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.

This tool costs £23.95 in UK, I guess thats about $40 in the US. Trend make
excellent routers, trust me, I have one, I cannot believe that Trend, a
company I am sure you will know in US, could possibly have got this wrong,
so please guys tell me what I am missing.

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.

This tool costs £23.95 in UK, I guess thats about $40 in the US. Trendmake
excellent routers, trust me, I have one, I cannot believe that Trend, a
company I am sure you will know in US, could possibly have got this wrong,
so please guys tell me what I am missing.

I don't follow you on why it would not work. If the wheel follows the
surface and fits around the pencil, then the pencil would be held
parrallel to the surface you are needing to fit too. As long as the
pencil stayed perpendicular to the surface you are scribing on, you
should get a very close fit as long as you allow for any inside
corners.

BTW, I pretty much failed geometry, so feel free to correct my error on
this as I don't see where the problem is except for the price.

"vdubbs" wrote in message
ups.com...


I don't follow you on why it would not work. If the wheel follows the
surface and fits around the pencil, then the pencil would be held
parrallel to the surface you are needing to fit too. As long as the
pencil stayed perpendicular to the surface you are scribing on, you
should get a very close fit as long as you allow for any inside
corners.

BTW, I pretty much failed geometry, so feel free to correct my error on
this as I don't see where the problem is except for the price.

Take as an example a semi-circle. Run the wheel round the inside of the semi
circle and the copy will be parallel, but the new semicircle will be smaller
by radius of the wheel. Try it, like I did, with a pencil and a washer.

On Tue, 18 Oct 2005 17:35:24 GMT, "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.

This tool costs £23.95 in UK, I guess thats about $40 in the US. Trend make
excellent routers, trust me, I have one, I cannot believe that Trend, a
company I am sure you will know in US, could possibly have got this wrong,
so please guys tell me what I am missing.



actually, it works fine for profiles that don't vary a lot from
straight. fitting a cabinet scribe molding to a lumpy wall is a good
example of where it does work.

where it doesn't work is fitting around corners.

for the cost of a cup of bad coffee you can go to a hardware store and
get a handfull of assorted flat washers. they work just as well, and a
lot of hardware stores give the bad coffee away free.

Gary Dean wrote:


Take as an example a semi-circle. Run the wheel round the inside of the semi
circle and the copy will be parallel, but the new semicircle will be smaller
by radius of the wheel. Try it, like I did, with a pencil and a washer.

How do you make a "butt joint" with a circle?

--
Jack Novak
Buffalo, NY - USA

(Remove -SPAM- to send email)

vdubbs wrote:

I don't follow you on why it would not work.

Consider a profile of a half-circle.

With the disk setup, it will draw a segment of a circle of radius "x+r",
where x is the original radius, and r is the disk radius.

What you want is a circle of radius x, but shifted over.

Chris

vdubbs wrote:
Gary Dean wrote:
I have just been reading a tool catalogue and came across an advert forthis
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 thisdoes
not work.

This tool costs £23.95 in UK, I guess thats about $40 in the US. Trend make
excellent routers, trust me, I have one, I cannot believe that Trend,a
company I am sure you will know in US, could possibly have got this wrong,
so please guys tell me what I am missing.

I don't follow you on why it would not work. If the wheel follows the
surface and fits around the pencil, then the pencil would be held
parrallel to the surface you are needing to fit too. As long as the
pencil stayed perpendicular to the surface you are scribing on, you
should get a very close fit as long as you allow for any inside
corners.

BTW, I pretty much failed geometry, so feel free to correct my error on
this as I don't see where the problem is except for the price.

The device adds its radius to the radius of convex curves on
the original to produce the convex curves of the copy and it
subtracts its radius from the radius of the concave curves
of the original to produce the concave curves of the copy.

If you 'copy' the new profile(s) recursively on each new copy
the convex curves are broader while the concave curves are
narrower. The resulting profiles approach a straight line.
From then on the device will work fine. For profiles that are
smooth with long radiused curves the device will work 'good
enough' for some range of values of 'good enough'.

--

FF

Chris Friesen wrote:
vdubbs wrote:

I don't follow you on why it would not work.

Consider a profile of a half-circle.

With the disk setup, it will draw a segment of a circle of radius "x+r",
where x is the original radius, and r is the disk radius.

What you want is a circle of radius x, but shifted over.

Chris

Now this is the reason I almost failed Geo. I never looked at the
whole picture. I was thinking mainly about straight lines and corners,
not circles.

