tiistai 1. marraskuuta 2011

Brace shaping and back bracing

Top braces are now shaped and the rosewood bridge plate glued in 00-model. The J-OM model back received it's center seam reinforcement strip of spruce and bracing. The next thing is thickening the J-OM top down to 3mm, cutting the rosette and laying down the bracing pattern. Then it's side bending time, possibly before this year ends.
Making the internal bracing starts
with splitting the quality, straight grained
spruce brace wood
down to size.
Once the wedge is driven into the slab,
 it pops out with a clappy, happy sound.
The tool laying on the floor is "puukko"
(aka fisherman's/hunter's/carpenter's knife)
 - the thing us  Finns used to utilize for every
 walk of life from food supply to cooking to
 eating to making tools & toys to relating to
 neighbors & family to putting up a fire to warfare
and hunting to law enforcement to whatever you name.
 It's pretty handy to have a few at hand in
case of any need.

The grain must be straight and driving
pace slow, to make straight splits

Here the center seam reinforcement is glued down and
the braces are ROUGH split. Enter the plane!
Back brace bottoms are contour-sanded on my
high-tech contour-sander


The center seam is notched to house the braces


Go-baring again. This is such a handy invetion!


Back to the top. All the braces are there, but only
 part of them shaped. I use a sharp chisel in shaping.
 The largest braces are scalloped - meaning some material
 is removed of the brace to make the top lighter
and more flexible.
The bridge plate (3mm) is made of scrap rosewood.
 It's reinforcing the bridge area, as it has to resist
the pull of the strings for the years to come.
The grain goes intentionally a bit off axis,
 to prevent possible splitting from the
string ball ends.

Gluing the bridge plate with wooden cauls.
Finally all the braces are shaped too.



tiistai 18. lokakuuta 2011

Go-baring the top and some nice wood

Being a spare time hobby for me, luthiery hasn't caught much attention lately. Here's some latest activities over a pretty long period:

- preparing and gluing the top center seam for Jouni's guitar.
- preparing and gluing, re-preparing and re-gluing the back center seam for the same. The Ultimately Good Looking Cocobolo (UGLC) seems to be a very tricky wood to be glued. It's a very oily wood and seems to be rejecting almost everything I have to offer gluewise. It remains to be seen, if the latest trick'll do the trick.
- preparing top bracing for Jyrki's guitar. This has become a lot easier with the concave discs I made. I'll just simply put some sanding paper on the disc and sand the braces in right shape to fit the curvature of the top. Less guesswork, faster and more precise glue seams.
- Gluing down the bracing using the Go-Bar method, AKA AAWSIBTSP (Awful Amount of Wooden Sticks In Between Two Slabs of Plywood).

German Master Grade "moon spruce" and Mexican Cocobolo


Nice detailing in the wood

The sides have a distinctive pattern too


Laying down the bracing pattern for the 00-sized guitar. For some reason the lowest two braces run the wrong way in this picture 
Go-bar gluing the bracing - first all the rest of them

And then the center x-brace too. It took 26
 bars to get there, I believe. 

maanantai 26. syyskuuta 2011

Global rosette

Here's two shots of the 00-top with rosette installed. Top is european spruce, very stiff and nice looking stuff bought from a chinese seller through american ebay. Rosette with East Indian rosewood and  New Zealand Paua abalone is bought from a taiwanese seller in ebay. Put together in Oulu, Finland. Now figure that globalization out!

The rosette channel was cut with a dremel tool attached to a home made routing base. Two parallel runs was sufficient, as the rosette fits in a single wide slot. Soundhole was cut with the same tool, only deeper.

The rosette opening is a bit offset to get the grain direction right. The opening is nevertheless covered by the fingerboard.

This appears to be one of my cleanest rosette installations so far. Experience? Luck?

tiistai 13. syyskuuta 2011

DIY internal microphone

Amplifying an acoustic instrument is not an easy task. Picking just the strings isn't enough, because the body resonances are the ones that make the sound "acoustic". My take on the subject is going dual source. The guitars are equipped with a triple soundboard transducer (K&K Pure and JJB Electronics Elite). I like them, because they are pretty inexpensive and offer quite natural response through the frequency range. The dreaded "piezo quack", unnatural high frequency, usual in under saddle piezo transducers, is not so dominant in these soundboard/contact transducers.

