Soldering a header onto a small board is a three-hand job done with two hands. You need one hand on the iron, one on the solder, and a third one you do not have to keep the board from spinning away the moment you touch it. The classic fix is a metal "helping hands" stand with crocodile clips. The cheaper, better fix is to print one.
A printed third hand is a heavy base with two or more friction-jointed arms sticking out of it. Each arm ends in a swappable tip, so the same stand can grip a bare PCB in soft printed jaws one minute and hold a wire with a standard crocodile clip the next. A design doing the rounds this week on Adafruit's weekly 3D printing roundup, shared by maker dymek34, takes that idea and offers it in two footprints: a compact base sized for a small 180 mm bed such as the A1 mini, and a larger one for full-size plates.
Two footprints matters more than it sounds. Bench tools are the one category where printing beats buying almost every time, because you can size the thing to your own bench, print a fresh tip when you snap one, and add a jaw shape for the odd connector nobody sells a clip for. The whole stand costs a few dozen grams of filament and an evening of unattended printing.
The build itself is straightforward. Print the base and arms at a 0.2 mm layer height with four perimeters, 30 to 40 percent infill in the base for stiffness, and about 15 percent in the arms. Reach for PETG, ASA or ABS rather than PLA for anything that ends up near the iron, since PLA starts to soften around 60 C and a hot tip brushing an arm will leave a dent. Joints are usually held by an M3 bolt and a captive nut, tightened until the arm holds its pose but still moves under gentle pressure. Before you cap the base, fill its cavity with coins, washers or sand: mass is what stops the stand chasing your board around the desk.
Try it on your printer. This is a perfect weekend print because nothing about it needs to be pretty, only accurate. Load a spool of tough filament, run a quick tolerance test on one joint, and print the arms overnight. If you need PETG or ASA that behaves predictably on a stock profile, browse the filament range at flarelab.com and pick a colour you will spot on a cluttered bench.
Frequently asked questions
Do I need supports to print a third hand?
Usually not. Most arm and base parts are designed to sit flat on the plate, and the jaws print in an orientation that keeps overhangs under 45 degrees. If your slicer flags a steep overhang, rotate the part before you add supports.
What filament should I use for a soldering helper?
PETG is the safest all-round pick because it shrugs off the warm air rising off an iron. ASA or ABS are better still for tips that sit close to the heat. PLA prints beautifully and is fine for the base and arms, but keep it away from direct contact with a hot tip.
How do I stop the base from sliding around the bench?
Give it mass. Most designs include a cavity you can fill with coins, steel washers, sand or lead shot before you cap it, and a few self-adhesive rubber feet on the underside stop the whole thing skating across a smooth desk.
Why won't my printed joints move?
Clearance. Moving joints need roughly 0.2 to 0.3 mm of gap, and an over-extruding printer closes that gap and welds the parts together. Dial in your flow rate, or scale the joint tolerance up slightly in your slicer before reprinting.
Spotted via Adafruit's #3DThursday 3D printing roundup, featuring a model shared by dymek34 on MakerWorld. Read the original post. Rewritten and expanded by Flarelab.
Originally published at flarelab.com.
