Acoustic Guitar Construction

These may seem obvious but I want to be absolutely sure
before I do this. After reading Ken's article I understand
how important rim sanding is to achieving proper neck angle....

Anyway,

1. When sanding the top edge flat. I assume that the rims should
be set a hair proud in the mold and then sanding will stop when
the top edge is even with the mold. Is that correct?.


2. When sanding the back edge to a 15' radius. Do I sand
the back edge flat first and then sand for the radius or
can I just sand for the radius immediately? Doesn't seem
like I'd even be able to sand it flat since the back edge
is contoured. I hope it's not too dumb a question; just
being careful.

Thanks!

Hey Mark,
Yes, set the rim a hair proud and sand the top edge flat. You then need to raise the neck portion, from the waist to the neck, proud of the mold, by the measurement Ken sets out in his instructions, and then sand only from the waist to the neck flush again with the mold.

For the back edge, you want to start sanding right away. Don't sand it flush first as this will remove the contour already built into the rim. You need to sand to perfect the linings to the edge of the mold and give them the radius that the back plate will have. Ken uses 15 feet as the radius. You also need to sand the eck and tail blocks to match that radius, and that's why you are sanding the back edge.

You should definitely review the procedure in the instructions before going forward, but it is not difficult. What you want, is to understand why you are doing things, not just how. If you know why, you are better able to accomplish the task. When you brace the back plate, the braces give it a 15' radius from side to side. Sanding the rim, along with the contour built into it, give the back a radius from neck to tail. This completes the dome of the back. Without the contoured sides and the sanding, you would only have a back plate arched from bass to treble bouts.
It is always best to ask before doing something so never hesitate to do so. I have heard of people gluing the neck on before checking the angle because they did not ask, and they wound up with a brand new guitar that was unplayable and in dire need of a neck reset! Asking before doing helps to avoid such tragic mistakes.

TonyinNYC wrote:Hey Mark,
Yes, set the rim a hair proud and sand the top edge flat. You then need to raise the neck portion, from the waist to the neck, proud of the mold, by the measurement Ken sets out in his instructions, and then sand only from the waist to the neck flush again with the mold.

For the back edge, you want to start sanding right away. Don't sand it flush first as this will remove the contour already built into the rim. You need to sand to perfect the linings to the edge of the mold and give them the radius that the back plate will have. Ken uses 15 feet as the radius. You also need to sand the eck and tail blocks to match that radius, and that's why you are sanding the back edge.

You should definitely review the procedure in the instructions before going forward, but it is not difficult. What you want, is to understand why you are doing things, not just how. If you know why, you are better able to accomplish the task. When you brace the back plate, the braces give it a 15' radius from side to side. Sanding the rim, along with the contour built into it, give the back a radius from neck to tail. This completes the dome of the back. Without the contoured sides and the sanding, you would only have a back plate arched from bass to treble bouts.
It is always best to ask before doing something so never hesitate to do so. I have heard of people gluing the neck on before checking the angle because they did not ask, and they wound up with a brand new guitar that was unplayable and in dire need of a neck reset! Asking before doing helps to avoid such tragic mistakes.

Thanks Tony!

Yeah, that's what I'm trying to do. Read carefully, go over Ken's articles and ask questions before I do
something. It's much better to go slow than make a mistake that will set me back. I love the process
and learning new stuff. This forum and the people on it have been great to me. I'm so glad that I
stumbled on Ken's site before I actually started building.

Anyway, thanks a lot and i will keep you guys updated...

You don't use the mold as a template for levelling -- just use a very large flat sanding stick as seen here:

http://www.kennethmichaelguitars.com/ri ... angle.html

Its assumed that you have the back edge of the rim already profiled -- is that correct? The kerfing should be proud of the side material do not level the back edge of the rim you'll screw it up and the profile will be gone -- not good. Use your contour sanding bar to create a uniform bevel along the entire perimeter, kerfing plus the side material.

kencierp wrote:You don't use the mold as a template for levelling -- just use a very large flat sanding stick as seen here:

http://www.kennethmichaelguitars.com/ri ... angle.html

Its assumed that you have the back edge of the rim already profiled -- is that correct? The kerfing should be proud of the side material do not level the back edge of the rim you'll screw it up and the profile will be gone -- not good. Use your contour sanding bar to create a uniform bevel along the entire perimeter, kerfing plus the side material.

Hi Ken,

Yes, I profiled the sides before I bent them. I just wanted confirmation on the sanding; albeit,
now seems like a dumb question. If I sand the back edge flat the contour will be gone!!!! Sometimes
I amaze myself.....

Anyway, for the top edge, I'm going to make the 24" sanding stick (per your instructions) tonight and will use that
as the gauge for leveling. Then I'll make the 13.5" sanding stick for the slope.

Thanks!

Update:

Over the weekend I made the 2 sanding sticks for the
top edge. One for sanding it flat and the other for the
slope. Everything worked very nicely. Now I'm on to
doing the 15' radius for the back.

i love this process:)

One more quick back rim sanding question:

Should I be keeping the back rim level when I
apply the 15' radius? I'm guessing it should be
level. I think Ken mentions this in one video....