Anyway, to add some "air", "naturalness" "whateveryouwannacallitthatsoundsbetter", I use an internal miniature electret condenser microphone. The two passive signals are routed out with a stereo 1/4" cable and into a Presonus Acousti-Q preamp/blender. It's got volume controls for both signals and very nice eq.

I thought I'd report an easy way to make a "gooseneck" condenser mic. This model works only with a preamp feeding 2-12V phantom power to the mic, thou. For a standalone version you'd need a condenser,  a resistor, a 9 volt battery and few inches more wire in addition.

A little sound clip: Dual Source -> Acousti-Q -> Firebox -> Garageband with a hint of EQ and reverb. The delay effect comes from Zoom A2 hooked in the Acousti-Q's efx loop
Gooseneck peeking through the soundhole
Here's the stuff needed to make a mic

Panasonic capsule and shielded cable...

...soldered together


The capsule's got two terminals, one for hot, one for ground. 

They provide a handy silicon sleeve for the capsule.


Heat shrinking tube...

...and some wire...

...shrunk together...

And attached to a metal paper clip...


...and we're ready! The clip attaches to a back brace nicely and is easy to place to an optimal spot because of the bendable shaft.

This unit provides the phantom power the capsule needs, mixes the two signals and more. It's got a vacuum tube too!

tiistai 6. syyskuuta 2011

Cocobolo back

Here's a few pictures of a nice cocobolo set I got for a birthday project. A friend's brother is turning 50 in 2013, and he's been given a gift of "process of making guitar". It's going to be a J-OM size (equivalent to Martin J & 0000 shape) with spruce top.


Which way to place the sapwood pattern?




torstai 1. syyskuuta 2011

Go Baring

Go Bar -method is a simple yet powerful way to clamp braces to the top/back plates with wooden/glassfiber rods. During spring and a bit of summer I built myself one (it's really simple too). Before this built I've been utilizing interiors of what used to be a kitchen cupboard, but it's floor gave in to the pressure so I had to make a more "professional" one. The hardest part is to make a concave mdf disc to arch the braces to achieve the wanted radius on top/back.

Finally I got to try the method today, and it seems really good. The braces are easily radiused with some sanding paper on the disc, and will exactly match the back when gluing on the same spot they were sanded.

Hope a few pics will explain it better.

The "cradle" for routing the concave disc. Behind it the actual Go-Bar system


the railway for the router, with proper radius sanded to it

and here we go. Takes a few passes to make it smooth.

...and is pretty dusty too!

And here is the Go-Bar system in use. The wooden rods provide the clamping pressure

Jyrki, here I come! Not too many months anymore

torstai 26. toukokuuta 2011

Small body planning

The word for the next projects (yes, there's going to be #6 & #7) is Small Body.
Martin's double o, 00, is going to emerge in 12 or 13 fret and 14 fret versions. Below you find three different plans - three interpretations on the same theme - two by Martin and one by Gibson.

Planing rosewood sides for the 00-28 style 12-fretter. 


Gluing the back plates together

Down middle is the original Martin 00-shape, with body-to-neck joint at 12th fret (like in classical guitars).  Up left is the Gibson interpretation of the Martin 00, with the neck joining the body at 14th fret. Gibson just moved the bridge up a few notches, leaving the body shape pretty much the same (note the roundness in the upper bout.)
Up right is the Martin 00 with 14 frets to the body. With the player's need to access upper frets, the 00 body was reshaped. The bridge sits higher on the lower bout (not in the middle of the "drumhead" anymore) and the upper bout has tighter curves as it's been shortened a bit. There's also a"hybrid version" with 13 frets to the body. Some think that's the optimal compromise soundwise, especially with the longer 25,4" scale. I'll see where all this settles.

The mold for the 00 12 (or 13) fretter.

lauantai 14. toukokuuta 2011

Tres hombres outside

I've made three guitars with the same mold. I call the body shape J-OM. It's a fattened (J=jumbo) version of the Martin classic Orchestra Model. The volume of the box is somewhat bigger than OM but smaller than a Dreadnought. As #4 happened to be around for a tweak, I decided to shoot some "family photos" just for the fun of it. Luckily, the sun was shining too.




Rosewood, koa and flamed sapele mahogany. The sapele has darkened quite a bit since it was born.