10 Rules for Using Sockets and Ratchets Properly

Most rounded fasteners and most broken sockets come from three mistakes: the wrong drive size for the torque being applied, a socket that nearly fits instead of one that does, and reaching for leverage instead of a bigger tool. Get those three right and the rest is maintenance. The rules below are the ones that matter on a working vehicle, in the order you meet them: choose the drive, choose the socket, work out which way the thread runs, and know what to do when a fastener will not move.

Which drive size should you be using?

Match the drive to the torque, not to what is nearest. The larger the drive, the more torque the square can carry, which is why a stubborn or over-tightened fastener wants a bigger drive rather than a longer pull on a small one. The reverse is just as important: a 1/2 inch drive breaker on a small bracket bolt gives you far more torque than the fastener can take, and the fastener is what gives. Ranges overlap, so treat the table as a guide rather than a boundary.

Does the exact socket fit really matter?

It matters more than anything else on this list. A socket that is fractionally oversize contacts the fastener on a smaller area than it was designed to, and the corners of the hex carry a load they were never meant to carry. The head rounds, and once it has rounded the job gets considerably longer. The classic near-misses are between systems, where imperial and metric sizes land within a few tenths of a millimeter of each other. A 10 mm socket drops onto a 3/8 inch head with close to half a millimeter of slop, and a 9/16 inch socket goes onto a 14 mm nut with roughly a quarter of a millimeter. Both feel like a fit and both will round a tight fastener. Check the marking rather than the feel, and keep metric and imperial sockets in separate trays so the wrong one is never the closest one. Fit matters at the drive end too. A worn ratchet square or a loose extension lets the socket rock under load, which puts the same uneven stress into the fastener. Sets that keep sizes in a fixed order, like those in the socket sets range, make the right size the easy one to reach for.

Six point or twelve point?

A six point socket contacts the flats of the fastener and is the right choice on anything tight, corroded or already slightly rounded, because the load goes into the flat rather than the corner. A twelve point engages every 30 degrees instead of every 60, which is what you want in a confined space where the ratchet has almost no swing, and on twelve point fastener heads themselves. The rule is simple: twelve point for access, six point for torque. If a fastener is fighting you, change to six point before you change to a longer bar.

When do you need impact sockets?

Whenever an impact tool is involved, without exception. Chrome sockets are made and heat treated for smoothly applied load; they are harder, more brittle, and under the hammering of an impact gun they can crack and throw pieces. Impact sockets are made from a tougher, more ductile alloy with thicker walls and the familiar dark finish, and they are designed to absorb that shock. Use them with impact wrenches, air ratchets and impact drivers, and use matching impact extensions and adaptors too, since the accessory is just as likely to fail. Everything rated for that duty is in the impact sockets range. The rule does not run the other way: an impact socket on a hand ratchet is fine, just bulkier.

What should you never do to free a stuck fastener?

When a fastener will not turn, something is going to give first, and your job is to make sure it is the rust rather than the tool or the head. Before applying more force, check you are turning the correct way: left-hand threads still appear on some wheel assemblies, driveline components and rotating machinery, and a fastener that will not move may simply be one you are tightening. Then choose a more capable tool rather than more leverage.

• Do not slip a scaffold pole or tube over the handle. It is dangerous, and the ratchet mechanism or the drive square usually breaks before the fastener moves.
• Do not fit a socket and then use the vehicle itself to turn it. It is uncontrollable, and the tool will break.
• Do use a larger drive, a breaker bar, or an impact wrench with impact sockets.
• Do give penetrating oil time to work, and shock the fastener rather than leaning on it steadily.

How should sockets and ratchets be looked after?

Clean and dry before they go back in the drawer, every time. Water and road salt left on a socket overnight will start corrosion, and corrosion inside a ratchet head is what turns a crisp mechanism into a slipping one. Keep the ratchet mechanism working with a light oil, applied sparingly. Heavy oils and greases feel like better protection but they collect grit, and grit in a pawl is exactly what makes a ratchet skip under load, usually with your knuckles in the way. Check drive squares and retaining balls for wear when you clean, and retire anything cracked or deformed rather than leaving it for someone else to find. Replacements and accessories are in the sockets and accessories range.

The ten rules, in short

1. Match the drive size to the torque, not to whatever is nearest.
2. Use the exact socket size. Nearly right is what rounds a head.
3. Six point for torque, twelve point for access.
4. Keep metric and imperial apart so the wrong one is never closest.
5. Impact tools take impact sockets and impact accessories, always.
6. Check the thread direction before you decide a fastener is seized.
7. The weakest point gives first, so make sure it is the rust.
8. No bars or poles on the handle for extra leverage.
9. Never use the vehicle itself to turn a socket.
10. Clean and dry before storage, and a light oil in the ratchet, never grease.