Sarah's Mandolin

[ScottR]

Next I sank the pointy ends of some paneling nails into the end and neck blocks, to create locators for the top.

I located the top and then pressed it down onto the points. Then I took it off and see if I could repeat placing it into the correct location.

Yes, yes I could.

SR

[ScottR]

Now it is time for a test set up prior to actually put glue on the wood and passing the point of no return. This is the first time I've used a set-up like this.

I cut up some 3/8" thick 70 durometer polyurethane--screen printing squeegee blade, and lined the edge of the spruce top with it, to protect the soft spruce top from the hard edges of the jatoba go-bars.

And flex the jatoba sticks and put them in . Woohoo! They did not break!

So I took it back apart, glued up the rim, located the top on the pointy ends of the paneling nails......successfully, replace the blue pads and started loading go-bars.

SR

[ScottR]

It looks like a sculpture to me.

And judging by the arch in the plywood top of the go-bar deck, pressure is being applied.

Back to shaping the backboard while the glue is drying. I worked the inside until the contours looked and felt smooth and then measured them.

I've got a few hundredths to clean up here and there but mostly it is spot on contour wise. I'll sand it smoother and dial it in. This should mostly be uniform sanding through the next few grits, since the contours are in the correct proportions.

SR

[psikoT]

Your next build is gonna be an acoustic, I can feel it...

[Andyjr1515]

I was interested in the use of a go-bar deck for gluing the top, Scott. That will be quite difficult to repeat to glue on the back...My preference is to use violin-style spool clamps for this kind of job.

i really am inspired by this build.  It is going to look wonderful when it is finished.  I just love the curves of the top and back. 

...and referring to @psikoT 's comment, it would be an interesting result for me to build a mandolin sometime and you an acoustic 

[Prostheta]

I love the idea of a go-bar deck and in spite of it being simple to break down and store, it seems a bulky thing to have hanging around. I'm surprised you didn't go the spool clamp route also Scott. Especially since you're a lathe-y kind of guy! I figured you'd have run off a bunch of spectacular clamps same as what I did. 

I've been playing a lot of acoustic lately too. So much so, that I might have to jump on that bandwagon sometime in the next two decades. I'd definitely go the archtop route first though, simply because cold laminated sides are an easier proposition for me over steam bent. I might even be able to press a laminated back....

How's this build feeling to you, Scott? It's very by the numbers, simply because it's a kit and a very established process. Is the zen of getting "everything lined up and as expected" working for you, or are you itching to get carving something that jumps out of your head? Or both? 

[ScottR]

7 hours ago, psikoT said:

Your next build is gonna be an acoustic, I can feel it...

It wants very bad to be one of these from scratch, just to prove I can......plus this feels like it is going to be a very cool little instrument.

But I have an electric design that's trying to form in my head that may have to come out first.

SR

[ScottR]

6 hours ago, Andyjr1515 said:

I was interested in the use of a go-bar deck for gluing the top, Scott. That will be quite difficult to repeat to glue on the back...My preference is to use violin-style spool clamps for this kind of job.

i really am inspired by this build.  It is going to look wonderful when it is finished.  I just love the curves of the top and back. 

...and referring to @psikoT 's comment, it would be an interesting result for me to build a mandolin sometime and you an acoustic 

Yeah, the go bar deck will be only useful for gluing the top. It will be spool clamps for gluing up the backboard. In the dvd companion to this kit, the builder has switched from violin clamps to spring clamps for gluing up the backboard to the rim, which is intriguing as well.

The thought of an acoustic build has been tickling a back corner of my mind for a few years now. Bending sides and joining really skinny wood is still an intimidating prospect to me. This project is intended to ease my way into that arena, and see where that takes me.

SR

[ScottR]

6 hours ago, Prostheta said:

I love the idea of a go-bar deck and in spite of it being simple to break down and store, it seems a bulky thing to have hanging around. I'm surprised you didn't go the spool clamp route also Scott. Especially since you're a lathe-y kind of guy! I figured you'd have run off a bunch of spectacular clamps same as what I did. 

