MechanicalRebuild shelfUnplug and unscrew

Bearing and bushing

Also called ball bearing, sleeve bearing, roller.

Small ball bearings from printers, fans, skate wheels, and appliances. Fan bearings are usually the part that failed. Printer and scanner bearings are often fine. Hard-drive spindle bearings are fluid-dynamic and not a separable part you can press into a new design.

If you are new to this category

Rods, gears, belts, magnets, screws, and boxes. Printers are the best source of straight steel rod and toothed belts. Screws from a laptop are tiny and specific; a random screw in a laptop hole strips the plastic. Bag them by the machine they came from.

If two parts were meshing or riding together, keep them as a pair. A gear from one toy rarely fits a gear from another.

Inside a hard drive

The two curved blocks on the steel plates are the magnets, and they are the prize. Slide them apart. Do not pry straight up. The flat coil on the arm is a short-travel motor. The platters are not a useful material, and on some drives they are glass.

Specification. The right-hand column is what is typical. The label on the part in your hand wins if they disagree.
What to look for	Usual figure
Size	Measure bore, OD, and thickness. A 608 (8×22×7) is the skateboard bearing and shows up in a lot of hobbies.
Sleeve	Oil-impregnated bronze bushings in fans and motors. If they scream, they are done.

Volts are electrical pressure, amps are how much current is flowing, and ohms are how hard the part resists that flow. A higher voltage than the part was built for is how salvage parts die on the bench. If a cell in the table says “read the stamp”, that stamp is the whole specification.

What people actually use it for

A wheel
A shaft support
Replacing the same bearing

Leave this one when

Gritty when spun by hand, or rusty inside. Cleaning a sealed bearing rarely makes it new.

Buying a new one is the better idea when

A 608 or a 625 when you know the size you need. Bearings are a catalog item for a reason.

How to tell if this one still works

Spin. It should coast and sound like nothing. Side play should be small.

Tools you will want: Calipers.

Where people actually find it

2 notes, most useful first. “Leave it” means the part is in that machine and you should not take it: it is dangerous, worn out, or only useful if you already know that exact repair.

Harvest at a glance
From	Call	How many	How often	Where it sits
Clothes dryer	Worth it	2–4	usually	Drum rollers.
Hard disk drive	Leave it	1	always	Spindle.

Worth pullingClothes dryer2–4 · usually
In this particular machine
Plastic wheels with a bearing. They seize and squeal, which is often why the dryer was scrapped.
Where to look
Drum rollers.
How to get it out
Take only the ones that spin freely, as a pattern.
The condition to expect
Often the failure.
Leave it — present, not yours to reuseHard disk drive1 · always
In this particular machine
Fluid dynamic bearing. Not a 608 you can press out and reuse.
Where to look
Spindle.
How to get it out
Leave it.
The condition to expect
Not a catalog bearing.