STEP BY STEP - 4

GLUE BACK TO RIBS.

  1.                     Rough trim linings to profile of back.  

I preshape my ribs to the back profile before I bend them so this is mostly done.  I use a small block plane to trim the linings to match the ribs and to put some of the side to side arch into them.  The real shaping is done in the next stage.

2.                    Sand profile into back side of ribs with domed sanding jig.  

One of the most useful inventions in the guitar building trade in recent years is the invention of domed sanding forms.  Essentially they are pieces of plywood or MDF about 24" in diameter which have had one side cut to a concave shape.  For backs this is generally a curve of about a 15 foot radius.   Many makers use a similar form with a 25 foot radius for the top.  The concave side of the form is covered with self adhesive sandpaper (I use 60 grit) and rotated around the ribs.  I do this by cutting a hole in the middle of the form and rotating it on a piece of pipe sticking up from my workbench.  (Photos here). I mark the rib/linings with pencil and sand till all the pencil marks are gone.   This is quite easy and results in a very nicely shaped rib/lining combination.  Since my back braces are curved with  a 15 foot radius, the result is a perfect fit between ribs and back. 

3.                    Carefully locate back on centerline of Ribs.  

This is important for visual effect more than anything (minor variations will have little or no effect on the structure of the guitar.  I use the center of the dovetail and the center of the end wedge to find this line.  Hopefully this is also the "true center" of the guitar as well.

4.                    Mark location of back braces on ribs/linings.  

All of the back braces are tucked into notches in the linings.  This serves an important structural purpose in that the braces are much less likely to come separated from the back.  There is an esthetic issue here as well.  Many knowledgeable buyers will look at this "joint" and if it is sloppy they will see this as a indication of workmanship in areas they cannot see.  So, do it well.  I have found that when I lay the back on the ribs I can fit a very thin saw blade along side the brace and lightly mark the linings.  I do this for all the braces.  Then, after removing the back I can use a small fret saw to deepen those marks to the depth of the notches I will cut.  This serves two important purposes.  First, the saw cut is a very visible line to rout to in cutting the notch.  Second, because of the saw cut, as the router gets close to the cut the last bit of wood will simply drop out, leaving a very clean cut.  

5.                    Notch linings for braces.  

 I use a laminate trimmer (a small router) to cut the notches.  I set it to a depth equal to the thickness of the brace at this point and the notches will fit perfectly.  If, on careful inspection one or more notches do not fit perfectly, I use a small file to adjust them.

6.                    Trim back center strip to exact length between neck block and end block.  

With the braces carefully fit into their notches in the linings, I flip the guitar over and mark the center seam strip where it meets the end blocks.  I trim to this line.

7.                    Carefully inspect for fit and centering.   

Remember, this process will effect the final appearance of the guitar.  If the back is not centered it will be glaringly obvious.  If the braces do not fit well, that too will be noticed.

8.                    Lightly Coat linings and end blocks with glue.  

I glue my backs on with Titebond.  A fairly light coating is all you need and will help to avoid excessive glue squeeze out. 

9.                    Place back on ribs.  

Again, pay careful attention to centering the back.

10.                 Carefully inspect for fit and centering.  

Again, be careful.

11.                 Clamp ribs to back.  

The issue here is how to apply uniform clamping pressure to the back.  I use a domed form (like the one I use to sand the arch into the back.  I cut this roughly to the shape of the guitar and apply a thin layer (1/4") of closed cell foam rubber (weather stripping) to the perimeter of the form.  I then invert the ribs/back onto this form and can then clamp the ribs easily to this sandwich.  (Photos here).  For convenience I mount the form onto a swiveling holding device so that I have easy access to place the clamps.   I prefer this method because it allows a good view and access to the inside of the body so that I can clean up any glue squeeze out.  

Another way to do this is to place to top side of the ribs on a flat work board and use either clamps or rubber bands to apply clamping pressure to the back.  An alternative to rubber bands is thin bungee cord.  

12.                 Carefully inspect inside and clean/remove any glue squeeze out.  

Do this carefully.  Potential customers will see bits of glue as an indication of sloppy workmanship. 

13.                 Set aside to dry.  

Titebond is generally safe to unclamp after 30 minutes but when there is any tension involved, as there is here,  I wait at least an hour.

14.                 When dry, trim back to profile of ribs.  

For this I use a piloted laminate trimmer bit in my router.

15.                 Carefully inspect interior and clean/fix any glitches.  

Attention to detail is very important - be careful.

GLUE TOP TO RIBS

  1.                    Locate Centerline of ribs on both end block and neck block.  

As with the back this is important, although for the top centering is structurally important as it is essential to your bracing pattern. 

2.                    Locate top on ribs, verifying centering and correct front to back location (to ensure that bridge will fall over bridge plate.  

