Monday, November 24, 2014

LeSpork Bass Prototype - The Load Out

But when that last guitar's been packed away
You know that I still want to play
So just make sure you got it all set to go
Before you come for my piano

Just when my son got used to having a bass in his room to play, I found some time to get back to this project. The list of things to-do includes:
  • final-solder the controls
  • replace missing control cavity and truss rod covers
  • make and install a custom pickguard
  • install a thumb rest
  • refinish the body and headstock 
  • realign the neck/body/bridge 
  • install neck bolt inserts
I took the bass back out to the shed and took a few critical measurements, and put some thought into the best order to handle the to-do list.  The electronics would need to be worked on outside of the cavity, so I desoldered the output jack, pickup leads and bridge ground wire, and pulled out the controls and jack.

I was still undecided on the overall color scheme, including the color and material choice for the missing control cavity cover.  Since I had narrowed my material choices down to wood and plastic, I went ahead and made a control cavity cover from some scrap wood.  The wood cover would certainly come in handy as a template if I were to go with a laminated plastic cover to match the pickguard and truss rod cover.

Before completely tearing down the rest of the bass, I thought it would be best to realign the neck/body/bridge and install a set of neck bolt inserts.  This would ensure that I could properly set the bass action and intonation, as well as to be sure to plug all of the extra holes in the body and neck before doing the refinishing work.  I took a few critical measurements and determined that an adjustment of the bridge towards the lower upper bout by 3/16-inch would realign the strings with both the neck and the pickups as well as to allow me to use the neck-to-body angle as it was.  The neck set angle could still be adjusted by shaping and shimming the neck pocket during setup.

In anticipation of the finish work, I mocked out a headstock modification to make it look more like a Kramer and laid out a Spork shape for the pickguard on the body with some painters tape and markers.  The pickguard would be too close to the pickguard, so I added 'relocate volume control' to the to-do list...

To be sure I would only reset the bridge location once, I thought it would make sense to first lock in the neck-to-body angle by installing the brass neck bolt inserts and stainless steel neck bolts.  So, I drilled out the existing neck bolt holes to the required 1/4-inch diameter and installed the inserts.

Working without a drill press or hole guide, the body/neck bolt holes I made in this bass were out of plumb.  A smart way to increase the size of these holes would have been to use progressively larger drill bits, allowing the drill bit to be guided by the existing hole.  In a rush to get this step done, I overbored the 1/8-inch holes with a 1/4-inch drill bit.  After installing the inserts, I found they did not line up with the holes in the body.  To fix this meant rework in plugging the body and neck holes and redrilling the holes.

The upside to this setback was the opportunity to make an adjustment to the neck/body angle.  After a day for the glue to dry, and some work with files, a chisel and some sandpaper, the neck and body were ready for a shim, a new set of bolt holes and proper installation of a new set of inserts.

Tuesday, July 8, 2014

Flat Top Tele - Dust In The Wind

I close my eyes only for a moment, and the moment's gone
All my dreams pass before my eyes, a curiosity

In addition to this being a prototype build, I have been developing forms and learning new ways of doing things.  With so much of this project expanding my skills, there is an underlying angst with this project. One bad slip-up, and all of my work would be worth no more than sawdust in the wind. I've already had some bad results that have led to doing things other ways, and I've had some good results that have confirmed my intuition.  So, I have decided to make use of some of my practice work on the Flat Top Tele that went well, by using it to build an thin-body electric semi-solid version of the Flat Top Tele.

Yes, this project scope just got doubled in many ways, and hopefully is getting at least twice as better for it.  This will give me a chance to work through some of the body assembly issues on cheaper laminate woods before performing them on more expensive solid tone woods.  This guitar will be part Les Paul's "The Log" and part Fender Broadcaster, and built with Fender-type hardware, bolt-on neck and pre-wired electronics.

The success I had with bending the laminate sides inspired me to try making the sharp curves at the cutaway, using my steam box and a four-part bending jig.  I'll also try using my bending iron and some joinery to produce the distinct upper bout curves at the neck-to-body joint.  These also seem a lot more doable with a narrow 2-inch thin-body design.  Here is a sketch and partial parts layout of the jig for forming the sharp cutaway curves from steamed side wood.

If all goes as planned, I'll use a small interior block to splice the cutaway potion to a section that makes up the rest of the waist and the treble-side lower bout.  That's enough for now, on this warm summer evening, with This Old Guitar.

Monday, July 7, 2014

Flat Top Tele - Shipbuilding

It's just a rumor that was spread around town
A telegram or a picture postcard
Within weeks they'll be re-opening the shipyards

Some would say that bending sides of an acoustic guitar are a lot like shipbuilding, but with fewer parts, people and melodrama.  Like the underlying structure of a wooden ship, the guitar sides plus end blocks and linings are referred to as ribs.

Like building a concrete wall, it is necessary to build forms that are the negative, or outside, of the shape of the guitar sides.

