Home Improvement : Acorns, Castles, Wings Are Some Kind of Nut

On the face of things, buying nuts looks like a pretty simple job. Just take the bolt you need the nut for down to the hardware store, find a nut that fits and buy it. In most cases, shopping for nuts is that easy.

There are, however, a few niceties. You may, for example, want a nut that absolutely, positively will not come off its bolt. If so, there are some specialized nuts for the job.

At the other extreme, you might want a nut that’s easy to remove by hand, without any tools. There are nuts for that kind of work, too. There are also nuts that secure other nuts, even nuts that protect you and your family. Let’s have a look:

Stay-Put Nuts

Probably the most common way to keep a nut in place is with a lock washer. Slip this under the nut, snug everything down tight and the washer bites into the nut, keeping it from coming loose.

Equally convenient are the liquid locking compounds such as Loctite or Liquid Lockwasher. These come in little plastic bottles or tubes. Put a drop on the threads, snug the nut down tight and the liquid cures into a glue that holds things together quite securely, yet still lets you undo your work with a wrench if you like.

But lock washers (both the solid and liquid variety) are not foolproof. In cases where you really need extra security, something more secure might be called for. Fo example the nut securing a lawn mower blade, or the wheel on a wagon.

Probably the most secure way to keep a nut in place is with a cotter pin. A nut secured with a cotter pin can’t come off unless the pin shears or falls out. To use a cotter pin, however, you need a special nut called a castle nut (because it looks like the turret of a castle). To use it, torque it into place, slip a cotter pin through one of the slots in the nut, and through the hole in the shank of the bolt.

Naturally you need a bolt with a hole in it. You can either buy a bolt with the hole already in place, or drill one yourself, as long as the bolt is not made of a special hardened-steel alloy.

An extra advantage of the cotter pin is that it will secure a nut even if the nut is not snugged down dead tight. This makes it good for bolted joints you want free to move or pivot. Examples of this kind of work might be simple wheel and axle joints, scissor joints and the like. In cases like these, turn the nut down snug, back it off a fraction of a turn, insert the pin and bend its ends over to lock it in place.

Another type of nut that does a good job of staying in place whether fully tightened or left loose is a fiber or plastic lock nut. This type of nut has a fiber or plastic ring or button set into the threads that creates enough friction to keep the nut in place under most conditions. It is not quite as secure as a castle nut and cotter pin, however.

Still another way to lock a nut in place is with a second nut called a jam nut. This is really just a thin version of a normal nut. In fact, you can use an ordinary nut if you like, if there’s enough space for it on the bolt.

In any case, just put your regular nut in place and tighten it down. Thread on the jam nut and finger tighten it down against the first one. Then, while holding the firstnut with a wrench, tighten the jam nut down against the first nut with another wrench. This will lock the first nut in place.

Easy-Off Nuts

For knockdown joints, or joints that need easy adjustability, wing nuts are the ticket. You can crank these down pretty tight by hand, but still get them loose in a flash without any tools. Somewhat neater, but with less leverage are cylindrical knurled nuts.

Safety Nuts

If you are putting together a child’s swing set, or fixing a toy fire truck, scooter or the like, acorn nuts are a good choice. These have domed heads that will cover the exposed ends of the bolts with a smooth, safe surface that won’t snag or tear clothing or skin.

To use an acorn nut, however, the bolt must be the right length. If it’s too long, its ends will bottom out against the dome of the nut before you get it tight. If you have a bolt that’s just a bit too long, however, you can slip a washer or two under the nut.

If the nut is too long for that trick, you can always cut it down with a hacksaw. This may deform the threads slightly, making it difficult to start the nut. To prevent this, I like to thread a conventional hex nut onto the bolt, past the cutoff point. Then I make the cut, and remove the nut. Removing the nut will reform any damaged threads, making it easy to screw the acorn nut into place.

The Right Nut Choosing the correct nut for the application you need is important. Here is what some of them look like. Castle Nut Acorn Nut Fiber Locknut Wing Nut