New project - Terz-shaped 00-12

Dave Bagwill · Post by **Dave Bagwill** » Tue Nov 25, 2014 8:28 pm

I found a delightful shape for a new 00-12 - the shape is for a Terz guitar (a small guitar) so I made a copy and had it enlarged to around a 00-12 size, more specifically:
LB 15 1/2"
W 8 3/4"
UB 10 1/2"
Length 20"

I'll be using the Mega Mold for the build (which is why I bought one - I can easily try a new shape) - but for the bending form for my laminated sides, I had to reconfigure my existing KMG 00-12 mold. My new shape has a bigger bottom and a more rounded top than the KMG shape.

Then I measured the top material - AA Sitka from LMII - measured the thickness of each board in 10 different places and took the average; weighed each piece; measured the width and length; plugged those values into the Excel worksheet Brian Burns gives away; then did the actual deflections tests using the jig I build from Brian's plans, and plugged those measurements into the spreadsheet.

The wood tests okay, but just okay. It is sufficiently stiff, has a good stiffness to density ratio, and will respond well to bracing. Visually it is fine, some runout on what will be the unused portion, grain between fine and coarse somewhere. All in all a sufficient top to work with. I was always uncomfortable, not knowing if I was building an entire instrument around a top that I would have to fight all the way.

As a side note, the provided LMII boards tell me that their drum sanders need a little calibration - not way way off, but enough that a guy should know that they are not perfect, but not too bad. One side had measurements - 10 - that ranged from .143" to .152", and the other side ranged .146" to .154".

This is easy stuff to do, but does provide some information that might prove helpful. It is not 'advanced guitar making' or anything like that! - just a bit of added info. There are other tests to do as well.

I've attached pix for the curious.

Dave Bagwill · Post by **Dave Bagwill** » Tue Nov 25, 2014 8:36 pm

BTW here is a photo off the web of the Terz guitar shape that caught my eye. One interesting thing is that, when I made some templates, though it is designed for 12 frets, a 14 fret neck places the bridge at a good spot as well. I think because the lower bout is so fat.

John Parchem · Post by **John Parchem** » Tue Nov 25, 2014 9:28 pm

Looks like it will be a fun project! Interesting to see the use of your deflection jig. I might start deflection testing my braced tops, just for informational purposes. What is the scale length for the guitar?

Dave Bagwill · Post by **Dave Bagwill** » Tue Nov 25, 2014 10:59 pm

24.82"

John Link · Post by **John Link** » Wed Nov 26, 2014 9:11 am

The outline shape of this guitar is very compelling. It has a definite "old timey" look about it and is strongly unified, that is, the curves flow smoothly from one to the other. An excellent choice.