3D Printer

A 3D printer builds a part by laying down melted plastic in thin layers, following a digital file instead of a pencil line. The desktop kind nearly everyone means -- FDM, for fused deposition modeling -- pushes a filament of plastic through a hot nozzle onto a moving bed, one layer at a time. You send it a model, it runs for anywhere between twenty minutes and a full day, and you come back to a part.

That is genuinely the whole of the theory, and it is the least interesting thing about owning one in a woodshop.

Why it earns bench space

Not for printing projects. Wood is a better material than plastic for essentially anything you'd want to make out of wood, and a printed box will always look like a printed box. What a printer is for is the thing that helps you make the thing -- the jig, the adapter, the holder, the stop. It sits in the same family as a CNC router: a machine that turns a file into a physical object. The difference is that the CNC makes your actual work, and the printer makes the tooling around it.

The honest test of whether it's worth the bench space isn't "what can I print?" It's how often you've hacked something together out of scrap plywood because the real part doesn't exist, costs more than the tool it fits, or ships in three weeks.

Dust collection, which it quietly solves outright

This is the one that converts people. Every manufacturer has settled on a slightly different port diameter, none of them match your extractor, and the official adapter either doesn't exist or costs more than the hose. A printed stepped adapter takes an hour of machine time and fits exactly, because you measured both ends yourself. Once you've made one you will make nine more, and your dust collection will stop being a system of duct tape and hope.

Jigs, in the size you actually need

A shop-made jig is usually a compromise between the tolerance you want and what you can cut from offcuts in twenty minutes. A printed one holds whatever tolerance you asked for, repeats exactly if you break it, and can have features -- captured nuts, indexed holes, a curve that would be tedious to cut -- that are simply awkward in wood. Center-finders, drilling guides, corner-assembly squares, angle setters, circle jigs and router template blanks all print well.

Shop organization on demand

The other half of the value is storage that fits the thing rather than the other way round. Gridfinity -- a standard grid of stackable bins and baseplates -- is the usual route, and it means a drawer insert sized to exactly the bit set you own, not the one the case manufacturer imagined. There's a Gridfinity generator on this site that will size bins and plates for you, and a list of models worth printing that other people have already designed.

What it is bad at, honestly

• Sustained load. PLA creeps -- hold it under constant pressure and it slowly deforms. Fine for a jig you clamp for a minute, wrong for anything that stays loaded.
• Heat. PLA starts softening around 140 °F / 60 °C. A part left on a sunny windowsill or in a car in July will sag; anything near a motor housing wants a better plastic.
• Blades and bits. Plastic is not a sacrificial fence. A router bit will find it, and the result is a spray of molten filament and a ruined part.
• Size. Most desktop beds top out around 10 in / 250 mm square. Bigger means printing in pieces and gluing them.

Materials worth knowing

PLA is stiff, dimensionally accurate, cheap and easy, and it's the right default for most shop jigs. PETG is tougher and takes heat better -- worth it for anything that gets clamped, dropped, or lives near a motor. ASA or ABS for anything going outside, since PLA degrades in UV. Nobody needs to go further than that for shop use, and most of what a woodworker prints will be PLA for the rest of time.