On Mon, 18 Dec 2017 06:02:27 +0000, Richard Smith
wrote:

M16 bolt & nut takes 24mm spanner / socket...

I wanted to do some tests - micrometer etc. measure elastic and
plastic (permanently deformed) extension.

Was thinking 3/4inch drive (square) so wrench much stronger than bolt.

Want to keep wrench handle near horizontal, where bolt axis is
horizontal, so can haul on it.

Choice...?
Could get
* 12-facets (2 angles - 15deg increments) chromed hard socket
* 6-facets (1-angle - 30deg increments) tougher steel sockets.

The 6 facets impact wrench socket is the stronger / tougher
- but the 12 facets one is totally up to the job and gives twice as
many angles it can go on?

Any experience or experience on this and which is better choice?

As a retired auto mechanic, I can tell you that I shunned my 12pt
sockets early on in favor of the stronger 6pt sockets, mostly the
impact style so I could use them with air tools. If you induce any
angle during the test, the 12pt will strip the corners right off that
bolt head. A super-duty ratchet will make up the difference if you
need to get a bite at tighter angles.

Wear thick gloves and clear the area behind where you're testing. When
it lets loose, you need to pad where you'll fall. DAMHIKT

--
A sound mind in a sound body is a short but full
description of a happy state in this world.
--John Locke