How to use it
- Pick your extrusion – 2020 or 2040, V-slot or T-slot.
- Print the clearance test strip first with the settings you will use. Lay a profile face-down and slide it on from the edge with the keys, one key at a time (1–5 notches = 0.2 mm tighter … 0.2 mm looser than your setting), and set the fit slider to the one that slides in snugly. Then do the same from the other edge with the short cover samples and set Cover grip to the one that pushes in firmly without cracking (1–5 notches = 0.10–0.30 mm).
- Choose a part and its options, then check the duty label and the print settings under the controls.
- Download the STL – it is already in the best print orientation. “All parts (ZIP)” gives you a full starter kit.
How the parts are made strong
- Brackets print on their side so the layers run round the corner, with a 3 mm inside fillet, optional 45° gussets and 5–6 walls.
- Locating keys drop into the slot so the bracket cannot twist, and the screw bosses are pointed (teardrop) so nothing overhangs past 45°.
- Snap arms taper from 2 mm to 1.2 mm and are long enough to stay inside the safe bending strain of the material you pick.
- Slot covers are a press fit, not a snap: the slot lip is too thin for a printed barb to flex behind it, so a crush rib on each side bites into the slot wall by the Cover grip you set (0.10–0.30 mm, default 0.15), whatever fit you choose. Push them in along the slot; PETG grips best.
- Duty is labelled light, medium or heavy relative to the other options – there are no load ratings, because printed strength depends on your printer and settings.
Recommended print settings
| Setting | Value |
|---|---|
| Material | PETG or ASA for frames; PLA for indoor prototypes; nylon for the toughest snaps |
| Layer height | 0.16–0.2 mm |
| Walls | 4 or more (5–6 for brackets) |
| Infill | 40–50% gyroid; 100% for clips and covers |
| Orientation | As downloaded |
| Supports | None |
Frequently asked questions
Which extrusions does this fit?
20 mm series 2020 and 2040 profiles with 6 mm slots – both V-slot (OpenBuilds style) and T-slot (Misumi/Bosch style 20 series) – plus, in beta, 3030 with an 8 mm slot and 4040 with a 10 mm slot (MISUMI HFS6 / HFS8 sizes, not yet print-tested). Brands differ by a few tenths of a millimetre, so print the clearance test strip first.
What does the fit slider do?
It is the gap left on each side between the printed part and the aluminium. 0.2 mm suits most well-tuned printers. Print the test strip: it has five keys from 0.2 mm tighter to 0.2 mm looser than your setting – use the one that slides in snugly.
Which screws and T-nuts do the brackets use?
M3, M4 or M5 screws into standard drop-in or roll-in T-nuts. Counterbored holes take socket-head cap screws; countersunk holes take flat-head screws. The holes sit on the slot centre line.
Can I print my own T-nuts?
Yes, for light loads: electronics, cable guides, panels. The drop-in T-nut goes in through the slot opening anywhere along the profile and turns 90° to lock behind the lips; the slide-in one goes in from the profile end. They take an M3 heat-set insert (strongest) or an M3/M4 screw that cuts its own thread. A steel hex nut cannot be captured in a 20-series slot – an M3 nut is wider than the opening and an M4 nut is taller than the space under the lip – and for frame joints steel T-nuts are still the right choice.
How does the print-in-place hinge work?
It prints standing up, already assembled: the knuckles meet on 45° cones with a small gap, which keeps them centred and the middle knuckle captive, and needs no pin and no supports. After printing, twist the leaves firmly once to break it free. It opens 180°. One leaf keys into the extrusion slot; the other screws to a panel or to a second extrusion. If it prints fused, raise the fit setting by 0.1 mm.
How strong are printed brackets?
Each part is labelled light, medium or heavy duty relative to the other options, not with a load rating – printed strength depends too much on the printer, material and settings. For anything where a failure could hurt someone, use metal brackets.
How do I choose the slot cover grip?
The clearance test strip has five short cover samples marked with 1–5 notches, gripping 0.10, 0.15, 0.20, 0.25 and 0.30 mm. Press each into a slot: pick the firmest one that goes in by hand without cracking or whitening. Softer materials (PETG, nylon) and slightly oversize slots like more grip; PLA usually wants 0.10–0.15 mm.
Do the parts need supports?
No. Every part is laid out in its best print orientation, with 45° chamfers, teardrop holes and pointed bosses instead of flat overhangs. The only bridge is the short roof of the rubber-pad pocket in the foot.
Why does the material matter?
Snap arms are sized to stay inside the safe bending strain of the material (PLA is the most brittle, nylon the most forgiving), and PETG, ABS/ASA and nylon get a little extra clearance because they shrink or string more.