Other than the enjoyment of making musical instruments for yourself (and maybe others), the excitement from the first time of MAKING something probably called to most of us who build CBGs.

In the five years I’ve been making these, I’ve gotten invaluable advice from a few folks here that got fantastic results. I’ve been looking for chances to pay it back by paying forward, so I’m sharing this with anyone who might be thinking about trying it.

From day one I decided that that excitement was always going to be a part of this endeavor for me, so I set out my own ‘curriculum’ for learning and perfecting new techniques each year, if not with each build. After 5 years of building with neck-thru construction, I decided the neck join was the next place to develop building techniques. To be clear, this is NOT a criticism of neck-thru construction. Obviously, it’s a time-proven, tried and true, fool-proof method that holds many advantages. I just felt like I had to try other techniques for my own reasons.

Here are photos of the essential steps with some notes on my thoughts and lessons learned along the way. Hope they’re as useful for some as others’ have been for me.

The jig

I thought about doing both the mortise and tenon entirely with hand tools. For about 2 minutes. But I already spend enough time on building, so I decided to reach a compromise and cut the tenon by hand and do the mortise with a router. Hey, the ability to use tools – it’s what sets us apart..., right? (Well, that and typing snarky comments on YouTube.) I don’t have the space for a bulky ‘cabinet-style’ mortising jig that holds the guitar body while passing the router over, so I decided to flip things around and make a simple sled that holds the box securely while pushing it along the router table fence. The key here is getting EVERYTHING perfectly squared up. Considering I use a 2 degree neck back angle, that’s a biggie – you can’t afford anything to be off on any angle. I also designed it to be bottom heavy to ensure stability and safety – this will come up again later and can’t come up often enough, trust me.

Preparing the mortise block

I decided to go with an industry standard mortise dimension of 7/8” wide x 7/8” deep. Mahogany is the standard for its stability, strength, and lightweight, though Meranti (aka Philippine mahogany or the stuff they sell in the big box stores) will do fine, though it’s a bit softer. As you can see, I put a counter-sink for the bolt – not necessary, but I like a nice clean look.

Routing the mortise

Precision is everything with a mortise and tenon joint – you want accurate and maximum surface contact between the pieces. Clearing a lot of material out like this gets messy real quick, so it’s better to use two different size bits: a smaller bit to clear out the bulk of the material and then the actual size bit to make a cleaner final cut. You should also always use progressively deeper passes rather than trying to do the entire cut from the start. If you’re familiar with routing, you’re chuckling right now because you know this latter method is how toothpicks are made.

OK, SAFETY. THIS IS WHERE Y’ALL NEED TO PAY ATTENTION.

The router is probably the most dangerous power tool I own – there are so many things that can go wrong with it – and they all end very, very badly.
Stupid is really quick and easy. Safe takes time, but it’s worth it; I have two shorter fingers to prove it (but that’s another story, and tool). It’s critical that you DO EVERYTHING POSSIBLE to ensure MAXIMUM SAFETY and REDUCE RISK to an ABSOLUTE MINIMUM, as in ZERO RISK. To this end, I a few tips:

1. Score cut lines for your mortise on the box and remove some surface material to guide the router bit on contact with the surface. A router bit spinning at 3,000RPMs hitting a smooth flat surface WILL kick. Big time. That’s a bad thing.

2. Clamp the box securely to the sled.

3. Hold the box & sled assembly down firmly against the table and fence from BEHIND the pushing face/board - this bus ain’t gonna drive itself.

4. Make multiple passes of light and progressively deeper cuts.

5. Breathe a deep sigh of relief when you’re done. If you’re doing it right, you’ll have been holding it up to now. And go have a good stiff drink – of whatever is appropriate for you and those dear to you. You can admire your handiwork later.

ALSO NOTE the extra outside rail clamped down to ensure no movement of the box other than forward and the stop block to ensure proper length of cut on every pass. Again, precision is critical to a sound mortise joint.

Next time: Part 2 - The Horse Chestnut... (Dammit!)