Because of the complexity of the angles and curves of a guitar, as well as the tendency for bent wood to return to its unbent shape, it is common practice to use forms that sit inside of the guitar body when forming the sides, and another set of forms that sit on the outside of the guitar body when attaching the linings and the front and back panels to the sides.  Below are sketches I made while designing the form work for the Flat Top Tele.

Most modern manufacturing processes make use of CAD/CAM to produce highly accurate machines parts to close tolerances from scaled computer drawings.  With so much free information on the internet, finding a free, printable scaled drawing was quick and easy.  CAD/CAM technology is beyond the modest means at These Old Guitars at this time, so I used a tried-and-true manual method to make a tracing of the Telecaster body shape.  Starting with a full-sized plot, I applied a layer of graphite (aka pencil lead) to the rear side of the plot.  After taping the plot down, I used a stylus to transfer the outline onto a 3/4-inch MDF board.  To make it easier to see the outline on the MDF board during cutting, I drew over the pencil line free-hand with a marker.

The inner and outer forms I cut from the first MDF board served double duty as both forms and templates for the other forms.  I attached pairs of forms to each other and clamped the pairs together before shaping and sanding, so the forms would end up smooth and with matching curvatures.

I added some 2x3 blocking between the MDF side boards of the interior forms and a layer of 1x6 between the MDF side boards of the exterior form to get the proper finished form widths.  I used some wood filler on the outer forms to get a smooth, continuous surface.  Some additional parts including some PVC piping were sized and made ready, to be used to hold the bent wood against the forms.

With the inner and outer forms fully assembled, I warmed up my steam box and prepared my work areas for some wood bending.

Thursday, June 19, 2014

Flat Top Tele - Thick as a Brick

So you ride yourselves over the fields
and you make all your animal deals
and your wise men don't know how it feels
to be thick as a brick.

As an art student at SUNY Binghamton during the early 1980s, I had the privilege of studying sculpture with Prof. Ed Wilson.  Wilson was well versed in many materials, including wood.  One lesson in particular I learned in that class may as well have been taught in an engineering or architectural design curriculum.  Part of the creative process of art is figuring out how to execute the piece.  So, a working knowledge of the medium is something an artist needs in order to be able to execute a vision.  In this way, this neck block is as much about how to construct and attach the layers of wood, and then attach the rest of the body and the neck to the neck block, as it is about how the assembled functions when the body is attached to the neck.  Time will if it was wise to make such a large neck block for this build.  With the top and bottom panels, this Flat Top Tele build certainly will be as thick as a brick.

Adding some temporary struts to the template made a big difference.  Cutting closer to the template outline with a jigsaw before using the router on each layer also made a big difference.  I also made sure to pay extra attention while making the cross grain cuts, being sure to hold the wood firmly against the saw table while cutting with the router.  Another change I made was to use the neck plate  pattern for the wood screws when attaching the template to each layer.  This proved to also be helpful in aligning the layers during glue-up.  The thick part of the cutaway proved to be the weakest point in this process, and I suspect this was a combination of cross grain cutting direction and the small radii.  Although I broke two of the layers during fabrication, the breaks were clean enough that I was able to repair and use them. As a result, the 1/2-inch thick top layer and one of the 3/4-inch layers have a few extra small screw holes from how I attached them to boards while making the repairs.

Before gluing the five layers to each other, I roughed out the neck pocket cutout in the top layer, and bored out the holes in the other layers for the neck bolts.  Since the body is so thick, I'm using 3-1/2-inches long, #10-32 machine bolts.  A set of #10-32 threaded brass inserts in the neck heel will receive the bolts.

When I first thought about how to glue-up the neck block,I figured I'd glue them all at the same time.  When it came time, I realized it would be easier to control the alignment of the layers and removal of squeeze-out glue by attaching just two layers at a time.  To help keep the layers aligned, I made a clamping jig from some scrap wood.  Since I had already made the rough neck pocket cutout from the top layer, it did not have neck bolt holes to help with the alignment.  So, I clamped directly against the outer surfaces of the layers to align them against the jig, and added bar quick-clamps to hold the layers flat against each other and the jig.

After the glue had dried and clearing off some excess glue, I moved on to adding the third layer.  Since I could now use the neck bolts for alignment, I trimmed the size of the jig, making it possible to use more clamps to hold the layers flat against each other and the jig.  Here's a picture of one of the layers with glue on it just before clamping.

The rest of the layers glued up without any surprises.

All ready for some work with some files and sand paper, I stopped work on the neck block assembly a few days ago, taking a break from an early summer 2014 heatwave that was gripping the east coast. This was the perfect time to get caught up on some things in air-conditioned comfort, such as accounting at These Old Guitars, and creating a company website with my long-time guitar-playing friend and website designer.  It was also a good time to put a little more thought into some of the processes I would use for the bent wood portions of this old hollow Tele body, as well as final design of her internal bracing and some forms for assembling her body.  There was also some more electrical control design work to be done with the help of long-time guitar-playing friend and electrical engineer on that LeSpork Bass project...