Oaktown Strings

​Brace Top + Back

 

• Prepare the soundboard and back

  • Then draw a line about ¼ inch outside of the outline of the top and back.  Cut to outer line on bandsaw.

  • draw bracing pattern on soundboard and back.

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• Prepare the brace wood

  • Cut brace wood to the necessary height and width dimensions for the bracing pattern.

  • Apply radius curve to bracing using radius dish

    • 30’ radius for top of guitar.  Flat top for uke.

    • 15’ radius for back of guitar and uke

  • Cut lap joint in guitar x brace (ensure that joint is tight)

  • Use oscillating sander to taper brace ends where they meet the kerfing 

    • Also can just shape with chisel after gluing

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• Glue top braces 

  • Uke - Glue top braces on a flat surface in go-bar deck.

  • Guitar

    • Glueing is done in go-bar deck

    • Glue x braces first.  Use 30’ radius dish

    • Glue remaining below-the-soundhole braces in the radius dish 

    • Cut and glue bridge plate – in 30’ radius dish

    • Glue transverse brace, popsicle on flat surface 

      • Drill truss rod hole in transverse brace prior to gluing

      • Truss rod hole is 5/16 wide centered 5/16 from top edge of brace

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• Glue back braces 

  • Use 15’ radius dish for both uke and guitar back

    • If you don't have a radius dish, the ukulele back can be made flat.  A curved back ​is primarily for extra strength and durability.  A domed surface allows a thinner (and hence lighter) plate with the same mechanical strength.  

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• Trim braces to voice top and back

  • Height of braces at side wall should be 3/32 for guitar, 1/16 for uke

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Prepare Sides + Head/Tail Blocks

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• Bend Sides

  • Be sure sides are thicknesses and sanded to 180 grit

  • Cut sides to shape

    • Leave sides about 1/32 - 1/16 wider than final dimension

  • Bend sides on hot pipe

    • Bindings can be bent at this time.  Can be done two at a time.    

    • Bend kerfing

  • Cut sides to final length    

    • Use clamping cauls to be sure sides are tight in the mold

    • cut tail end of sides first to ensure good fit where tail piece will be located

    • Sand inside of sides (at least at head and tail blocks) with 180 grit to remove water marks from bending and provide good gluing surface

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• Glue head + tail blocks

  • Cut and shape head and tail blocks.   

  • Leave tail block square so it can be clamped easily

  • Apply shellac to sides and inside face of head and tail blocks 

  • Attach head and tail blocks to sides in mold using exopy with wood flour

    • Epoxy fills gaps that may be present due to imperfect fit over curved surfaces    

    • Wood flour stops epoxy from flowing out

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• Glue kerfing 

  • Check that side profile is approximately correct before gluing kerfing    

  • glue kerfing slightly above the side profile    

    • glue kerfing about 1/16 high at waist on back

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• Sand top and back

  • For uke - flatten front and sand 15’ curve into back kerfing using radius dish.

    • Clamps sides into mold with cauls when sanding    

  • For guitar back  - sand back in 15’ radius dish    

    • Clamps sides into mold with cauls when sanding    

    • Be sure head block angle is correct 

  • For guitar front - 30' radius below the sound hole.  Flat above the soundhole so fretboard will sit flat    

    • Use actual front as guide so front is not stressed when glued

  • Make sure sides make the proper angle with the soundboard.  90 degrees for uke.  About 88.5 degrees for guitar.

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Glue Up Body

 

• Cut back kerfing slots

  • If building a guitar, cut slot in head block for truss rod adjuster (if truss rod adjustable from body)

  • Bolt-on hardware holes can be drilled in head block at this time.  Or can be done later.

  • Route slots into kerfing to accept back braces

    • Mark the location of the slots. Mark and cut only two at a time for better overall fit.

      • Freehand route slots with Dremel using 1/8 inch bit

      •  Clean up edges of routed slots with safe file.

    • Depth of cut is 3/32 for guitar, 1/16 for uke

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• Glue back to body 

  • Gluing back first gives clean visible surface through sound hole

  • Sand sides to 180 grit to clean up marks from bending process

  • Glue back to body

  • Final clean-up and sanding of inside walls

  • Install reinforcing braces on inside of side-walls

  • Apply shellac to interior of body

  • Apply logo with fish glue

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• Route kerfing slots into side for soundboard braces

  • Use Dremel to route slots into kerfing to accept top braces 

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• Glue soundboard to body

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• Trim and sand

  • Trim soundboard and back flush with the sides using a downcut spiral bit with bearing  

  • Sand sides with 180 grit so that routed channels will be based on final side profile.   Sides may be carefully sanded with random orbital sander on lowest speed setting using a transfer pad.  Be careful not to over-sand or create issues.

  • Sand tops and back with 180 grit so that entire body is at near final shape

  • For a uke, make sure the sides are flat at the neck joint and square to the soundboard

    • For a guitar, the angle between the sides and soundboard at neck joint will be about 88.5 degrees.​

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Mortise Joint + Bindings

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• Route mortise for neck joint

  • Mark centerline on neck block.  The centerline should go down the center of the soundboard at the joint.

  • Mortise jig needs to sit flush against body just like the neck will.  For uke, sides at neck joint should be square to body for jig to align properly – i.e., a 90 degree neck angle.

  • Rout mortise in neck block using jig.  The jig has a 1 inch wide opening.  Using a 1/2 router bit and 3/4 OD brass template bushing gives 3/4 inch slot in body.   

    • jig is 1 inch wide ("W").  "d" is the outside width of the brass template router fitting (use the thin 3/4 fitting).  "f" is width of router bit.

    • width of cut in jig = (W - d) + f = 3/4 mortise slot for 1/2 bit and 3/4 template bushing

    • for guitar use shims to keep front of guitar against jig if the soundboard is curved above the sound hole. 

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• Cut channels + Install Bindings

  • Be sure joint at tailblock is filled and smooth where router bit bearing will ride.    

    • Same with respect to the joint at neck end of back.

  • Pad on shellac on soundboard to avoid tear out and dirt    

  • Route purfling channels before binding channels

    • For purfling, route along with grain of top/back, not the grain of the sides

    • Route with grain even if it means a "climb cut" with the router

    • Slowly rotating body against router allows controlled climb cut.

  • Route binding channels                

    • For bindings, route with the grain of the sides, even if it requires a "climb cut". 

    • If you don’t use a climb cut, tear out is highly likely        

  • Clean channels with sandpaper/file/x-acto knife

  • Sand still-attached fibers off of top.  Gently position fibers and sand them against their grain direction

  • Cut the channel for the tail block trim piece.  Use Japanese saw, dremel and chisel.

    • Much more difficult to cut this channel after bindings are installed.

  • Bend bindings/purflings – accurately bent bindings will make glue-up much easier

  • Test fit and cut bindings to size    

    • Front bindings can be easily cut to size because the fretboard covers the bindings at the neck end of the body

    • For the back, cut one binding to exact size and the other to approximate size (leave just a tiny bit long).  Then trim to exact size with x-acto knife during glue up.            

  • Use fish glue on bindings/purflings.              

  • Use scraper/small plane to level bindings with side    

    • Be very carful not to damage top while scraping/planing  

  • Use a large sanding block for final leveling of bindings