Friday, April 20, 2012

Stewart MacDonald Herringbone Guitar Kit




This post concerns the construction of a kit guitar.  The particular kit is the Stewart MacDonald Herringbone Guitar.  This one is a dreadnaught style guitar with rosewood sides and back, spruce top, and mahogany neck.  This is the second Stewart MacDonald guitar kit that I have purchased.  Prior to this one, I built the Triple 0 Guitar kit by MacDonald with similar materials.  That guitar took one and one-half years to build.  Having assembled the tools and built the jigs required by the first kit and acquired experience with building a Stewart MacDonald kit, I am curious as to how long it will take to build a second Stewart MacDonald kit guitar. My initial goal is three months.  Other guitar building experience that I have included building a classical guitar at a luthier school from scratch.  That effort took three weeks.  I often say that was the hardest three weeks work in my life.  I am currently unconstrained by regular time obligations of a job.

Along the way, I plan to point out difficulties/uncertainties that I encountered in building the kit and perhaps help any fellow Stewart McDonald kit builders who happen upon this blog.

April 11, 2012

Pre-bent Rosewood Sides

Installing the Tail Block


The kit rose wood sides are bent and the quarter sawn book matched spruce top and rosewood bottom halves are glued together.

The kit instructions (CD and booklet)  indicate that the layers of cardboard are to be cut from the packing for the interior molds.  However, the interior mold forms are supplied pre-cut and there is no need to cut your own.  The precut forms are not to be used to align the neck block rather the cardboard packing is used for this.  I only used one full box top and used the sides of the box to form a double layer because I want to keep the full box bottom to hold the kit parts. 



 April 12, 2012


Installing the Neck Block

April 13, 20120

The following photos show slight misalignments in the ends of the neck and tail block with the sides as well as side with side wherein one is slightly higher than the other.  Not to worry, leveling of the kerfling with the sanding board, that you construcwill bring the neck and tail blocks and the abuttement of the sides into perfect alignment




The following photo shows installation of the kerfling.  This is not a very interesting shot of kerfling from this side admittedly.  However, note the tape on the inside of the brace that hold the sides of the guitar.  This is an innovation of mine.  The tape holds pieces of cardboard next to the plywood and provides a cushion to slide up and down the guitar sides.  Without this padding, the sides of the guitar are likely to get scratched when sliding the brace on and off the sides as they contact the plywood of the brace even though the arms have been rounded by filing.  I noticed this when building the Triple-0. For the Herringbone I also cut the opening a little to large and needed to compensate for that, so I used Gorilla(tm) tape over cardboard and discovered this provided a padding feature and liked it so I did not cut another brace. The interior height of the brace for the Triple-0 needs to be about one-half inch shorter than described in the booklet.  The interior brace dimensions in the booklet are the same for the Triple-0 and the Herringbone.  However the sides of the Herringbone are taller than those of the Triple-0. You'll discover this when the braced is attached and the guitar is laying top side down when attempting to glue on the back.  I used an additional board screwed across the open to shorten the brace arms rather than cut another brace. At this time, it appears I could have just cut the ends of the brace off by about a half-inch.  The width of the Herringbone and Triple-0 guitars at the waist are different so a separate brace is required for each kit.

April 14, 2012
Kerfling Leveled

This photo shows the leveled kerfling.  I did not include a picture of the sanding board used to level the kerfling along the sides and the neck and tail blocks.  Constructing the wedges with 5 and 1 1/2 degrees slopes for the ends of the sanding board requires some inguenity since measuring 1 1/2 degrees is rather small.  I used trig tangent function to determine the respective rise for 8 inch run. This step eliminates the minor errors in gluing up the sides and neck and tail blocks.  Installing kerfling calls for leaving the kerfling sticking above the sides by 1/32 inch, "proud" as woodworkers commonly say.  I discovered that my small six inch rulers is 1/32 inch thick and so used the edge of this ruler to set the rise of the kerfling above the side and end blocks.  Sanding the kerfling on the Herringbone was much easier for me than on the Triple-0.  Perhaps it was because the kerfling was more accurately placed or was it that I realized the instructions for drawing atop the sides with the white pencil meant atop the sides of the rosewood and not atop the kerfling itself.