I have recently started drilling a 3/16 hole in the top on the centerline and a corresponding hole in the neck block.  I use a small wooden dowel or nylon rod to hold this end of the top in place.  (The fingerboard extension will hide this.)  This makes locating the top much easier.)

3.                    Mark front edge of soundhole on ribs.  

The next few steps are part of a process I use to "fix" a chronic problem with guitars. For a steel string guitar to work properly, it must have a reasonably tall bridge (5/16 - 3/8") and a reasonable amount of saddle protruding above the bridge itself.  (This facilitates the string leaving the back of the saddle at an angle (string break) which helps to put the correct amount of tension on the top.)  However in order to do this the neck must be angled back from the plane of the top.  This in turn leads to the fingerboard having a  downward bend at the point where it meets the body. and this in turn creates problems with setting the action correctly.  So, what to do???   One possible solution, adopted by many makers is to slightly dome the top (to about a 25' radius).  Properly done, this will eliminate the turn down of the fingerboard at the body.  Some builders also feel that a domed top will sound better.  

However, there is another way, which I have chosen to use (and which, truth to tell, I borrowed from Jim Olson). This involves leaving the top flat (mostly) and cutting a small wedge from the ribs starting at the soundhole and extending to the neck end of the body.  Properly done this small wedge will result in a top angle (for the portion of the tope where the fingerboard sits)  which exactly matches the back angle of the neck and will result in the fingerboard NOT bending at the body.   

To do this I start by marking the ribs at the point where the "wedge" will start - and this is at the top of the soundhole.

4.                    Prepare ramp to guide router for removal of “wedge” from ribs.  

I use a router to cut this wedge out of the ribs.  To do this I have prepared some tapered ramps which mount on the mold.  These tapered ramps have a carefully calculated angle (calculated by the age old technique of trial and error) which will guide the router.    The router itself is mounted on a long board that spans the width of the ramps.

5.                    Carefully adjust router to trim correct “wedge” from the ribs.  

Once the ramps are in place I carefully adjust the dept of cut of the router so that it just skims the ribs at the point marked in the last step, and cuts deeper as it goes towards the neck block.  The deepest point of the cut (i.e. of the wedge) is at the neck block and is about 1/16 - 3/32. 

6.                    Trim ribs.  

Once the set up is correct the cutting of the ramp on the ribs is quite straightforward.  After cutting with the router I lightly sand the top of the ribs to ensure a good glue joint.

7.                    Again, carefully locate top on ribs.  

I use my locating dowel at the neck block and carefully mark the center line of the top on the end wedge.

8.                    Mark location of X brace ends and fingerboard braces on ribs.   

This is done the same way as I did for the back braces.  I inset the ends of the X brace and the two braces under the fingerboard.  All the rest of the top braces are tapered to a very fine edge just short of the linings.  I do this in an attempt to achieve a balance of strength and flexibility at the edge of the top.  If the major braces are not inset into the linings, sooner or later the top will crack at these points.  Insetting the other braces does not seem to add strength and does seem to impede tone.

9.                    Notch linings/ribs to accept braces.  

This is done the same as the notches for the back braces.

10.                 Carefully trim remaining braces to fall just short of the linings.   

For the reasons mentioned above.

11.                 Carefully dry fit to ensure correct centering and location.  

This falls under the measure twice, cut once rule.

12.                 Lightly coat linings and end blocks with glue.  

Use glue sparingly.  You want a good strong joint but no excess squeeze out.  This raised an interesting point.  As noted above, I glue the braces onto my tops with hot hide glue.  It would seem natural to glue the top to the ribs with hide glue.  However, I have not found a way to do this because hot hide glue begins to gel (and loose effectiveness) after about 30 seconds.  I simply have not figured a way to glue on a top this fast - so I use Titebond for this joint.  

13.                 Place Top on Ribs.  

Measure twice cut one - so be very careful about location and centering. 

14.                 Place face down on a Work board designed for “wedge.”  

I have made a work board for this purpose.  It is essentially flat but has a small built up section for the  neck end of the body which matches the wedge cut out of the ribs.  This helps to ensure that the wedge which I so painstakingly cut into the ribs will still be there in the finished body.

15.                 Clamp top to ribs till dry.  

I use a variety of cam clamps and big C clamps (at the neck and tail blocks.)  The photos show that I have my work board mounted so that it is elevated which facilitates placement of the clamps.

16.                 When dry, trim top to ribs.  

I use a router with a laminate trimming cutter (ball bearing guided).

17.                 Sand ribs to smooth out shape and flatten sides.  

This is a fairly delicate, but essential step.  Once the box is together I sand the ribs on a 6" belt sander.  This helps to smooth out any unevenness in the shape or cupping in the ribs.  Obviously you can't do too much with this or the ribs will get too thin, but with a careful touch it is actually quite easy and significantly improves the appearance of the body.  

Continued on Next Page!!!!

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