Embedding Magnets in 3D Prints: Hole Tolerances, Press-Fit and Pause-at-Height

September 28, 2026

Small round neodymium magnets for embedding in 3D printed parts

Written by Logan F.

Quick answer: Glue magnets into a pocket modelled about 0.2 mm wider than the magnet, press-fit them into a hole about 0.1 mm wider, or seal them inside with a pause at height. Printed holes usually come out slightly small, so treat these as starting points and print a test gauge. Mark polarity before inserting anything.

Small neodymium magnets turn printed parts into lids that snap shut, tool holders that swap in a second, and signage that sticks to steel racking. Getting them in is mostly about hole size and orientation. Our small round neodymium magnets are listed as diameter × height, so a 6 × 3 mm magnet is 6 mm across and 3 mm tall. This guide covers the three ways to fit them, starting hole sizes for every size we list, pause-at-height steps in Bambu Studio, OrcaSlicer and PrusaSlicer, and how to get polarity right first time.

Three ways to fit a magnet

Method	How it holds	Magnet face	Best for
Glued in a pocket	CA (super glue) or epoxy in a slightly loose pocket	Exposed, can sit flush	Fridge magnets, lids, parts where the magnet must touch its partner
Press-fit	Friction in a hole close to magnet size	Exposed	Quick assembly with no glue, parts you might rework
Captured with a pause	Sealed under printed layers	Hidden under plastic	Parts that are handled a lot, where a magnet must never fall out

Our product page suggests gluing with super glue or epoxy, or a compliant press fit, for magnets in parts that are handled often. A captured magnet cannot work loose at all, but the plastic skin over it adds a small gap, so the pull between two parts is a little weaker than magnet-to-magnet contact.

Starting hole sizes for each magnet

Printed holes almost always come out smaller than the CAD model. In CNC Kitchen's heat-set insert tests, a hole had to be modelled at 4.1 mm to print at 4.0 mm in PLA (see Threaded Inserts for 3D Prints: Cheap vs Expensive). Our own tolerances guide covers why. The sizes below build in that shrink. They are starting points to test on your printer and filament, not guaranteed fits.

Magnet (D × H)	Glue-in pocket (dia × depth)	Press-fit hole (dia × depth)	Captured pocket (dia × depth)
3 × 2 mm	3.2 × 2.1 mm	3.1 × 2.1 mm	3.3 × 2.2 mm
5 × 3 mm	5.2 × 3.1 mm	5.1 × 3.1 mm	5.3 × 3.2 mm
6 × 2 mm	6.2 × 2.1 mm	6.1 × 2.1 mm	6.3 × 2.2 mm
6 × 3 mm	6.2 × 3.1 mm	6.1 × 3.1 mm	6.3 × 3.2 mm
6 × 4 mm	6.2 × 4.1 mm	6.1 × 4.1 mm	6.3 × 4.2 mm
8 × 2 mm	8.2 × 2.1 mm	8.1 × 2.1 mm	8.3 × 2.2 mm
8 × 3 mm	8.2 × 3.1 mm	8.1 × 3.1 mm	8.3 × 3.2 mm
10 × 2 mm	10.2 × 2.1 mm	10.1 × 2.1 mm	10.3 × 2.2 mm
10 × 3 mm	10.2 × 3.1 mm	10.1 × 3.1 mm	10.3 × 3.2 mm
12 × 2 mm	12.2 × 2.1 mm	12.1 × 2.1 mm	12.3 × 2.2 mm
12 × 3 mm	12.2 × 3.1 mm	12.1 × 3.1 mm	12.3 × 3.2 mm
15 × 2 mm	15.2 × 2.1 mm	15.1 × 2.1 mm	15.3 × 2.2 mm

Before you commit a big print, measure a few magnets with calipers and print a tolerance gauge. The free Magnet Press-Fit Tolerance Gauge on MakerWorld steps a hole up in small increments to +0.5 mm so you can find the fit you like. Note the winning offset alongside your printer and filament, and reuse it.

Orientation matters

Where you can, orient the part so each pocket's axis is vertical on the build plate, opening upwards or sealed inside. A round hole printed with its axis vertical is drawn as a circle in every layer. A hole printed on its side is built from stacked layers and the top droops, so it comes out undersized and oval.

Press-fitting magnets

Add a small chamfer at the hole entry so the magnet starts straight.
Press with a flat tool, a clamp or a vice, not a hammer. Neodymium magnets are brittle, and Wikipedia's neodymium magnet article notes they can chip and shatter when they strike each other.
If the fit is too tight, try thin crush ribs inside the hole instead of opening the whole diameter. The ribs deform while the rest of the wall stays supported.
Never push a magnet in with a soldering iron the way you would a heat-set insert. Standard N-grade neodymium magnets have a maximum operating temperature of about 80°C, and they lose strength when overheated.