Installing the top braces
 Notice the additional flat piece of plywood that serves as the top brace caul.  This needs to be a fresh piece of plywood to avoid maring the spruce top.  Gluing the braces to a flat surface seems counter intuitive to me since there is supposed to be a 1 1/2 degree arch in the top.  I'm not sure exactly what top brace piece is being installed in the above.  One thing that you will learn as you glue the braces in is that they have a tendency to slide once glue and clamping pressure is applied.  You need to consider this in planning your clamp placement sequence.  Clamping the ends of the braces first tend to make then more stable when clamps are added in the middle.  Reversing this order is almost guarenteed by make the braces start moving around. .  Also, it is possible to clamp small cauls next to the braces for alignment purposes and remove them once the glued brace is in place. The 45 degree cuts in the main braces for the sound bars and bridge plate to fit into need to be slightly generous since they will fill with a little bit of glue when they are glued down.

April 15, 2012

More pictures of top brace installation.  These are all dry clamped.  I find this part of the kit construction to be especially enjoyable.
















Ready for Top Installation

Note the razor saw in foreground, very useful for guitar construction.  Accurate triming of braces, etc.





Top braces glued in place.  Bridge clamping caul laying atop the braces.  This will be used to install bridge on the top side of the top much later.  Notice the maple corners which are glued at the corners of the the bridge clamping caul.  These are made from the bridge plate material according to the directions which I have a hard time understanding.  The picture in the booklet does not clearly indicate that there are three levels to this caul, but there are.  I cut the channels, installed the corners, and recut the channels in the maple corners to avoid trying to cut and install the small triangular pieces.  The Herringbone bridge clamping caul is significantly different than that of the Triple-0.  The Triple-0 bridge plate is longer in the waist dimension than that of the Herringbone.  There is only one channel in the Triple-0 bridge clamping caul that I constructed.  The picture in the booklets are the same for the Herringbone and Triple-0 however.

The following picture shows the bridge clamping caul in position.

The shoulder brace caul to be used later in attaching the fingerboard is the same for the Herringbone and Triple-0. 

Aligning the top to mark the channels to be cut for the brace ends.  At this point I noticed that the body of the Triple-0 is specified as 3/8 inch longer than that of the Herringbone which I found curious.  The body of the Herringbone is deeper and wider and thus has more volume but the body is shorter.  The Triple-0 has 12 frets to the neck whereas the Herringbone has 14. I believed the Triple-0 to be a smaller guitar, but the body is longer, odd.

I reverted to mounting the guitar on the top brace caul to position and align the top on the sides to mark the locations for the top brace channels in the sides.  I made a slight mistake in that I cut the top brace ends flat to 100/1000 ths (0.1 inch) rather than following the arc of the braces.  I made this same mistake on the Triple-0.  While this may not be noticeable in the finished product, it could be argued that flat brace ends contribute to a more flexible top or a less strong top.  The effect is probably inconsequential .  I also discovered that one of my small files is 3/32 (0.09375) inches thick.  I used this to gauge thinning of the brace ends.

April 18, 2012


Channels for brace ends cut in rosewood sides.



Neck channel for bolt on neck cut open.  The Triple-0 has the dove tail neck which I had a hard time fitting.  I opted for bolt on neck for the Herringbone hoping that the installation will be easier.



I experienced the top sliding around once glue and clamp pressure is applied while building the Triple-0.  I decided to try installing two small 1/8th inch dowels in the top and neck block to anchor these pieces together while I glued the top onto the sides.  This worked real well.  These pins will be hidden by the fingerboard once it is installed. 


Another picture of the two small pins.  Notice the channels in the kerfling and the spool clamps strategically placed for gluing on the top.  I dry ran clamping the top at least two times as recommended by the directions.


The top is glued on looking just like Stewart MacDonalds pictures.  The work stand is my router table which is proving convienent for building the guitar kit as you can access all sides easily and it is a comfortable height, at least for me, of 44 inches.

April 19, 2012

While the top is drying, I began work on the back.  The kit includes the halves cut and glued.  This piece includes a lot of curvature and should be rather striking once it is finished.  This is the good side, it will be on the outside of the guitar.


Another view of the router table with top glued on.