I've been playing a lot of acoustic lately too. So much so, that I might have to jump on that bandwagon sometime in the next two decades. I'd definitely go the archtop route first though, simply because cold laminated sides are an easier proposition for me over steam bent. I might even be able to press a laminated back....

How's this build feeling to you, Scott? It's very by the numbers, simply because it's a kit and a very established process. Is the zen of getting "everything lined up and as expected" working for you, or are you itching to get carving something that jumps out of your head? Or both? 

SR

Like I told Andy spools are in line for the next stage. The rim seems a bit too skinny and light to be a candidate to squeeze between violin spools. Using the base of the go-bar deck to support it seemed the better option whilst gluing on the top.

I've had some crazy ideas about laminating sides too. I wonder how important it is that the sides be that thin in an acoustic. The top and back must be of course, but the sides?

Actually, I'm enjoying this build immensely. Except for bending and forming the rim, there is nothing in it that I couldn't confidently do--now that I know what is what and why that is so. On the other hand, there is very much skill work that needs to be done even though this is a kit. It is no where near to the point where "insert tab A into slot B and clamp to base C whilst holding flange D betwixt your left thumb and forefinger....." type instructions come into play. There is just enough done to get you pointed in the correct direction and some of the most specialized operations are done for you, but many are not. I am getting a great deal of pleasure out of shaping the arched top and back board. The body scroll need to be cut and carved. The scrolls in the headstock are cut but the top and back plates are not attached or cut to shape so those scrolls will need to be matched. And none of the binding channels are cut, so I'll have to do that including hand cutting the channels in all the scrolls. And my three ply binding is in separate plies currently so I'll have to learn how to make that lot come together.....neatly......with clean miters. All of which will be new to me. So I'm getting plenty of satisfaction out of this build.

I do have a rough design for an electric body trying to form in my head too, so the answer to your last question is both!

[Prostheta]

Well, that's entirely why I don't mind laminating the sides of an archtop. I true dyed-in-the-wool archtop would be bent sides and solid back/top. The vision in my head is still based around an ES-125/175 5-string bass. The back, sides, even the top can be laminated if needs be. I wouldn't mind a nice bookmatched carved flame Birch top though. It's just coming across the right piece.

The trick in doing clean mitres is to polish the back of your chisel to a mirror finish, and have it sharp enough to take the hairs off your forearm without any effort. My go-to chisel is 1" and gets used for EVERYTHING. It chops end grain like butter, and I totally baby the edge. I get stressed when it chops through anything and strikes the work surface. That kind of babying.

[ScottR]

55 minutes ago, Prostheta said:

I get stressed when it chops through anything and strikes the work surface.

I'm familiar with that kind of stress....

SR

[mattharris75]

3 hours ago, ScottR said:

I've had some crazy ideas about laminating sides too. I wonder how important it is that the sides be that thin in an acoustic. The top and back must be of course, but the sides?

 

Scott,

Here is a mandolin builder with some pretty cool processes that uses laminated sides, and actually uses them as integrated binding:

http://martinjacobson.com/id/?page_id=1131

His mandolins sound great. Although the integrated binding aspect might not work so well with an F style, I don't see why laminating would be an issue. Bluegrass players often have a pretty narrow idea of what a bluegrass mandolin can and should be, but people not as squarely centered in that genre don't tend to mind a little outside the box thinking. As long as it sounds good, then no worries.

[ScottR]

Thanks Matt. I agree. If it looks good and sounds good--mission accomplished.

SR

[Chris G]

I always had it in my mind to build a mandolin later years in my luthier hobby. ScottR you are always informative in your builds and can give a idea on the process. Looks Great!! 

[Prostheta]

Not sure if a mando would be in my near future. I've considered a pair of tenor guitars for my nieces though.

[ScottR]

Thanks. Chris.

This is my opportunity to dip my toes into acoustic waters, as it were. I'm learning a lot and having a blast with the archtop characteristics of this instrument. There are definitely more things to pay attention to than with electrics.

