scope and develop negatives of their crt shots?
I can use from time to time dial calipers for their cool factor, but with 5 years of original Mitutoyo SR44 battery life I wouldn’t go back to mechanical one.
Someone has to make one of these out of brass!
>Clickspring entered the room<
Gears!
Tell me they do something.
http://www.harkavagrant.com/index.php?id=266
HARK, not funny at all !!
At least the article challenges my technical skills, not my intelligence.
As a machinist horologist, 1st cartoon captures my feelings on “steampunk” precisely.
I wish people would stop cannibalizing perfectly good watches and glueing their parts to goggles.