Measure the drilled hole — 60 mm by default — and get the two pieces vendors sell as a grommet set: a flanged sleeve that presses into the hole and a cap that drops in flush with the flange, with a U-slot for the cables, a solid top or no cap at all. Set the sleeve depth to suit the desktop, then export STL to print or STEP for furniture CAD.
The real generator runs in your browser: set the parameters, then download STEP or STL. Nothing to install, no sign-up.
The first open downloads the CAD engine (about 20 MB).
Each parameter below rebuilds real geometry on every change — this is parametric CAD, not a scaled mesh.
| Parameter | Default | Range | What it does |
|---|---|---|---|
| Hole diameterHOLE_D | 60 mm | 30 – 100 | The drilled hole as measured, not the saw size. |
| Sleeve depthDEPTH | 16 mm | 8 – 45 | How far the sleeve reaches below the desktop; at most the desk thickness. |
| Rim overhangRIM | 6 mm | 3 – 15 | How far the flange laps past the hole on each side. |
| Fit clearanceCLEARANCE | 0.3 mm | 0 – 1 | How much smaller than the hole the sleeve comes out. |
| CapCAP | slot | slot / solid / none | With a cable slot, solid, or no cap. |
| Slot widthSLOT_WIDTH | 20 mm | 10 – 40 | At most two thirds of the hole; a third is typical. |
Every parameter can go in the page's link, so one link opens exactly the part you want. Example (50 mm hole, 17 mm cable slot):https://www.forgent3d.com/en/generators/desk-grommet-generator?HOLE_D=50&SLOT_WIDTH=17
Flange = hole + 12 mm (a 6 mm rim each side); the cable opening is the sleeve's bore, hole − 5.1 mm at the default clearance and 2.4 mm wall; slots are about a third of the hole, as on vendor caps. Each row opens the generator on that size.
| Hole Ø | Flange Ø | Opening Ø | Slot | |
|---|---|---|---|---|
| 35 | 47 | 29.9 | 12 | Open → |
| 50 | 62 | 44.9 | 17 | Open → |
| 53 | 65 | 47.9 | 18 | Open → |
| 60 | 72 | 54.9 | 20 | Open → |
| 63.5 | 75.5 | 58.4 | 21.5 | Open → |
| 80 | 92 | 74.9 | 27 | Open → |
35, 50, 60 and 80 mm are the common hole-saw sizes; Chinese listings name 50 mm most often, then 53 mm, and 63.5 mm (2½") is common on US office desks.
STEP AP214 in millimetres, exact B-rep — it opens directly in SolidWorks, Fusion, FreeCAD, Onshape or Inventor, and goes straight into a CNC quote form. STL for the slicer is one click too.
| This generator | Typical online STL generator | Vendor CAD library | |
|---|---|---|---|
| Any size within the range | Yes | Yes | Catalog sizes only |
| STEP with exact surfaces | Yes | Usually an STL mesh only | Yes |
| Changes the sliders don't cover | “AI edit” on the page | No | No |
| Account needed to download | No | Usually no | Often |
Every parameter is a link parameter; the link below opens the example part. ChatGPT, Claude or any assistant can write one like it from the parameter list (names, units, ranges) at: parameter list (JSON)
Example: https://www.forgent3d.com/en/generators/desk-grommet-generator?HOLE_D=50&SLOT_WIDTH=17
Press “AI edit” in the generator and say what to change — a keyway, holes, a different shape. The AI edits the part's model.py and it rebuilds in your browser, with undo. A few edits a day are free without signing in; to keep the result or go further, copy it into your models and continue with the AI agent.
Edit with AI →For bigger changes, several rounds, or a part you want to keep: copy it into your models (free account). The Forgent3D AI agent reads the model.py, edits it, rebuilds it and checks the result itself.
Copy and continue with the AI agent →The hole as measured. Saws cut a little oversize — one printed “70 mm” grommet turned out to fit a 65 mm hole — so put a caliper across the hole and enter that. The sleeve comes out 0.3 mm under it by default.
Makers aim 0.2–0.5 mm under the hole so the sleeve slides in without forcing; the default is 0.3. If it won't go in, raise the clearance by 0.1; if it falls out, lower it by 0.1. A hole that came out oversize can still be saved with a thin bead of sealant around the sleeve.
As the parts lie: the sleeve flange-down and the cap top-down, both without supports. PLA is what most printed grommets use; ABS or PETG give a slightly grippier press fit. Use some infill — around 15 % rather than 0 % — since the cap takes repeated pulls of cables.
Open https://www.forgent3d.com/en/generators/desk-grommet-generator?HOLE_D=50&SLOT_WIDTH=17 — a 49.7 mm sleeve for the 50 mm hole, a 62 mm flange and a cap with a 17 mm cable slot. Export STL to print it, or STEP for CAD.
Yes: CAP=solid gives a cap without a slot and DEPTH=25 makes the sleeve end flush with the underside — https://www.forgent3d.com/en/generators/desk-grommet-generator?CAP=solid&DEPTH=25. For any desk 16 mm or thicker the default 16 mm sleeve is enough; vendor grommets are made the same way.
Yes. Models you generate and the STL / STEP files you export are yours: print them, sell the prints, or use them in a product. No attribution to Forgent3D is required.
Already have your own .scad file? Convert OpenSCAD to STEP → · Preview it in the browser →
