Trimming the top and back overhang

The box is now put together and the next step is to make the top and back flush to the body.

Although it's a bit of work, I like to use hand tools for this. You can also use a router with a flush trim bit. I'll show what that would look like when I get to routing binding channels.



I mostly use a block plane and/or a small violin plane to flush the top and back.





I use a violin knife and/or a chisel to clean out the waist where a plane can't reach. Be very careful here, one slip could do a lot of damage. Sharp tools are a must. The sharper the tool the less pressure that you need to make the cut and less force gives more control.







I then use a scraper to level the sides. Also sandpaper on a block. The block is necessary to prevent sanding valleys or low spots.



You want the sides flat. This needs just a bit more work. I talked about "cupping" when I bent the sides to shape. If the sides cupped then the sides would be concave or convex instead of flat.



This is also a good time to check the arches and make sure that the top and back look good.

Here's the finger board back angle from the sound hole to the heel.



I also like to check that the lower and upper bouts are aligned on a plane. I should have mentioned this earlier, using a mold helps with this. If they are not aligned you can make some adjustment now but remember that the sides are pretty thin. So this needs to be checked before the top and/or back get glued onto the sides. That looks pretty good.

"Pretty good" is an understatement, that's beautiful work, mate. I'll bet you could build me a gorgeous set of stairs for my boat.

laklak wrote:"Pretty good" is an understatement, that's beautiful work, mate. I'll bet you could build me a gorgeous set of stairs for my boat.

Thanks.

hmmm. boat - Titebond 1 is not going to be good for that - it's not waterproof.

laklak wrote:"Pretty good" is an understatement, that's beautiful work, mate. I'll bet you could build me a gorgeous set of stairs for my boat.

I'm sure they would sound beautiful when you walk up and down them

Been following this thread John. Amazing and fascinating. And info overload. Thanks much.

Making binding and purfling

Binding is the material that goes around the edge of the guitar where the top meets the sides and the back meets the sides. On classical guitars it's traditional for the binding to be made of wood, On steel string guitars it's more traditional to use some plastic like material.

Binding protects the guitars from bumps and dings and it adds to the appearance by hiding end grains.

Purfling is the decotrative strips of wood between the binding and the edge of the top or back plate.

Here's an example of typical Martin binding and purfling.



And fancier Martin purfling with abalone shell.



Here's one I did with Koa binding and purfling and some rosewood and maple veneer.



Here's one where I added abalone shell.



You can buy all kinds of binding and purfling from places like here.

I'll be making mine.

The idea for the binding of this guitar is to let the figure in the wood be the decorative accent. Also, I used wood that I felt went well with the figure of the Myrtle sides and back.

I'm going to use a piece of ebony that has a bit of figure in it and I'm going to add a rosewood and maple purfling side stripe.

In general, I wouldn't recommend ebony because it can be hard to bend and can look like black plastic when all is said and done. Also, a simple binding without any purfling lines looks really good and that's what I would recommend for a first guitar.

I start by planning a flat surface on the binding stock.



It's best to use two hands.



I finish the job with a scraper. I have this old hoe that I like to use.



Then I band saw off a slice. I should be able to get 4 binding stirps from this piece.

Then I machine it to thickness with the safety planner. .25” is pretty standard, I'm going a bit thicker.



Clean up the job with the scraper.



Then I cut the maple veneer with many light passes of a knife. I make it a bit oversize to make gluing easier.

Usually I glue both veneer strips on at the same time but I don't have much rosewood veneer on hand so I'm going to glue that on by itself to make sure I get it aligned right.

I'm using Titebond but this is a great place for hot hide-glue too.

Squeeze out some glue.



Spread it out with your finger.



Clamp in place. Notice I have a piece of plastic (wax paper works well too) between the bench and veneer so that everything doesn't stick to the bench. A caul over the binding wouldn't be a bad idea.



Here I'm planing off the excess veneer.



And scraping it clean with a card scraper. Notice how it's flexed and angled down a bit.