I did get the backboard arched and shaped properly during the glue up. I had an extra day, because of an extraordinary day of rain. I didn't flood, but all the roads between the house and the job did.

Next thing is to trim up the sides to see what the actual shape is and then create the scroll. The sides did not match the pattern exactly, and there were varying amounts of overhang, enough that I didn't know exactly what the outer shape of the scroll would be until trimming. Then I drew out my cut lines.

And carved to the lines.

And bandsawed to the cuts.....roughly.

SR

[ScottR]

Then it is a matter of making some specially shaped sanding sticks and cleaning up the cuts.

And then shaping and blending the volute with the rest of the top's shape. Volute is what they call the arched area in the center of the scroll's curl.

Next, it's time to fit the neck.

SR

[ScottR]

At first I was pretty disappointed with the way the dove-tail fit.

Then I realized that quite a few adjustments need to be made to get the thing centered and at the proper height and angle. That gap is required for wiggle room.

Careful shaving of the female side of the joint, mostly in the shoulders are required to perfect the fit.

I drew a centerline on the top and used the truss rod fillet piece as a pointer.....which told me the neck is pointing to the left.

For some reason I did not take straight on pics, but you can sort of tell that the above shot is off center and the below shot has been corrected by shaving a bit more of the left shoulder going into the dovetail.

SR

 

[ScottR]

I need the bridge in position to set the proper neck height. I need to fit the bridge to position it. It is supposed to be centered on a line drawn between the centermost points of the F-holes, which also is the center and highest point of the arch.

Shaping is done the same way it was done with the tone bars.

Which worked nicely.

I cleaned up the cut in the top to fit the 15th fret cross piece, and put it in place, pushed in the neck as it was fit so far, measured for the nut location, laid the fretboard in place and put a ruler that is just slightly higher than the frets on that. Then a level on top of that lot to see how the neck angle/height works with the bridge.

SR

 

[ScottR]

I set the bridge adjustment to just under half way up. And it appears the neck is too high.

So I took it apart and tweaked and trimmed till I got to this point.

Which looks like this from the back.

Time to tune the tone bars. I had shaped them to this point prior to gluing up the top.

SR

 

[ScottR]

Hmmmmm, lost track of my picture count. Pretend that last one is part of this post.

I made a tap tuning hammer out of an off cut of ebony--used to be a fretboard, and a shaped piece of screen printing squeegee blade.

I set a strobe type tuner......sort of anyway, it's still digital--on the tail block and tapped very lightly in the center of the bars. Using the tuner and comparing to plucked notes on my acoustic guitar, I shaped the bars until the bass side rang at A flat and the treble side at A sharp......as best as I could tell anyway. Removing material from the tone bars makes them more flexible, which yields a lower note. A stiffer bar yields a higher note......but there is no way to make a bar stiffer. so some degree of thinking is required.

Once I was satisfied, I glued on the kerfed lining to the bottom edge of the rim.

Ubiquitous clothes pin shot......

SR

[Chris G]

Fantastic Work ScottR!!

[djobson101]

Very interesting to see the attention to detail involved with this type of instrument. I especially like that volute and the fitting of the tone bars/bridge 

[psikoT]

Love the tuning hammer!

[ScottR]

Thanks Chris.

2 hours ago, djobson101 said:

Very interesting to see the attention to detail involved with this type of instrument. I especially like that volute and the fitting of the tone bars/bridge 

I walked into this project totally blind to what would be involved, and have received quite an education along the way. There is quite a bit of delicate wood shaping involved, and I am truly enjoying that aspect of the build. Likewise the fit of the neck joint irritates me somewhat, what with the extra voids. It is wedged in tightly enough and in the proper position....now anyway. It will be coming out again for a while. But I'm finding it a bit offensive that every square inch of joint is not perfectly mated. I cannot fix them all without changing the position, but I'm pretty sure the gap at the back of the dove tail will get plugged. It will make me feel better.

SR