What to measure
Rigid metric conduit sold as 20 mm is 20 mm on the outside, so the nominal size is usually right, but a caliper reading takes ten seconds and removes the doubt. Polyethylene irrigation pipe is softer and is delivered coiled: measure it in two directions and use the larger figure, because the clip has to pass the widest part of the oval. If the pipe will carry a push-on fitting next to the clip, measure the pipe itself and not the fitting.
Clearance, wall and material
The values here give a bore of 20.3 mm. That 0.3 mm clearance is the normal snap fit for PLA: the pipe clicks in and can still be slid along with a light push. In PETG drop to 0.2 mm if you want the pipe to stay where you put it. For a pipe that must move freely, such as a conduit that expands in the sun, go the other way and use 0.6 mm. The 2.4 mm wall is six passes of a 0.4 mm nozzle. Outdoors, PETG or ASA is the better choice: PLA goes soft at around 60 degrees C, a temperature a dark wall in direct sun can reach.
Printing
Print the clip on its side, resting on one C-shaped face, with the pipe axis pointing straight up from the bed. That puts the layers around the pipe, which is the direction the arms bend in. Supports are not needed. A 0.2 mm layer height is a good balance; at 0.3 mm the layer steps inside the bore start to grip the pipe unevenly. Three or four perimeters fill the 2.4 mm wall completely, so the infill setting hardly matters for this part.
Fixing it
The 16 mm tab has its 4.2 mm hole in the middle, 8 mm from the outside of the clip, which leaves room for a pan-head 4 mm screw and a screwdriver beside the pipe. If the pipe runs close to a corner and a tab on the right would not fit, set the number of tabs to 2 and use whichever side is reachable.
Outline drawing
Schematic, not to scale. The clip is 15 mm wide along the pipe and about 21 mm high.
Parameters the generator will use
| Setting | Link parameter | Value |
|---|---|---|
| Model | model | pipe_clip |
| Pipe diameter | diameter | 20 |
| Fit clearance | fit_clearance | 0.3 |
| Clip wall thickness | wall | 2.4 |
| Clip width along the pipe | width | 15 |
| Opening angle, degrees | opening | 100 |
| Screw tab length | tab_length | 16 |
| Screw tab thickness | tab_thickness | 3 |
| Screw hole diameter | screw_diameter | 4.2 |
| Number of screw tabs | tabs | 1 |
All lengths are in millimetres. Outer size from these values: about 41.1 x 15 x 21 mm.
Open the generator with these values
This model needs the $7 licence key: one payment, one key, and it opens all five paid models. Get a licence key on Gumroad ($7)
The pipe and cable clip needs a licence key: without one the generator shows the model locked, lists the values from this link and fills them in as soon as you unlock. The fitted drawer organiser bin is the free model and downloads with no key.