In article ,
says...
The (different) router I have came with both 12 & 12.7mm collets. It was
fitted with the 12 (cue swearing) until I realised they were different, not
just a spare. Has the 12.7mm been lost from the box? The 12mm is no use to
man or beast - never seen a bit that size in my life. Maybe worth a call to
the helpline if that's in the manual, should get a correct one sent out
right away.


Interesting. Your reply prompted a Google for "12mm collet"
Loads of links.
e.g.
Axminster Tools sell 8/10/12mm sizes AND 1/4"/1/2"
Trend sell an 1800w EURO router with a 12mm collet.

Looks as though we (with our old Colonies) may be out of line with our
new European partners because of our Imperial (no pun) sizing.
We convert 1/2" to 12.7mm, they never had 1/2" so they use 12mm.

As you suggest Toby, an A.M. call to JCB Customer Help. Might reveal a
Euro/UK packaging cockup and get me a new collet, £1000 compensation, and
a product recall by Argos. Looking forward to it

--
Mike