Why Jigs Are the Killer App for 3D Printing
By Inno Uncle
In manufacturing, jigs and fixtures are purpose-built tools that guide cutting, drilling, or assembly operations. They're expensive to machine and worth every penny because they guarantee repeatable accuracy. 3D printing changes the economics: a custom drill guide that would cost $200 to machine can be printed for $3 in filament and designed in an hour.
This is genuinely transformative for anyone who builds things — woodworkers, metalworkers, RC hobbyists, or anyone assembling products at home.
Corner Clamping Jigs for Glue-Ups
Woodworking corner clamps cost $20-40 each and you need at least four. Printed corner jigs — 90-degree brackets with slots for bar clamps — cost about $1 each in material and work just as well for cabinet carcasses and picture frames. Print them at 6 walls and 40% gyroid infill in PETG. The key design element is generous fillets at the internal corner to prevent stress concentration. I've used the same set of four for two years and they're still dead square.
Drill Guides That Lock In Accuracy
A printed drill guide with a steel bushing pressed into it gives you perfectly perpendicular holes every time. The bushing is the critical part — you can buy hardened steel drill bushings for a few dollars each, and pressing them into a printed block creates a tool that rivals commercial drill guides. Design the guide with registration features (edges that align with the workpiece) so it self-positions.
For repeated hole patterns — shelf pin holes, hardware mounting patterns — print a full template with bushing locations marked. It turns a 15-minute measuring job into a 30-second operation.
Assembly Fixtures for Production
If you assemble anything in quantity — even just making gifts for friends — assembly fixtures are force multipliers. I printed a fixture that holds six small boxes in alignment while epoxy cures, replacing the tedious process of clamping each one individually. The fixture has alignment pins that match holes in the box design, and the whole thing nests neatly for storage.
Radius and Profile Gauges
A printed set of radius gauges (convex and concave, 1mm to 25mm) takes about 200g of filament and replaces a $40 commercial set. Print them at 0.12mm layer height for smooth curves. Mark each gauge with raised text indicating its radius — much easier to read than engraved text, and you can feel it with your fingers.
Soldering and Electronics Jigs
A "third hand" soldering fixture with adjustable arms and PCB holders is a one-day print that beats commercial versions. Add silicone pads (cut from a cheap kitchen mat) to the gripping surfaces for heat resistance. Circuit board holders with spring-loaded clamps keep PCBs steady while you work. These are especially useful if you're building custom electronics for your 3D printer.
Material Selection for Tooling
PETG for anything that takes load or sees impact. PLA+ (not standard PLA) works for light-duty jigs. For drill guides, the printed body can be PLA but the bushing must be steel — plastic-on-steel will wallow out in a few uses. You can find quality PETG and PLA+ in our filament collection. For the build plate when printing large fixtures, a reliable PEI build plate ensures your long prints stay stuck down — nothing ruins a 14-hour fixture print like a corner lifting at hour 12.