Bearings & Magnets

608ZZ bearings for spool holders and spinners, plus 606ZZ, 625-2RS and 683ZZ sizes, round neodymium magnets, and SS304 steel balls and dowel pins for the detents, hinges and alignment features in your printed mechanisms.
Skip to results list

Filters

9 products

Filter

Choosing 608ZZ bearings and motion hardware

Plastic rubbing on plastic wears and binds, so a few pieces of metal hardware make printed mechanisms smoother and longer lasting. Ball bearings carry rotating parts, polished pins act as axles and alignment features, steel balls create detents and rolling races, and magnets give lids and tool mounts a clean snap without any fasteners. Everything here is sold individually or in assortments, so you can design around standard sizes and buy only what the build needs.

Ball bearing sizes compared

BearingBore x outer x widthClosuresTypical uses
608ZZ Ball bearing8x22x7mmMetal shields both sidesFilament spool holders, fidget spinners, rollers on 8 mm rod or M8 bolts
606ZZ Ball bearing6x17x6mmMetal shields both sidesMid-size rollers, pulleys and pivots on 6 mm shafts
625-2RS Ball bearing5x16x5mmRubber seals both sidesIdlers and rollers on M5 bolts, especially in dusty spots
683ZZ Ball bearing3x7x3mmMetal shields both sidesCompact idlers and small mechanisms on M3 hardware

ZZ shields or 2RS seals?

The letters after the number describe how the bearing is closed. ZZ means a metal shield on each side that sits just clear of the inner ring, so the bearing spins freely with very little drag while blocking larger debris. 2RS means a rubber seal on each side that touches the inner ring: slightly more drag, but better at keeping out fine dust and moisture. Pick ZZ for free spinning parts and 2RS for grubby or damp locations.

Magnets and press fits

Printed hole sizes vary between printers, filaments and slicer settings, so no single figure suits everyone. The dependable method is a test print: model a small block with several pockets stepping up in small increments around the part's measured size, then use the pocket that gives the fit you want. Our article on tolerances and fit goes deeper.

  • Bearings: aim for a firm push fit and press on the outer ring only. An overly tight pocket squeezes the ring and makes the bearing drag.
  • Magnets: Small Round Neodymium Magnets come in 12 sizes from 3 x 2 to 15 x 2 mm, listed as diameter x height. Make the recess slightly larger than the diameter and fix the magnet with super glue or epoxy, or pause the print and drop it into an enclosed cavity.

Keep magnets, steel balls and small pins away from young children, as swallowed magnets and small parts can cause serious harm.

Steel balls and dowel pins

Stainless steel balls

The mirror finish SS304 steel balls come in 2, 3, 4, 5, 6, 8 and 10 mm. Run them in a printed race for turntables and lazy susans, pair a small ball with a printed spring or flexure for click detents on dials and sliders, or capture a larger ball in a posable joint. Make the pocket slightly smaller than the ball for a press fit, or add clearance and a smooth running surface where it needs to roll.

Dowel pins

Polished SS304 pins come in 2, 3 and 5 mm diameters, with lengths from 4 to 50 mm. Use them as hinge axles, as pivots in clamps and folding parts, or pressed into one half of a split print to line up the other half precisely. For a hinge, make the hole in the moving part slightly larger and the hole in the fixed part snug. See Print in Place Designs: Hinges, Joints, and Mechanisms for more ideas.

Buying bearings and magnets from OzFDM

Bearings, magnets, balls and pins are all sold individually, so a prototype needs only a handful and a batch build can scale up. The Stainless Steel Ball Assortment (100 pcs) and Stainless Dowel Pin Assortment (120 pcs) bundle the most useful sizes for less than buying each on its own. Orders over $299 ship free Australia-wide (excluding PO Boxes).

Bearings, magnets, balls and pins FAQs

Which bearing do I need for a filament spool holder?

Many printable spool holder designs use 608ZZ bearings, the same 8x22x7mm size found in fidget spinners. Check the model's notes for the bearing count and whether it runs on 8 mm rod or an M8 bolt. Shielded bearings suit spool holders well, because they turn freely with very little resistance.

How do I stop magnets falling out of a print?

Glue them in. A recess slightly larger than the magnet plus a drop of super glue or epoxy holds well, or pause the print to bury the magnet inside the part. Before glueing a pair, stick the two magnets together and mark the touching faces, so the finished parts attract rather than push apart.

What do the magnet sizes mean?

Sizes are listed as diameter x height. A 6 x 4 mm magnet is 6 mm across and 4 mm high, while a 15 x 2 mm magnet is a wide, thin disc. Measure the recess in the model you are printing, or check its design notes, and choose the size that matches.

What are the steel balls and dowel pins made from?

Both are SS304 stainless steel for good corrosion resistance. The balls have a mirror finish and the pins a polished finish, so each runs smoothly against printed plastic. The ball assortment holds 20 each of 3, 4, 5 and 6 mm plus 10 each of 8 and 10 mm, and the pin assortment has ten of each of twelve sizes.

Related