3D Printing Parts for a Fancy Micrometer
The Digit Mike
Brown and Sharpe Digit Mike’s are beautiful, Swiss-made micrometers with a fully mechanical digital display which direct reads to 0.0002.”
Unfortunately, there is a systemic manufacturing problem with a cylindrical plastic key on the spindle. These are almost always cracked.
Try searching for Digit Mike on eBay, and you’ll see what I mean.
Project
My goal for this project was to 3D print a replacement key for this part, and to make the part and the design available for anyone else that wanted to do the same.
MSLA is the perfect 3D printing technology for this application, combining high resolution with accuracy to reproduce the geometry of the part.
Simply machining a replacement isn’t easily done because of two internal keys.
The Printing
I have an Elegoo Mars 2 Pro MSLA printer, but I hadn’t used it before this project.
Setting up the printer is easy, and many have shown that online.
I followed Clough42’s instructions after observing that he had some success with it.
I used a CAD program to replicate most of the features on the original Brown and Sharpe part, and decided to test print it to fit on an actual micrometer spindle. This key is fundamental to the accuracy of the micrometer, and a perfect fit is essential.
After achieving a successful fit with the default resin, I worked on ganging them up.
This worked pretty well, but printing directly on the bed created and elephant’s foot defect due to the long first layer exposure.
Also, they were the wrong color.
That’s better!
These press over a boss on the spindle, shown here.
Result
I think the result is pretty nice looking, and the fit is perfect.
I have been using the keys printed here on a micrometer for over a year now, and haven’t experienced any problems with it.
Availability
The Keys are available on eBay, for a price. Maybe one day I’ll make up the cost of the Elegoo printer with these parts.
I am also making the STL available for these, if you happen to have a MSLA printer and would like to give it a try.
All parts were printed in Elegoo Standard Black.