Official Luthiers Forum!
http://w-ww.luthiersforum.com/forum/

routing binding
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10122&t=19741		 Page 1 of 1
Author:  Tai Fu [ Fri Nov 21, 2008 8:40 am ]
Post subject:  routing binding
Hi

I have a laminate trimmer that comes with the binding attachment that allows me to route binding with a straight bit. However the problem is on the back the angle prevents me from getting a good cut so without building a binding machine I was thinking why not cut the binding by placing the router base on the side rather than the back and cut from there?
Author:  Hesh [ Fri Nov 21, 2008 9:08 am ]
Post subject:  Re: routing binding
Tai Fu my friend great outside the box... thinking from you [:Y:]

I think that one of the possible reason why folks don't have the router base riding on the guitar side is that it would also need to register on the top and back. It's possible that anything registering on the soft guitar top, think Western Red Cedar, would crease it leaving a line.

You can make a donut which is a wedge of wood, I used MDF for mine, that is calculate to be the angle required to permit the router to sit up straight when sitting on the dome of the back and top. Of course both the top and back would be different angles unless you built them to the same dome. This donut attaches with double stick tape to the router base and then has a mark, visible, made at it's thinnest point. As you route around the guitar keeping the mark that you made always pointed toward the center of the guitar the donut negates the dome's ability to make the router tilt backwards. This makes for a more uniform cut all the way around the guitar.

Here are some pics of the donut that I made and used for a while. It worked very well.

Attachment:
DSC01525.jpg


Attachment:
DSC01527.jpg
Author:  Jeremy Douglas [ Fri Nov 21, 2008 9:54 am ]
Post subject:  Re: routing binding
I really like Bill Cory's Binding Router Guide. You still hold the router upright but the guide registers off the side rather than the top to cut at the proper angle and there is a small platform that rides just along the edge of the guitar to set the depth of cut. It makes perfect channels as long as your sides are flat. Btw, Bill Cory is the guy that runs the Kit Guitar Forum. http://www.kitguitarforum.com/

Here's a picture of it. Image

http://www.nichebooks.com/kgm/crg3-not-ebay.html
Author:  Michael Dale Payne [ Fri Nov 21, 2008 10:09 am ]
Post subject:  Re: routing binding
You must register off of both the top/back and sides. There are 2 planes to a channel, both vertical and horizontal. The top/back resister is required to control the depth of the cut form a given point and the side register is required to have a point to set the width of the cut. The combination of the two registry points set the pitch or angle of the cut.

The problem of using the side as the vertical plane is it puts the leading and trailing edges of the bit into a non planar relationship to teh intended line of the cut. This means the leading and trailing edge of the bit will be at times deeper or shallower than the intended but line. So the finished channel into the top will be at places over cut and at others under cut.

Because the top/ back is the non flat everchanging part of the body this is the surface that must index the depth of the cut. The side is flat and always in one axis. For that reason this is the plane best suited to control the width of the cut.
Author:  Michael Dale Payne [ Fri Nov 21, 2008 10:33 am ]
Post subject:  Re: routing binding
Michael Dale Payne wrote:
You must register off of both the top/back and sides. There are 2 planes to a channel, both vertical and horizontal. The top/back resister is required to control the depth of the cut form a given point and the side register is required to have a point to set the width of the cut. The combination of the two registry points set the pitch or angle of the cut.

The problem of using the side as the vertical plane is it puts the leading and trailing edges of the bit into a non planar relationship to teh intended line of the cut. This means the leading and trailing edge of the bit will be at times deeper or shallower than the intended but line. So the finished channel into the top will be at places over cut and at others under cut.

Because the top/ back is the non flat everchanging part of the body this is the surface that must index the depth of the cut. The side is flat and always in one axis. For that reason this is the plane best suited to control the width of the cut.


I am going to add to this by saying if it was possible to make a bit that had no width then it would be possible to use the side plane to index the depth of the cut. but since that is not possible, any width in the bit will lead to a given amount of error in the depth of the cut as the radius of the side changes. In other words the tighter the radius of the curve the more either the leading edge or trailing edge of the bit dips beyond the desired plane of the cut when the side is used as the depth index plane.

Doubt this? Draw out a profile of a body, desired cut profile and a router with a bit and watch what happens as you move the router around the profile while marinating the bit perpendicular to the cut plane. It gets even worse if you allow the bit to get out of perpendicular to the cut plane.
Author:  Rod True [ Fri Nov 21, 2008 4:37 pm ]
Post subject:  Re: routing binding
Another flaw in your thinking here Tai Fu (aside from what Michael wrote). What happens when you get to the waist? How will the router base ever sit flat in the concave surface of the waist? It won't

An easy thing to do (what I did on the first 3 guitars) was to make a tapered shoe and double stick tape it to the bottom of the trimer base. You have to be careful to not tip the router into the body, make sure you're always putting more pressure to tip the trimmer away from the body so the bit doesn't cut to deep into the top or back.
Page 1 of 1 All times are UTC - 5 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/