The best hand tool sockets in the world

Rarely do I try to play the best or worst game. However, objectively there is reasoning behind this post.

Sockets, like many other tools, are manufactured to standards. The standard for hand tool sockets is ISO 691:2005; this standard designates the tolerance range for class 1 and class 2 sockets:

First grade tool makers such as Snap on, Mac tools, Matco, SK, Hazet, Stahlwille and many others manufacture to class 1 tolerances. Second line tool makers such as Craftsman, Stanley tools, Husky tools, Harbor Freight and many other manufacture to class 2 tolerances.

Objectively, therefore, from a snugness perspective, there isnt much of a difference within class 1 makers; the same way there isn’t that much of a difference between class 2 makers.

Bolt tolerances for which sockets are used on are made to standards ISO 4759 and DIN 564: 1995-02:

For example therefore, for a 13mm bolt and socket under tolerance class 1 conditions will have a gap at minimum of 0.04mm and a maximum of 0.51mm. Real world the gap is normally somewhere in between.

So, how could one socket maker be any better than another if they all work to a socket standard?

Well, Koken tools of Japan, a socketry tool maker has chosen for their ‘Zeal’ line of socketry to work to tighter than ISO standard tolerances.


Objectively this has been measured to be true in this thread:

Koken has shown to be the tightest of all measured sockets, and unsurprisingly other makers are making their tools to the tolerances they have committed to as per the ISO standards.

So the next time you look at that rusty or rounded bolt, consider tolerance classes, and consider if it may be worth getting some Koken Zeal sockets.

Be the first to comment

Leave a Reply

Your email address will not be published.