Brackett Instruments
Handmade acoustic guitars
Grover NC
This is page 2 of a pictorial essay of a build. The guitar will be an all Koa Mini Dread when it's finished. I've got a new video camera. There's a video on the 1st page. I'll do a few more videos before it's completed. Click on the images for a bigger view.
Disclaimer: The internet is full of bad information on guitar building. Some people build 1 or 2 guitars(or less), then start posting information, and videos on how to build them. This is my 25th. I'm not pretending to be an expert, and this isn't intended to be a "how to build a guitar" page. It's just the way I do it. Feel free to contact me with any questions or comments.
The fingerboard is bound with Ebony, with a Bloodwood purfling line.
I use the completed fingerboard to locate the soundhole and rosette. Using the actual fingerboard helps avoid mistakes. I use a foredom tool and circle cutting attachment to route the rosette channel.
I thickness my tops by deflection testing. You get more consistant results than just making them a pre determined thickness. I'm looking for a certain amount of deflection at a certain pressure. The indicator is zeroed. The weight of the scale, and the block the scale sits on it all accounted for. The numbers are determined by body size and style, string tension, and tone desired. Too thick/stiff the guitar is dead, too thin and it will loose focus. This top is really stiff, for wood with some figure. The thickness is ~.085. (sorry for the bad picture) A couple thousants of an inch will really affect the stiffness. A top needs to be light, and stiff. Deflection testing also help eliminate weak tops.
Now, since the top is thicknessed I draw an outline of the inside, and outside of the ribs on it. This helps with locating the braces. The end of the braces that are in front of the bridge will be tucked into the linings. Rotational forces try to rip these braces off. Tucking them make the top more stable. The braces behind the bridge will end right at the linings, but won't be tucked. Rotational forces aren't trying to rip them off. It also helps loosen up the top, for a more open tone.
After I mark the inside of the linings on the top I mark the sides in the mold (so I can put them back the same depth, the geometry is right now) I then remove the ribs. I cut, and re enforce the sound port (if the guitar is getting one). This is a thin piece of spruce. It looks good, and does the job. I seal the inside of the sides with shellac so the glue isn't exposed on the cloth side re enforcement strips. It looks good too, but I know no one would actually look inside a guitar LOL
I should have pictured the relationship between the fingerboard and the top/soundhole/rosette sooner. I don't use any plans, or patterns. I lay out the bracing and soundhole location on each guitar. That's the way a custom should be shouldn't it?? Using the fingerboard I locate the upper transverse brace (the brace in front of the soundhole). I also locate the bridge. I draw the outline of the bridge on the inside of the top, and locate the rest of the braces off of it. The relationship of the bridge, and the rest of the braces has a big influence on the tone.
The intersection of the X brace is a very important joint. It needs to fit. I make it and cut slightly undersized with a small hand saw. I do the final fitting with a chisel and file.
I use hot hide glue for all the bracing. It's super strong, and dries extremely hard. Bottled glues are strong, but not as hard....kinda like having tiny sponges in between all the joints. I pre heat the parts for stronger joints, and longer working time. Hot hide glue jells at 95 degrees. The joint has to be together and clamped before it jells. Some builders (and pretty much all big companies) use bottle glue because it's easier. I think using hot hide glue is worth the extra effort. After the upper transverse brace and X brace have dried I install the bridge plate and tone bars. I shape the braces to voice the top, instead of just installing some kind of pre shaped braces. This allows me to get the most out of every guitar.