April 20, 2012

Installation of Back Braces



Beginning of glueing back braces to back.  The back caul provides for the curvature of the back.  This curvature is the same for the Herringbone as the Triple-0 so I did not have to make a new caul. The small metal clamp anchors alignment blocks to keep the back brace from moving around once glue and clamping pressure are applied.  While not visible, there is a similar alignment block clamped on the other side.  I don't recall how I solved this for the Triple-0 but there is a definite issue with keeping the braces in the desired position when glueing. 


Alignment blocks and clamps removed.


I trimmed the top overhang with a utility knife, razor saw, and file while waiting for the back braces to dry.  I only have one back brace caul so need to do four clamping sessions for the back braces plus five clamping sessions for the back strips.


May 19, 2012


 The body is finished.

June 2, 2012


My previous attempts at detailing the difficulties I encountered in routing the channels for the purfling came to naught as I hung the text entry by attempting to insert a picture.  Perhaps I edited for too long a time.  Anyway the jig that I bought for this purpose did not work on this dreadnaught guitar. The angle of the back was too great to allow the router to ride up along the back.  Plus there is an issue with the body being warped.  I'm not sure how this happened but the resting the body on its side so that the upper bout and lower bouts touch reveals a distinct difference depending on the whether the left or right side is down. In addition the top does not have a symmetric arch.  Lying a straight edge diagonally from the upper to the lower bout reveals that the top is arched on one side but not on the other.  This also complicated attempts at using the jig.  I therefore resorted to free-hand cutting the channels using the Bosch Colt edge trimmer router and the Stew-Mac cutter and router bear set with careful measurements facillatated by the digital micrometer.  I used a "five-degree" wedge for the base of the router on the back as prescribed in the manual and DVD.  I determined the "five-degree" angle by eye-balling.   It turned out just fine.  A little apprehension at approaching the guitar with a whirling router knowing that a misguided router cut could ruin the guitar top or back beyond repair. Scraping and sanding to remove the dried glue and smooth the binding to match the edge of the guide was the final step in prepping the top for finishing.  I also use a straight edge razor blade in this process, it makes a dandy mini-scraping - a tip I picked up somewhere.  Applying finish to the top must wait until the neck is finished and fit to the body, else scraching of the body would surely occur. 



 
May 19, 2012

 The finished body, awaiting neck fitting prior to finishing.

May 21, 2012 

Building the neck first proceeds by trimming the pre-slotted fingerboard to fit the neck.



May 23, 2012

Installing the side dots is next.

May 24, 2012

Installing the the fretboard inlays is the next step.  The kit provides mother of pearl dots.  My experience with building the Triple O included installing Abalone diamonds and squares which are much more striking in appearance.  Thus I elected to install Abalone diamonds and squares in the fretboard of the Herringbone guitar.  I used an X-acto knife and a 1/8th inch chisel to dig the openings for the inlays.  A more exacting appoarch would be to use a router and 1/32th router bit.  Installing the inlays with blackened epoxy makes it possible to hide inexactness of the cuts.  Starting with a paper pattern overlaid with a tracing of the individual diamond and square taped to the fretboard provides an accurate starting for cutting the hold for the inlay.  The Triple O directions indicated starting with a drilled hole and then squareing the edges which worked okay.  Using a pattern is more exact for smaller inlays.


 Close up of diamond inlay in its hole prior to glueing.

May 26, 2012
 The inlay holes without the inlay

June 2, 2012 
Finished inlays.  They were glued in with structual slow set Epoxy colored with black color.  Using Ebony dust for coloring is another possibility. The inlays were then scraped and sanded smooth with the fretboard surface.  A black oil dye was applied to the fretboard in an attempt to hide the natural light brown discorations in the Ebony.  I've had mixed results with attempting to darken Ebony.  This application worked better than on the fretboard I built for the Triple O.  Sanding to 220 grit is recommended per the directions, sanding to 320/400 makes the fretboard feel smother at this point.  Whether finer sanding results in smoother feeling action remains to be seen.



This customization step slowed down the time schedule for the overall guitar. I need to complete the neck by the end of June to meet my goal of building the guitar in three months.

