SOBeach - 2014-12-11 5:19 PM
What?!  A store-bought jig???  tisk tisk tisk   (just kidding Dan) 

FWIW, I saw this really simple, clever (imho) home-made circle cutting jig...   https://www.youtube.com/watch?v=lj8kcjx201A

 

So when cutting these circles, I assume (yeah I know that's dangerous) you'd first route out the rosette inlay groove... then... using the same center pivot point, cut out the soundhole. ??

Yeah, I know. Pretty cheeky of me...

But, if I don't get acceptable resulst using the store-bought tool, I'm not above making something of my own.

Correct. The rosette groove is cut first, then the sound hole.

So, as promisted here's the latest news on the Balladeer project.

I had to set aside work on it because first, because we bought a house and needed to move from the old place to the new one. Then, I had to get the house straightened up and ready for the housewarming party. Lastly, I had to get the shop set up so that I could get back to the project. Phew!

Before moving I found that the saws I had were unsuitable for cutting the top wood down to make a 3-piece top and for cutting the strip stock to make the braces, more on the braces shortly.

I had purchased the AAA Sitka spruce sound board wood from StewMac, but it comes from them in 8-1/2" width which works for a 2-piece top. Since this guitar has a 3-piece top I had to buy two sets of wood to make three 6" wide pieces. My new DEWALT 15-Amp 10-in Table Saw worked perfect for cutting down the top wood and the braces.

Speaking of braces. If you recall I'd bought some Sitka spruce from the local aviation supply house. It's really nice wood and would be perfect for this project except for one thing. It's quarter-sawn, which is good. What's bad is that the grain runs sideways through the wood instead of up and down. After a lot of thought, research and a discussion with Jay, we decided it would be best not to experiment on this guitar.

Stradivarius used sideways grain on the braces for his violins. A few luthiers have done experiments to determine whether the strength is compromised when the grain runs sideways instead of up and down and the wood is equally strong both ways. If anything, it's a little stronger when the grain runs sideways, probably because the wood behaves like a laminated piece with hard layers stacked on softer layers. What has not been done is long-term tests to see if the sideways grain warps. Maybe someday I'll try building a guitar with the grain running sideways through the braces just to see how it sounds, how long it lasts, etc. But, for this guitar I used my new table saw to cut the braces from the blanks I bought from StewMac. (sorry for the yellowed images below. The CCD on my old camera was dying)

The braces in the pic below are those I cut from the StewMac blanks. The top wood has also been cut and jointed and they're ready to be glued together.

The top wood is really nice. It has a tight grain and good lacing. It should make for a good looking, great sounding guitar.

Rather than try to glue all three pieces together in one go, I decided to glue one joint at a time.

All three pieces are joined. The second joint didn't turn out as good as the first one. I reused the hide glue from the previous day and it had thickened up so it didn't flow as easy when I painted it along the edges of the wood. This made for a thick glue joint with gaps in a few spots. So, I steamed the glue joint apart, cleaned off the old hide glue and made a fresh batch of glue. The lesson I took away from this is to always make a fresh batch of glue.

Next is to take this to the woodworking shop and have them thickness sand the wood. After that is to trace and cut the outline for the top, start cutting the rosette groove and sound hole and mark the bridge location and drill the alignment holes.

Once that is done, I can start making the braces and marking their location on the underside of the top wood.

OMG...it is looking great Dan. That grain is killer. Totally on par or better than the RI's. Thank you!

very !!!  Dan.

I was finally able to take the top wood down to the woodworking shop to have it thickness sanded.

Next I notched the top edge for the neck.

And, fit it to the guitar.

I broke out my handy-dandy bowl bending plate.

I used it because it's flat, raised up off the workbench and it's got a slot for the fingerboard.

I traced the outline of the bowl. I didn't want to trust that the hole drilled for the strap button was on-center. It wasn't. It's about 1/4" off-center. Had I relied on the strap button hole, the seams of the top would have been crooked.

Bowl shape is traced onto the bottom of the top wood.

And, it's cut out and ready for routing the rosette groove and sound hole.

I put together the Dremel plunge router/circle cutter I bought and noticed immediately one big problem. It won't allow me to cut, either the inside of the rosette groove or the sound hole. Doh!

So, I ordered a proper Dremel circle cutting attachment that can be used to cut holes/grooves from 3/4" to 12" in size.

I decided to cut some grooves anyway on the practice wood I bought to get an idea of how it's done. I tried a standard cutting bit and it worked okay. I bought a real router bit and it works much better.

The scratches you see in the surface are marks left in the shellac. I'd read that some luthiers use shellac to 'harden' the surface to prevent tear-out of the wood. While there is some fraying of the wood fibers, even when the wood is shellacked, routing without the shellac actually works better because the plastic router base drags on the shellac but it slides smoothly on the bare wood. So, I'll probably leave the wood bare.

I'll post more once the circle cutting attachment comes in and I've had a change to cut the rosette groove and sound hole.

Well, it's taken this long for Home Depot to ship my circle cutting attachment. Next time I'll just order it from Amazon and have it here in a couple of days.

I used some of the leftover practice wood to get a feel for the circle cutter. When it comes to setting it up to get the exact size circle or the depth of cut, it's definitely not a precision instrument. Once it is set up for the right size and depth, it does a pretty good job of both routing and circle cutting.

Before I began, I peeled a little bit of the rosette from the old sound board so I could get an idea of how deeply they routed the groove. I discovered that the old rosette is constructed completely different from the RI rosettes.

The RI rosette is a single piece of thin (~.010") domed pearloid plastic, probably ABS. The grapevine is printed directly onto the front of the pearloid.

The original rosettes were a two-piece affair. The pearloid is the back layer and is about .015" to .020". The front layer is ~.020" clear domed plastic. The grapevine is printed onto the front clear plastic. Also, the rosette groove is fairly deep and It looks like the rosette was epoxied into the groove before the finish was applied. The groove is about 3/64" to 1/16" deep.

Needless to say, because of how thin the RI rosette is, the groove needs to be fairly shallow so the edges of the rosette are pretty close to the surface of the top wood.

Time to get practicing. This was the first groove that was the proper size and depth.

Test the fit of the rosette. Rosette fits pretty good.

The sound hole has been cut and the inside corners have been rounded with the router.

Voila! The wood is a little darker because I sprayed it with naptha to give some contrast to the wood and rosette. Also, the lower right corner of the sound hole has a bung. This is why I wanted to practice as much as I did. Each time I went through the process I found some other pitfall that would have wrecked the top wood.

About the time I pretty much ran out of practice wood I had a fairly good feel for the process. I decided it was time to do it for real. The top wood is clamped to the work board and the center hole is drilled.

Rosette groove is routed.

Sound hole is cut.

And, routed. There is a few burn marks. With a little sanding, these will come out.

Clean up the sound hole a little bit. Fitting the top wood to the guitar body.

Rosette is slipped into place.

Phew! That was a nerve-wracking job, but the rosette fits perfectly into the groove and the sound hole is rounded nicely.

Next job is the cut and fit the braces, then glue them to the back of the sound board.

"Phew! That was a nerve-wracking job"

Phew!!! That was nerve wracking to read! Dan, the top is looking freaking awesome. Thanks!

It is interesting that the 67 continues to give up secrets to how it all came together 48 years ago.