You can also see the rosewood veneer that I've prepared next to the binding.



Add glue and clamp to the rosewood.

felltoearth wrote:

laklak wrote:"Pretty good" is an understatement, that's beautiful work, mate. I'll bet you could build me a gorgeous set of stairs for my boat.

I'm sure they would sound beautiful when you walk up and down them

Been following this thread John. Amazing and fascinating. And info overload. Thanks much.

I'm enjoying this section of the forum you proposed. That was a great idea!.

I marvel at the amount of toolery you use and wonder how the 'craftsmen of old' managed.

Alan B wrote:I marvel at the amount of toolery you use and wonder how the 'craftsmen of old' managed.

My teacher, Al Carruth, was fond of telling the class that the bandsaw replaced the apprentice of the past. But I suspect even Torres had access to some sort of power saw for the big jobs like book matching tops and sides. And I'm sure the Martin guitar factory that made the early steel string guitars in the 1930s was better equipped than I am with the exceptions of side bending which they did by hand. I patterned my side mold after one that C .F. Martin built in the 19th century.

Building tools to help build guitars is part of the tradition. The students in my luthier class would try to arrive a bit earlier than the others so they could grab one of the teachers hand made, or hand tuned, tools which always seemed to work better than our own. There was one little chisel I remember that was made from an old worn out file that was a particular favorite.

That said, the craftsmen of old, and some like my teacher, managed mostly with skill that they developed over time.

I should put together a basic list of tools required to build a guitar - it's not nearly as many as you'll see me use in this thread.

Slicing the binding to size

We left off with the binding/veneer stack glue drying.

Let the glue dry and remove the clamps. Since I have a fair amount of excess of rosewood on the log I'm going to trim it with a knife. Lots of light passes is the way to do this job.



And then a scraper to clean up a face of the log.



And the edge shows the binding and side purfling.







I'm going to use a small table saw with a jig that holds the log about .1” from the blade to slice the binding strips. (it's an old wet saw I used to tile my bathroom repurposed.) Use push sticks and keep fingers away from .... really be careful. This seems like a good time to remind people that you can buy binding.

Here's the log ready to meet the blade.



And a slice separated from the log. I shoot for about .1 inch at this point but my setup isn't that precise so I get .09” to about .11”. That's OK because in the end I'll scrape it on the guitar to its final thickness. You don't want to go any thicker than this because thicker will be too hard to bend.



After every cut I freshen up the face of the log so I'll have one good surface on every binding slice.



All four binding pieces cut. It's good to make a couple of extra pieces in case something goes wrong but the width of the board I was working with didn't lend itself to that.







And a little scrape to get the fuzzies off the cut side.

Yeah. By 'craftsmen of old' I meant a couple of centuries or more ago...

The list would be interesting. Not that I have any desire of 'starting-up' at my age. But I can dream...

Alan B wrote:Yeah. By 'craftsmen of old' I meant a couple of centuries or more ago...

All you really need is some good carbon steel to make blades and saws out of an a bit of patience. I remember one of my early teachers, Thom Knatt telling a story about how they book matched a Brazilian rosewood back with a hand saw - it took something like all afternoon to cut through it. I suppose it can be done.

The list would be interesting. Not that I have any desire of 'starting-up' at my age. But I can dream...

As I role the credits I'll show pictures of tools and flag the ones most necessary.

Making the purfling.

The next step is to make the top and back purfling. For this guitar the top and back binding and purfling will be the same but it doesn't have to be that way. I'm going to add a single thick (.06”) maple line and a single (.04”) rosewood line for top and back purfling. I wouldn't recommend such thick lines for a first guitar. You can use veneer or skip the purfling and just use plane binding. Of course it's easier to use plastic and that's a traditional look for steel string guitars.

I have some curly maple cut-offs from some sides of a previous guitar that I'll use.



By now you know the drill - I'll thickness them to .06” with the safety planer.



