How to choose the correct bolt length

The principle for calculating the correct bolt length is simple:Once everything has been assembled, the bolt should protrude at least one millimetre from the nut.

The minimum permitted bolt length is therefore the total thickness of everything assembled: plate + nut length + one additional millimetre.

Calculation example: Drawbeam 10 mm + endplate 10 mm + spacer 8 mm + bracket 6 mm + nut 20 mm + one protruding millimetre = minimum bolt length 55 mm.

The maximum length of the unthreaded section of the bolt must equal the plate thickness minus two millimetres (in order to ensure that the entire nut encapsulates the bolt threads).

Calculation example: Drawbeam 10 mm + endplate 10 mm + spacer 8 mm + bracket 6 mm - 2 mm = maximum permissible unthreaded section 32 mm.

In this case, you need to select a bolt that is at least 55 mm long, with an unthreaded section measuring 32 mm or less.

What is the material thickness?

The precise material thickness can be found in the information drawing or installation instructions of each product. The thicknesses of our most common products can be found in the table below.