Making A Bridge With Hand Tools

no electrons sacrificed...

The classical guitar bridge is pretty simple: just a  rectangular piece of wood with some longitudinal grooves.  It's a pretty straightforward procedure with a table saw and/or router table - once the machines are properly set up you can run a lot of wood through and make many bridges in fairly short order (although it still requires some hand work). 

 However, you are no doubt asking yourself:  "how would Roy Underhill make a guitar bridge?"  Not to mention: how did Antonio de Torres, Manuel Ramirez, Santos Hernandez, et al. make their bridges?  (If any of these names are unfamiliar to you, please Wikipedia them.)  

The common thread there is the use of hand tools only.  Here are the tools I used to make the bridge in this post:

 

And here are the raw materials; a hunk of Indian Rosewood, a piece of bone, and a couple thin strips of veneer of contrasting colors:

The bridge can be thought of as two sections: the center part with the tie block and saddle, and the sides, or outer "wings".  While there are many ways to proceed, on this bridge I'm first separating the center part from the wings. The wings are lower than the center, so I'm creating a space to either side that will allow work on the center part of the bridge. 

I used a plow plane to create these grooves, but other tools could be used to achieve the same result.

 A fret saw is used to remove a couple this strips from the piece of bone.  These will be inlaid around the tie block.  Besides being decorative, the bone inlay prevents the strings from digging into the wood.  The thin veneer strips will be glued to one side of the bone strips - not necessary but looks nice.  The piece of bone that's left will be used for the bridge saddle.

  The excess width is sawed off using my indespensible custom-made Mike Wenzloff small rip saw.

The bone strips have been glued into a small recess around the tie block.  The corners are mitered, and it took a while to get the fit good!

 Shaping the wings and the ramp behind the saddle...

The string holes have been drilled (with the eggbeater drill) and some finish applied (oil varnish in this case).

 Here are a couple completed bridges, one showing how the bone saddle fits into place (of course it is only roughly shaped at this point).

Closing the Box

Meanwhile, Back to the Back...

The back braces have been radiused and are glued onto the back in a 'dish' of the same radius as the braces.  Since the back is so thin (approx. 2.3 mm) it will easily hold the curved shape after the glue dries, and a domed back is achieved.

Shaping the braces after they have been glued on...  This shows a carved brace (on the left), carving in progress (middle), and one not yet touched.

Ah, it occured to me that before the back can be attched, there must be some sides to attach it to.  I'm using a different method to bend the sides than the previous guitar (documented earlier in this blog), in which the side was pressed into a mold.  Here, a 'bending iron' is being used - the bending is done by hand, holding the wood against the iron until it is hot (and pliable) enough to bend.  While bending, the side is frequently referenced to the template to make sure it is shaped correcly.

 It's also important to check to make sure that the side does not develop a twist as it is bent, so it is frequently checked for square.

  Fast forward a bit, the sides have been installed into place, and the linings and tail block added.  Also (and very importantly) since the back is radiused, the linings, tail block, and foot have all been shaped to accomodate the radius of the back so everything fits nicely.  Oh, one more thing - you can make out small notches carved out of the lining (three on each side) - the back braces sit down into these notches.  OK, it's ready for the back to go on!

 The back is glued up and clamped.  This is the 'face down' method of assembly, which while having it's advantages, has the disadvantage of not being able to access the inside of the guitar through the sound hole to remove any squeezed out glue (before it dries).  When using this method, you have to be careful to get enough glue in the right places, but not so much that it creates globs of squeezed out glue inside the guitar (most unsightly).

 

Whew, clamps removed and a successful back glue-up.  Looking through the soundhole, you can see where the back brace fits into the notch.  Fortunately, you don't see (much) glue squeezed out...

 At this point it starts to look like a guitar! 

Next post: Making a bridge with hand tools.