Every 3D printing hobbyist eventually ends up with a warped, scratched, or delaminated build plate sitting in a drawer. It is too damaged to print on and too useful-looking to throw away. A design shared by Sanja 3D on MakerWorld gives that dead plate a second career: it becomes the base of an adjustable magnetic PCB holder for soldering and repair work.
The idea is simple and it is why it works so well. Instead of building a clamp with hinges, screws and springs, the design uses small printed jaws with magnets embedded inside them. Drop the jaws onto a steel surface and they stay exactly where you put them, but slide freely when you push them. Any PCB, from a tiny sensor breakout to a full Raspberry Pi HAT, gets pinned between two jaws in about three seconds. There is no fixed maximum size, because the working area is whatever metal sheet you place underneath.
It is also a good example of remix culture in 3D printing. Sanja 3D built on an earlier PCB holder by squinn rather than starting over, and credits the original openly. That is how most of the best functional prints evolve: someone solves the hard geometry, someone else notices it could be magnetic, and the community gets a better tool than either would have made alone.
Printing it is beginner territory. Use PLA or PETG at 0.2 mm layer height with four walls and 25 to 30 percent infill, since the jaws take side loads rather than crushing forces. The important part is the magnet pockets. Most designs use 6 x 3 mm or 8 x 3 mm neodymium discs, so measure yours before slicing and check the model's stated size. Print a single jaw first as a test. If the magnet is loose, a drop of superglue fixes it; if it will not go in, scale the pocket up by 1 to 2 percent rather than forcing it and cracking the wall. Insert magnets with the same pole facing down on every jaw, or two jaws placed side by side will shove each other apart.
Try it on your printer. If your old plate is aluminium rather than steel it will not work, so grab any thin steel sheet, a magnetic knife strip, or a spare PEI-on-spring-steel plate instead. Print two jaws, live with them for a week, then print four more once you know the height you actually want. For more beginner-friendly 3D printing guides, filament tips and printable project ideas, visit Flarelab.
Frequently asked questions
What size magnets should I use for a 3D printed PCB holder?
Six by three millimetre or eight by three millimetre neodymium discs are the most common sizes in these designs. Always check the model page first, measure your magnets with calipers, and print one test jaw before committing to a full set.
Will this work on any old build plate?
Only if the plate is ferromagnetic. Spring steel PEI sheets and standard steel plates work perfectly. Aluminium, glass and most flexible plastic plates are not magnetic, so use a steel sheet or magnetic knife strip as the base instead.
Should I print PCB holder jaws in PLA or PETG?
PLA is fine for occasional bench use and prints more easily. Choose PETG if the holder will sit near a hot soldering iron or in a warm workshop, because PLA softens at roughly 60 degrees Celsius and can deform.
Why do my magnetic jaws push each other away?
The magnets were inserted with opposite poles facing down. Mark one face of every magnet before gluing and keep that face consistent across all jaws so they attract the base plate and stay neutral to each other.
Design by Sanja 3D on MakerWorld, remixed from an original by squinn. Spotted via Adafruit's #3DThursday. Rewritten and expanded for beginners by Flarelab.
Originally published at flarelab.com.
