## How do I choose a bolt size for a nut?

Stretch the tape measure to the other side of the inner threads of the nut. Count the lines to find the diameter of the threaded hole. Measure across the widest opening the threads make. This measurement will help you match the thread diameter of the nut with the thread diameter of the bolt.

### How are nuts and bolts sized?

Bolts commonly use four types of measurement, while nuts use only two. Bolts are measured in length of shank, bolt head size, width of shank (the diameter of the threaded bolt body) and the thread pitch (the size of the thread). Nuts are measured by the width of the hex shape and by their thread pitch.

#### How do you determine bolt size?

How to Measure the Size of a Bolt

1. Step 1: Measure the shank’s diameter.
2. Step 2: Determine the thread pitch.
3. Step 3: Measure the length of the shank.
4. Step 4: Determine the bolt’s grade.
5. Step 5: Determine the shape of the bolt’s head.
6. Step 6: Measure the length of the threaded portion of the bolt.

What does M12 bolt mean?

M12x1. 75 is the measurement code that indicates the thread size and thread pitch of a screw. The first half (M12), is the size measurement (metric) taken across the outside diameter of the thread (which in this case is 12mm).

How do you read a nut size?

1. Read the first letter of the size. This the largest diameter: the measurement of the screw on the thread.
3. Read the third number, generally the one following the “x.”

## Does bolt size matter?

Normally it will not matter whether the bolt head or the nut is torqued. This assumes that the bolt head and nut face are of the same diameter and the the contact surfaces are the same (giving the same coefficient of friction). If they are not then it does matter.

### What is M8 bolt size?

Metric clearance and tapping drill hole sizes.

Size Clearance Hole mm Tapping Drill (std Pitch)
M5 5.5 4.2 mm
M6 6.5 5.0 mm
M8 9 6.75 mm
M10 11 8.5 mm