What is the proper screwdriver for a M2 counter-sunk hex screw?

Question

I have many M2 flush-mount, counter-sunk hex screws ordered from a variety of sources, including McMaster Carr, Ebay, etc. The Wiha 263 1.5x50 screwdriver I have does not drive any of these properly, which means I have to step down to a 1.3mm screwdriver which is too loose and causes stripping.

Can someone help me identify the proper screwdriver to drive M2 Hex screws? Numerous google searches don't seem to shed any light on this, although pages like this seem to suggest a 1.5mm hex driver SHOULD fit.

Carl Witthoft · Answer

A couple pages , csgnetwork and ruland specify 1.5 mm. Perhaps your Wiha is a bad unit, or perhaps you would be happier with a ball-end driver which is much easier to insert. At these sizes, it only takes a little bit of edge roughness to cause great difficulty inserting a flat-end driver.

Answered by Carl Witthoft on September 2, 2021

vidarlo · Answer

1.5mm would be the expected value for M2 hex. This can, however, vary between manufacturers - there may be legitimate reasons for deviating from standards.

The best thing would of course be to ask the manufacturer what driver size they recommend. The second best thing is to get a measurement. 1.5mm can be measured using calipers, perhaps aided by a magnifying glass.

Paul Jason Zofsak · Answer

.95mm would be what is used in the slot car industry for this

What is the proper screwdriver for a M2 counter-sunk hex screw?

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