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Adapters & couplers
Lampshade reducer ring, 40 mm to 28 mm fitting
A thin ring that lets a lampshade with a 40 mm European fitting sit on a lamp with a 28 mm bayonet holder, the perennial problem when shades and lamps come from different countries. The ring is 3 mm thick with a 28.5 mm central hole, a 45 mm outer diameter and a raised 1 mm lip at 40 mm that centres the shade. Because it sits near the bulb, print it in PETG or ASA and leave small vent gaps in the lip for airflow. Open the ready-made model free, resize it on your phone or computer, then download a print-ready STL, 3MF or G-code sliced for your printer, free.Opening the ready-made model and downloading it as STL or 3MF are free, no card; AI changes use credits, from Maker at $7.99 a month.No printer? We print this part and ship it to your door. See its priceUpdated
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Adjust
Change its numbers in the viewer for free, or ask the AI in the chat: wall thickness, hole size, the thing it clips onto. AI changes use 2 credits per request (1 for a quick edit, 3 for a redesign), paid with a plan from Maker at $7.99 a month.3Print
Download a watertight STL or 3MF free, with your numbers and hand edits, or G-code sliced for your printer at the same price. After an AI change the download is included in every plan (4 credits without one).
Dimensions of the ready-made model (editable)
| Parameter | Value |
|---|---|
| outer diameter of ring | 45 mm |
| central hole diameter | 28.5 mm |
| base disc thickness | 3 mm |
| centering lip diameter (centerline) | 40 mm |
| lip height above base | 1 mm |
| lip width (radial) | 1.5 mm |
| outer edge chamfer size | 0.5 mm |
| vent gap width (arc length in mm, approx) | 3 mm |
Example prompt
Create a lampshade reducer ring 45 mm outer diameter, 3 mm thick, with a 28.5 mm central hole. Raised centering lip 1 mm tall and 1.5 mm wide at 40 mm diameter with three 3 mm vent gaps. Chamfer the outer edge 0.5 mm.
Fit notes
Tell SpeakCAD the hole in your shade and the diameter of your lamp holder, and the ring is generated to bridge them exactly, no filing needed. Preview it in your browser and ask for a thicker version, a different lip height or a set of three for matching shades.
Questions people ask about a lampshade reducer ring, 40 mm to 28 mm fitting
A thin ring that lets a lampshade with a 40 mm European fitting sit on a lamp with a 28 mm bayonet holder, the perennial problem when shades and lamps come from different countries. The ring is 3 mm thick with a 28.5 mm central hole, a 45 mm outer diameter and a raised 1 mm lip at 40 mm that centres the shade. Because it sits near the bulb, print it in PETG or ASA and leave small vent gaps in the lip for airflow.
Click Open it free on this page and create a free account (no card): the ready-made model opens in your browser, on your phone or computer, nothing to install. Change its numbers in the viewer for free and download a watertight STL or 3MF free, or G-code sliced for your printer at the same price. An AI change in the chat uses 2 credits per request (3 for a redesign), and the download after it is included in every plan (4 credits without one). Start with Maker: 50 credits a month for $7.99, cancel anytime.
On this page: open the ready-made model free in a SpeakCAD account (no card), change any dimension in the viewer, then download the STL or 3MF free, or G-code sliced for your printer at the same price.
A shared STL is modelled for someone else's measurements. Here you open the ready-made model free, change it to your measurements in the viewer, then download a file sized for the part you actually own, free as STL or 3MF.
Yes. SpeakCAD slices the part on its servers with OrcaSlicer and your printer's official profile (380+ printers, including Bambu Lab, Prusa, Creality and Elegoo), and you download the G-code (a sliced .gcode.3mf for Bambu Lab printers). G-code sliced for your printer costs the same as the STL: included in every plan, free for a part you shaped by hand, 4 credits without a plan for a part with AI work in it. Pick your printer on the printers page to see its profile.
No. SpeakCAD runs in the browser on your phone or computer: the chat, the 3D engine and the live viewer load in the tab. The only file you download is the finished STL, 3MF or sliced G-code.
Print it your way
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