You could also just lay the pencil flat on the wall (or other flat
surface) and scribe that way. It is hard to hold perfect though and
will still give some error in a circle, but should give almost exact
transfer on a wall fitting for cabinet tops.

"Gary Dean" wrote in message

This tool costs £23.95 in UK, I guess thats about $40 in the US. Trend
make
excellent routers, trust me, I have one, I cannot believe that Trend, a
company I am sure you will know in US, could possibly have got this wrong,
so please guys tell me what I am missing.

This is simply a variation of an ages old cabinetmaker's trick, using a
washer and pencil, instead of a compass, to scribe to a wall.

--
www.e-woodshop.net
Last update: 10/16/05

In article ,
"Gary Dean" wrote:

It is basically a disk with a hole on the middle

AKA a washer.

The one drawback, as already mentioned, is the problem with inside corners.
The other problem is the lack of resolution as the 'disk/washer' will not follow
into a narrow groove, just averaging as it bridges across a narrow gap.
In most cases not an issue unless one makes it an issue as I just bloody well
did.

On Tue, 18 Oct 2005 17:35:24 GMT, "Gary Dean"
wrote:

...resulting in a perfect butt".

Since no one else has mentioned it, I thought Robin was the one with a
perfect butt.

--
LRod

Master Woodbutcher and seasoned termite

Shamelessly whoring my website since 1999

http://www.woodbutcher.net

Proud participant of rec.woodworking since February, 1997

On Tue, 18 Oct 2005 17:35:24 GMT, with neither quill nor qualm, "Gary
Dean" quickly quoth:

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 a -Profile- maker, not identical pattern-maker. Why are you
thinking it wouldn't work, other than missing any detail smaller
than its diameter?


This tool costs £23.95 in UK, I guess thats about $40 in the US. Trend make

$45 with Shrubby's new dollars. He's ruined our price break with
Canada now, too. Lee Valley is now like Nordstroms afa prices go.
grumble, grumble


excellent routers, trust me, I have one, I cannot believe that Trend, a
company I am sure you will know in US, could possibly have got this wrong,
so please guys tell me what I am missing.

Take a 1/4" flat washer and make one yourself for $0.04


- - - - - - - - - - - - - - - - -
If God approved of nudity, we all would have been born naked.
----- ----- ----- ----- ----- -----
http://www.diversify.com Your Wild & Woody Website Wonk

The device adds its radius to the radius of convex curves on
the original to produce the convex curves of the copy and it
subtracts its radius from the radius of the concave curves
of the original to produce the concave curves of the copy.

If you 'copy' the new profile(s) recursively on each new copy
the convex curves are broader while the concave curves are
narrower. The resulting profiles approach a straight line.
From then on the device will work fine. For profiles that are
smooth with long radiused curves the device will work 'good
enough' for some range of values of 'good enough'.


for most work of the trim carpentry trades where fitting stuff to
imperfect but pretty good walls, it's plenty good enough. the
introduced error from scribing a 1/2" deep bump 8" or 10" long (like a
bad drywall tape job) is less than the texture on the wall in almost
every case.


the flat washers are almost free, don't take up much space in the kit
and are easy and fast to use.

Not only will in not work when the imperfection is small enough that
the disk surface will bridge it, but who do they expect to spend $40
for a disk with a hole in it?


--

Larry Wasserman Baltimore, Maryland

Lawrence Wasserman wrote:
who do they expect to spend $40
for a disk with a hole in it?

people who don't know better? with that kind of profit margin, they
don't have to sell too many to pay for the catalog space. if trend is
having these specially made, they may have a problem selling enough to
cover costs, but if they're rebadging a brass fender washer it's pretty
much all profit.

the $40 price tag is really outrageous. I'd imagine that most people
who see it in the catalog who haven't ever seen it before and who might
actually have a need of it will have that little light bulb go off in
their head and toss a handfull of flat washers into their installer
kit.


OK, so I went and found it.

http://www.trendmachinery.co.uk/perfectbutt/

this tool is more than a flat washer, though a flat washer will do what
it does. the trend device holds the pencil for you too... for someone
who did a lot of scribing, like an installer of casework for a big
commercial shop, this could easily be worthwhile. for the rest of us, a
flat washer takes up a lot less room in the toolkit....

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

Tue, Oct 18, 2005, 5:35pm (EDT+4) From:
(Gary*Dean) doeth say:
snip resulting in a perfect butt". snip

Nina Hartley gets my vote.



JOAT
Sarchasm: The gulf between the author of sarcastic wit and the person
who doesn't get it.