From Team 449 Wiki

A bolt is used in combination with a nut to hold things together. A hole is drilled through the piece, and the bolt is run through the hole. A connector (a bracket or gusset) is placed on the other side, and a nut is screwed onto the end holds the piece and connector together. The connector is bolted to the other piece to join in the same way, so the pieces are held together via the connector.

Naming conventions

In the US

American bolts sizes are specified in the form of <diameter>-(threads per inch>. For diameters of 1/4" and larger, the size is simply the diameter in inches, e.g. 1/4-20. For diameters smaller than 1/4", the diameter is the industry numeric size number. Larger numbers are larger diameters, but they do not correspond to any units. If a bolt specification starts with a # character, it is an industry numeric size. If it doesn't, you will have to use context. For example, 10-32 does not refer to a 10-inch-diameter bolt, but a #10 diameter bolt. Sometimes, "x<length in inches>" is appended to the end.

In metric

The rest of the world uses the metric system, which, as usual, is simpler and easier to understand. Metric bolts are specified in the form of M<diameter in mm>-<thread pitch>, e.g. M3-0.5. Thread pitch is the distance between adjacent threads. As with American bolts, "x<length in mm>" can also be appended to the end.

Types of bolts

Type Diameter (in) Notes
1/4-20 0.25 The most common bolt, as our team has a lot of them and they are used with 80/20. They should not be used when 10-32s can be used, as they are much heavier, and the extra strength is often unnecessary.
10-32 0.19 Lighter than 1/4-20s, and usually strong enough. Use these when you can.
8-32 0.164 Mostly used to mount things.


When bolting material that might deform under the force of the tightened bolt, it is good practice to use a washer to distribute the load and prevent deformation.

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