 June 4, 2012 

Working on the peghead requires having the tuners available, I needed to order a set.  I selected the Waverly nickel vintage tuners with ebony buttons from Stew Mac.  Once I had the tuners, I proceeded to ream the holes for the bushings using my available reamer.  Eventually I realized that the reamer was not going to cut the hole large enough at which point I noticed that the reamer I was using was the bridge/end pin reamer, not the peghole reamer as pictured in the directions and DVD.  Yuk, that means I cut a incorrect hole that needs patched.  I subsequently considering ordering the Stew-Mac Peg hole reamer at $113.65 but instead decided to try the peg hole bushing reamer at $17.25. Cost is a consideration at some point. The exact size might be an issue since the Stew-Mac page for these items writes that the 0.340 inch size is intended for Waverly Tuners while the specifications for each tuner indicate 0.348 inches widest diameter. How to reconcile these two different measurements?

June 16, 2012

Once again I lost text updates while uploading images.  If blogger wasn't free, I'd attempt to do something about it besides select update more often.  Geez...

So there I was reparing the peghole that I reamed out with the wrong reamer and then drilling out the tuner holes with a 1/4th inch bit using a the drill press. Prior to gluing the fretboard onto the neck, I gave it a coat of the black oil dye from Stew Mac in an attempt to hide the brown in the ebony.  This doesn't work very well, the brown is still visible. I also coated the peghead rosewood veneer pan since this particular piece of  rosewood was very uneven varying from purple to tan.  Sanding removed a lot of the black but not all.  I considered binding the peghead to hide some chips in the edges but can't quite decided how to do it so I'll pass on that diversion.



The incorrectly reamed out tuner hole which is still too small for the tuner bushing.


Except for this side, the reamed out hole is way too big for the tuner shaft.


Patching the incorrect tuner hole with a hardwood dowel sanded to a taper.  Building a guitar is a matter of hiding one's mistakes.


Tuner hole patch from the other side.


Fret board after black oil dye treatment.  Notice how nicely the diamonds and squares inlays sparkle.


Preparing to glue the fretboard onto the neck using the  Stew Mac technique of inducing a slight downward bow by securing the peghead in padded vice jaws and raising the tail end with a stick which compensates the upward bow in the fretboard induced by installing frets.
Gluing the fretboard to the neck as prescribed by Stew Mac.  This approach works really well, the resultant neck appears to be perfectly flat.



The fretboard is now glued onto the neck and the diamonds and squares are still sparkling.


The peghead holes are drilled for the bushings and enlarged for the tuner shafts.  I can't imagine that the $113 peghead reamer would work better than the $17.50 drill reamer or whatever they're called.


The next step is fitting the neck to the body.  As shown in the DVD and manual, this appears to be a relatively easy step.  However, I spent considerable effort in obtaining the desired alignment of the neck with the bridge.  The step of cutting the channels along side the tenon is complicated by the fact that one is chiseling end grain.  This is not as easy as it seems because the wood is tough and removing wood appears to be reveal wet wood underneath. Which, of course is ridiculous.  Letting the cut sit over night does seem to make it easier to cut briefly.  The tenon does not appear to be perfectly centered in the heel of the neck.  I resorted to slightly shaving the end of the tenon in both dimensions as well as scraping the mortise channel in the body to obtain my final fit.  It appears that the height of the tenson matches the depth of the mortise exactly so it was necessary to alter the joint slightly, contrary to the Stew Mac directions. I found this true on the dove tail neck joint of the Triple O also which required even more alteration. 

I wonder if this is a manisfestation of the top lacking the prescribed bow due to method that the top braces are installed.  If I build another Stew Mac kit, I'll use a go-bar deck to install the top braces.

 It's also helpful to press down on the neck into the body mortise channel when dry fitting to get the neck extension to fit closely to the body top..

 The final fit is not "perfect" where the body meets the tail of the neck as the line of a crack is visible.  I eventually obtained 4/32nds equal spacing on both outside bridge holes with a straight edge held against the neck side and exact alignment with the straight edge on the neck top to the top of the bridge.


The nut and bolt of the bolt on neck visible throught the soundhole.


Dry fit neck.

 Heel to body fit, looks better in picture than it really is.



Fit of heel to body on the other side, notice chip at the top.  I considered installing a piece on binding on this joint but the inner heel has been cut to a narrow ridge and there may not be enough material to cut a channel for the binding.


Fretboard inlays still looking nice!


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