Guides

How to measure a screw and work out its metric size

Measure any small screw with a caliper or a ruler and turn it into a metric size like M2 x 4 mm. Includes a pitch table, length rules by head type and the mistakes that cost people money.

Removing a stripped tiny screw without wrecking the device

Practical ways to get out a stripped M1.6, M2 or M2.5 screw in a laptop, phone or camera — rubber band trick, cutting a slot, screw extractors and when to drill.

Laptop screw sizes explained

Which metric screws laptops actually use, where each size lives inside the machine, why bottom-case screws vary in length, and how to replace a lost one safely.

Metric vs imperial screws — the sizes that fool everyone

M2.5 vs #4-40, M3 vs #5-40, M4 vs #8-32, M6 vs 1/4-20. Which pairs are close enough to start threading, what happens when you force them, and how to tell them apart.

Thread locker and torque on small screws

How tight is tight enough for M1.6 to M6 screws, when to use blue threadlocker, and why plastic bosses need a fraction of the torque metal does.

Screw head shapes and when each one is right

Pan, button, countersunk, flat, cheese, socket cap, wafer and low-profile heads compared — height, bearing surface, and which one your device actually needs.

Putting screws into plastic without stripping it

How to get a screw to hold in plastic: boss sizing, pilot holes, thread-forming screws, heat-set brass inserts and how many times a plastic thread can be reused.

Choosing the right screw length

How long should a screw be? Minimum thread engagement by material, why a screw 1 mm too long can wreck a laptop, and the safe way to shorten one.

Which screw material to use, and what rusts

Stainless A2 vs A4, zinc plated steel, black oxide, brass, titanium and nylon compared for strength, rust resistance, magnetism and price — plus galvanic corrosion between metals.

Security screws and how to get them out

Torx security, pentalobe, tri-wing, spanner, one-way, clutch and Torq-set heads identified, plus the bits that fit and legal ways to remove them when you have no bit.

Keeping track of tiny screws during a repair

Magnetic mats, screw trays, tape maps and labelling systems for device repair, so every screw goes back in the hole it came out of.

Cross-threaded, seized and spinning screws

Why a screw goes in crooked or locks solid, how to back it out without destroying the hole, and how to repair a damaged thread with a tap, insert or bigger screw.

Washers, locking methods and screws that will not stay tight

Plain, spring, serrated, wave, nyloc and wedge locking washers compared, plus which methods actually survive vibration and which ones people only think work.

How to buy the right screws online

How to read a screw listing, what an assortment kit is actually worth, spotting soft low-grade screws, and the details listings leave out that cause returns.

Opening a laptop, phone or console without damage

A safe order of operations for opening a sealed device: hidden screws, adhesive, plastic clips, ribbon cables and battery isolation, plus the tools that do less damage.

Screw standards: ISO, DIN, ANSI and JIS

What DIN 912, ISO 4762, DIN 965, ISO 7380 and similar codes actually mean, how DIN maps to ISO, and why a JIS driver is not a Phillips.

Identifying a screw when the manufacturer never published the size

Most cheap appliances, cars and tools never publish screw sizes. Here is the practical order of attack to identify a screw yourself, using a caliper, a nut, a tap or the hole itself.

Choosing and fitting screws in 3D printed parts

Hole sizes, heat-set insert dimensions, self-tapping into plastic and how to stop printed parts splitting. Practical numbers for M2 to M6 in PLA, PETG and ABS.

Eyeglass, watch and hearing aid screws

The smallest screws in daily life. What sizes glasses hinges, watch cases and hearing aids actually use, how to measure them, and how to stop them falling out again.

License plate, trim and small automotive screws

What size screws hold a license plate, interior trim and small vehicle fittings, why they rust solid, and how to replace them without stripping the mount.