Scrape them to clean up the planer marks. You want to be careful here because the thickness is the part you'll see on the finish guitar and you don't want the line to be too uneven.



The top and back purfling is not as tall as the binding. It gets inlayed into the top at a depth similar to the rosette. About .06” (this has nothing to do with the line width of .06” that I just happen to have chosen).

I'll cut the purling a bit tall and plane it flush after it's installed. Something like .08-09” tall is good. Now we're talking about pretty small pieces of wood and I don't like getting my fingers too close to my small table saw so I use an even smaller one. I use a small saw blade on a dremel with a router base in a Jorgensen clamp. I tape a small piece of wood on the clamp to act as a bed for the saw and let the blade bite into it a bit.



And ready to go, actually I think I feed the wood from right to left.



Between cuts I plane a fresh face on the stock.



It's a good idea to make some extra pieces, I'll need four for the guitar top and back.





I have some rosewood already at the right thickness so I just need to rip it to height like I did with the maple. Here it is finished.



I taped the binding and purfling together to try to give a better idea of what the finished edge will look like.

Cutting the binding and purfling channels


The next step is fairly challenging. I need to make a channel where the top and back meet the sides so that I can install the binding and purfling.

But before cutting the channels for the purfling and binding it's a good idea to make sure you're happy with the
shape of the guitar.

Check for a hump at the tail. This could occur if the tail block was a bit too high.



Scrape and/or sand it out if need be.



Check for a hump at the heel. Use your hand and feel that there's no hump caused by the neck block.



And check that the sides are flat. I scrape and sand them as flat as I can get them, keeping in mind that the sides are already pretty thin. I use hand tools (scraper and sandpaper on a block) for this and it can take a bit of effort but it's a very safe way to do it. Now is the time to do this, it's too late after the channels are cut.



Now we're ready to cut the channels.

You can use a hand tool to cut the perimeters of the channel and then chisel it out. A gramil is used for the perimeter.





You use it like this.



This guy will teach you all about using that tool. Watching it, he almost convinced me to give it a go but I see him struggling a bit at the end ...



I was taught to use a router with a guide that controlled the width of cut. We just held the router by hand and went at it. It was a pretty unpleasant moment for most students. By the time we were ready for the router we spent about 1.5 to 2 years working on our guitar and the idea of holding a router over it was not good. But I only remember one student cracking a top and I'm sure Al fixed it for him - as best could be done.

Similar but a little more manageable is to use a dremmel tool with a router base with a guide. Something like:







You use it like so:



It works fairly well but the problem with dremels, laminate trimmers, and routers in general is that the doming that was put on the guitar makes it hard to get an even and level binding channel because the dome holds the router base at an angle. That is, the dome keeps the router from being at a right angle to the sides. So instead of getting a ledge cut perpendicular to the sides, there's a tendency to get ledges cut at angles to the sides - and that makes it hard/impossible for the binding and purfling to sit square in the channel. With skill, you can learn to hold the router at the right angle as you go but I have a helper that many luthiers employee for this job.

I'll be using a router. I have a bit that that tracks the side of the guitar with a bearing. The size of the bearing controls the width of the cut. It works fairly will but the bearing can scuff the sides a bit.



The bit set up for .08 inch binding thickness.



The bit in a router loaded into my router holder. The bottom of the holder has a doughnut which will ride on the top surface of the guitar. The doughnut only contacts a small area so it tracks the edge of the guitar.



Here's how the cutter, bearing, and doughnut meet the guitar.



The router holder is like an elevator, it rides up and down on drawer slides. This helps keep the bit perpendicular to the sides.





I use a full size router but a laminate trimmer would be better. I use a counterweight to help null out some of the routers weight. You don't want to eliminate all the weight though, you want gravity to keep it held to the guitar. My counter weight is some left over tiles from when I remodeled our bathroom floors.



My solera does double duty as a guitar holder. To route the back of the guitar I just clamp the guitar onto the solera.