Gluing magnets in

Use CA glue for speed or epoxy for extra hold, as our product page suggests.
Put a small drop in the pocket, not on the magnet, so glue does not end up on the face or your fingers.
Press the magnet down flush with a flat non-magnetic tool, such as a wooden or plastic stick. A steel screwdriver will simply lift the magnet back out.
Let the glue cure fully before testing the joint. Magnets pulling on wet glue can drag themselves out of the pocket.

Capturing magnets with a pause at height

Design a closed pocket inside the part with the captured sizes from the table, and leave at least a few layers of plastic above it. Slice, then find the first layer that starts to cover the pocket. The pause goes on that layer, so the printer stops with the pocket still open.

Bambu Studio

In the Preview tab, drag the layer slider to the first covering layer, right-click the + next to the slider and choose Add Pause. The Bambu Lab wiki confirms the printer stops before printing that layer.

OrcaSlicer

OrcaSlicer works the same way from the layer slider in its preview. It inserts the Pause G-code set in your printer profile, so check that field is filled in under the machine G-code settings described in the OrcaSlicer wiki.

PrusaSlicer

Right-click the + on the layer slider in Preview and add a pause. Prusa's article on inserting a pause or custom G-code at a layer explains that the pause is inserted before the selected layer prints, and that pauses do not work with sequential printing.

Pause-at-height tips

Scrub through the layer preview and confirm the pocket is still open on the paused layer.
Push every magnet fully to the bottom. A magnet standing proud will be struck by the nozzle when printing resumes.
Hardened steel nozzles are steel, which attracts magnets. A loose magnet can jump up to the nozzle as it passes, so seat magnets firmly or add a tiny drop of CA before resuming.
Our product page advises against printing directly onto magnets. The extra 0.2 mm of depth in the captured pocket keeps the nozzle and fresh plastic off the magnet face.
Have your magnets sorted and polarity-marked before the pause, so the bed is not left waiting and the part does not cool more than it needs to.
Keep your magnet stash off the printer. Strong magnets can disturb the magnetic base under a flexible build plate.

The same pause technique is used for manual colour changes, covered in Multicolour Prints Without an AMS.

Getting polarity right

Two magnetised parts only attract if opposite poles face each other. A single magnet fitted upside down turns a lid that snaps shut into one that pushes itself away.

Keep magnets in a stack and draw a marker line on the top face of the stack before you separate them. Our product page recommends marking one pole.
Make a reference magnet with a marked face, and test each magnet against it before it goes in.
For parts that should only fit one way, alternate polarity across the magnets, for example north, south, north, south along a lid. The lid will then repel if it is flipped.
Skip polarity entirely by pairing a magnet with plain steel. Our galvanised steel square nuts are steel and make neat strike plates in a square pocket. SS304 stainless washers, pins and balls will not work well: austenitic stainless steel such as 304 is usually non-magnetic.

Magnet safety

Keep loose magnets away from children and pets. The ACCC warns that swallowing more than one magnet can cause serious internal injuries or death, and Australia bans small high-powered magnets supplied as toys, games, puzzles, construction kits and certain jewellery. If you plan to give or sell a printed item containing magnets, check the ACCC rules first.
Magnets can pinch skin when they snap together. Slide magnets apart sideways rather than prising them.
Store magnets away from phones, bank cards, memory cards and other electronics, as our product page advises.

Shop the materials in this guide

Small Round Neodymium Magnets: 12 sizes from 3 × 2 mm to 15 × 2 mm, sold individually, with 10% off 100+ and 20% off 200+
Bearings and Magnets: magnets alongside bearings, stainless pins and balls for moving parts
Galvanised Steel Square Nuts: steel strike plates for a magnet without a second magnet
3D Print Finishing Tool Kit: hobby knife and files to clean up pocket edges

Frequently asked questions

How much bigger than the magnet should the hole be?

As a starting point, model a glue-in pocket about 0.2 mm wider than the magnet, a press-fit hole about 0.1 mm wider, and a captured pocket about 0.3 mm wider and 0.2 mm deeper. Printers and filaments vary, so confirm with a test gauge.

Will printing over magnets weaken them?

Standard N-grade neodymium magnets are rated to about 80°C for continuous use and lose strength when overheated. Keep the nozzle and fresh plastic off the magnet face with a slightly deeper pocket, and never heat magnets in with a soldering iron.

What glue works best?

CA glue is quick and fine for most parts. Epoxy gives extra hold for parts that take knocks or are handled constantly.

Is there bulk pricing on magnets?

Yes. Any 100 or more magnets get 10% off and any 200 or more get 20% off, applied across sizes. Orders of 300 or more can only be shipped by road freight.