Doin' a Jig

No, not that kind of jig.
I mean a woodworking jig.

What's the difference between a template and a jig?  I think it's flexibility.  Having never done this before - I'm just guessing.  But it seems to makes sense...

A template is for making the same thing over and over in the same way every time.
A jig is for doing the same process over and over but with variable outcomes/outputs.

When is a wooden box and a couple of clamps considered flexible?
When it's a jig.

Take this angle/router sled jig.  It's just a box made with 1x3 stock that is big enough for the guitar to fit inside and a router to fit over.  The neat bit is if you add hinges to one side.  All of a sudden you can now use the router to make all kinds of cuts.  They are repeatable but also variable.
This jig is for adding a 4 degree pitch (or angle) to the guitar bodies.  The jig is supposed to be on hinges but I didn't have any on hand when I worked on this. If I add them I could make a 3 degree or 5 degree (or 22.5 degree!) pitch.

Once again - I'm adding the 4 degree pitch down near the neck pocket.  Les Paul necks (and PRS necks too) are angled away from the body so that the strings are parallel with the neck.  Take a look at this graphic.  It really explains the mechanics around why a Les Paul needs a neck angle but a Tele/Strat doesn't.

For this jig you have to make a temporary modification to your router.  Most routers have a removable plate (usually plastic) on the bottom.  The plate has four screws that you remove and the plate comes right off.

 Because it's removable it is also replaceable.  Usually you remove it and replace it with a new one when the old one gets worn out. But you can also use those screw holes to swap the plastic one for a wooden one (or attach it to a router table).  It's best to use a piece of plywood for this - as plywood is less likely to warp.  Keep in mind you want to be able to move the router laterally and horizontally, so it should be considerably wider than the box.

Do not attempt to adjust your monitor. There is nothing wrong with your computer.  

I used clamps to keep the jig in the right place.  It took a bit of looking but I was able to find a piece of wood in my scrap pile that when placed under one side of the jig made a 4 degree angle.  Not pictured is the angle gauge that I used to determine when the angle was correct.  There is a way to do this with trigonometry if you don't have a angle gauge.  Just google it.

The other thing that I did not take a picture of is how I secured the guitar body to the box.  There are a couple of ways to do this but I chose to use wooden shims to clamp the body to the box.  

Stick a couple of shims in the jig in-between the box wall and the guitar body  (see my crappy drawing below).  I put two at the neck and two at the tail.  Then tap the shims toward each other.  The pressure will clamp the body to the jig.

This is why I don't draw any more.

Just make sure the guitar is centered and squared up to the box or all of your cuts will be a little off.

Yes, I know.  There are two lines.  Look at the one in the middle.

I then drew a line where the router blade should start digging into the wood.

Then you lower your router blade until it just barely touches that line.  Anything between that line and the front of the guitar body should be removed at a 4 degree angle.

I found it easier to go side to side (left to right in the above picture) taking off small amounts on each pass.  The first couple of passes you remove a hair's width of wood but the cuts get deeper very quickly with the 4 degree slope.

If you do go back to front - you will find your cut becomes fairly deep fairly fast.  I think it was between 1/4 and 3/8 of an inch deep at the very end of the guitar body.  That's probably too much for one pass and you should reset your blade depth.  Also for this I used the largest/meatiest straight bit I had.  It also happened to be one of the sharpest bits I own - which is always helpful.

You may find that the sliding action of the wooden jig and the wooden router base plate may not be totally smooth.  It didn't bother me but if it bothers you you can try putting some bee's wax on the jig rails to make them glide a bit better.

It's kind of hard to see if you just look at the body - but if you look at the straight board behind the body blank - you can see how much was taken off.  The pen line on the side of the body matches up with the start line on top of the body in the above pictures.  

It's now time to shape the top!