And here's what it looks like all set up and ready to go.

Cutting the binding channel

Now that I explained the elevator router tool that I'll be using, it's time to actually cut the binding channel.

Here's the guitar being held securely by the solera and everything set up and ready to go.



Now the general rule for using a router is that you want to feed the wood to it in a direction against the rotation of the bit.
But the grain of the guitar plates is such that it's best not to go that route. The photo below shows where I start cutting and the direction I go from there.



Here's the first binding cut.



That looks good so I continue.



When I'm done with the back I flip the guitar over and level it out a bit with some shims.



The same routing directions are used on the top.







After you're done check the width of your route all over to make sure that there are no thin spots.



If you use plastic binding without purfling you'd be almost done.

Damn, I got all nervous looking at that router. I've had a few router disasters in my time.

laklak wrote:Damn, I got all nervous looking at that router. I've had a few router disasters in my time.

And we're not done yet!

It's fairly fool proof with the setup I have but it's still a nerve racking job. But nothing like it was back in the day when I was in class and we just held the router over the guitar and went at it. And it didn't matter whose guitar was getting routed, it was a scary operation for the whole class. And everything was magnified by the fact that we were working 1 day a week so it took about 1.5-2 years to get to this stage. It felt like 2 years of work could be trashed in a second. This hand held router techniques was not Al's best lesson, it was a bit cruel.

Maybe I need to practice more with a gramil -...

Cutting the purfling channel.

Now it's time to change the bearing so the cut will be wider. And adjust the route depth so the cut will be shallower. The channel cut by this new channel is where the purfling will go.



The purfling is only about .06-.07” deep. You don't want to cut through the top or the back, Remember, there's not much lining holding the top and back on.

A test cut is a good idea.



Check the fit.



Route in the same directions as for the binding. Here's a bit of the back done. Notice how much deeper the binding cut is than the purfling. This is what the final stair step cut looks like.



After the back is done, flip the guitar around, level it out a bit and finish the top.









A bit of sandpaper on something stiff will clean up the fuzz. Care must be taken not to round the edges. A file with a flat surface on one side might be a better tool choice.





And that worked out rather well.

So you cut right through the sides so the interior is visible? Why so deep?

Onyx8 wrote:So you cut right through the sides so the interior is visible? Why so deep?

The sides are pretty thin at this point, by the time I finish scraping and leveling them they're a bit under 2. mm in spots. Which is all pretty standard. Then route for the .08 inch binding which is right around 2 mm and you get what you see in the pictures. Blowing through to the interior is more likely when using tentellones then when using kerfed lining. The shallow kerfing I used for the back kept the router from the interior of the guitar- which helps keep binding glue from getting into places where you can see it from the sound hole.

.08 inch binding is a pretty standard dimension but you could go a bit thinner - .06 inch.

Seeing your question makes me wonder how the top manages to stay on the guitar after the routing but the tentellones are secured below the binding line and the X brace ends and transvers bar are secured in place and the neck and tail block help too. Your question made me recall being reassured by Al Carruth about 20 years ago that routing off the sides was fine and haven't thought much about it since. I checked Cumpianio's book this morning and you can see into the guitar after his binding route too.

Great question!

Bending the purfling

It's time to bend the purfling and binding to the shape of the guitar. Starting with the purfling

If I was using veneer strips I would just give them a quick bend on an iron but since my purfling is on the thick side I'm going to treat it like binding. I tape the pieces together so that I can bend all four pieces at once and they help support each other too.





You can use a bending iron for this but the thick ebony bindings can be tricky on an iron and the side bender makes fast work of this.



The maple purfling loaded and sprayed with water. The heat blanket is at 300F.



The waist is down and a caul helps bend the bouts.





Let cool and the maple purfling is done.



The rosewood purfling ready to go.



Bending the upper bout.









And some ranger rope holding the caul in place.



Do the same for the lower bout.



Let cool and it's done.



I saw this cool side bending machine the other day on youtube.