I have a 2 wrench Bosch for about 12 years now.

I set the router on its side, engage the small inner
wrench and rest it against the workbench top, then
engage the outer nut and turn in the direction of
the inner wrench - the bench acts like a stop.

Easier than any other method I could figure. I must
be real smart since it "only" took me a year or so to figure
this out (after a few bruised knuckles).

Lou

In article , DIYGUY
wrote:

For the last 15 years I have always groaned when having to remove a bit
from my P-C 690 router. I always put one wrench in my left hand on the
bottom nut and the other wrench in my right hand on the collet nut. To
tighten was easy - simply squeeze the two wrenches together as if they
were pliers. Worked very well, but loosening was always a challenge
because I had to pull the two wrenches in opposite directions which
exercised muscles I used infrequently and really did not care to bulk up
on.

Lo and behold this weekend I made an amazing discovery. Simply reverse
the wrenches making the top wrench in my left hand and the bottom wrench
in my right and squeeze just as if I was tightening and the collet would
open like a dream. Where have I been and why was this not so obvious to
me?? Talk about a lack of brain power ...