Non Preferred Sizes

Wednesday 25th October 2017

All fastener standards have specific sizes which are commonly used.

However, from time to time, non preferred sizes come into play.

When the original fastener sizes were being standardised it became necessary to reduce the number of available diameters that one could use. For example when using an M8 or an M10 nut, whats the point of having an M9 nut? It's only a little bit bigger than an M8 - so why not just use an M10 nut. In this way, M8 and M10 became preferred sizes and the M9 became a non-preferred size.

This has the consequence that you need to keep a smaller number of spanners in your toolkit, and as anyone will tell you, having fewer spanners to get a job done is a more efficient and less frustrating way of working on a job.

However, some manufacturers still seek an M9x1.25 nut for their job - some automotive manufacturers used these fasteners to make it more difficult for after market parts to be made.

Presently, Trojan special fasteners can make a number of non-preferred metric, whitworth and unified sizes. Just to give you an example, we can make:
M7, M9, M11, M13, M14, M15, M17, M18, M19, M21, M22, M23, M25, M26, M27, M28, M32, M33, M34, M35, M36, M37, M39, M40, M43, M44, M45, M50 and M52 in various pitches both normal and left hand thread forms.

If you're looking for a nut in a strange diameter and pitch combination, just give us a call and we'll do our best to make it for you.