Gary Dean wrote:
I have just been reading a tool catalogue and came across an advert for this
device which the makers, Trend, claims to be the worlds fastest profile
scriber. It is basically a disk with a hole on the middle into which you
insert a pencil. You then, and I quote, "run the wheeled scribe along an
irregular feature and the pencil will accurately copy the profile directly
onto the work piece to be installed. It can then be cut and fitted resulting
in a perfect butt".

Anyone with only a rudimentary knowledge of geometry will know why this does
not work.

It's not really a Trend product, it's made by M.Power:
http://www.m-powertools.com/products...rfect-butt.htm

I have this product and it works really well in my view, excellent for
trim carpentry.
It comes with three disks of different diameters, and an aluminium shaft
whit a spring loaded pencil inside.
Very handy when you hold a piece of wood against the wall with one hand,
and scribe with the other hand.


JES