Wren Build Thread ... last of 2018 ... Sitka/Koa

[Halcyon/Tinker]

Love seeing the physics in action!

[SJ VanSandt]

Originally Posted by David Wren

Hey Stan ... Trevor Gore has forgotten more than I'll ever know about this technique. I think of adding mass to the sides as a way to nudge the main resonant frequency of the top (and since everything is coupled, all the other main frequencies) without affecting structural integrity (shaving braces) or altering the response (adding mass to the top) ... and it can have the byproduct of moving that monopole node closer to the outside of the guitar (making the pumping action of that mode more efficient). I use magnets as a temporary way to see what effect more mass will do to the sound of the instrument and where it takes the main resonant frequencies (and by extension, if excessive admittance manifests on any notes associated with the main resonant frequencies). If more mass on the sides is ultimately decided on, usually you would glue in a two or four wood side struts with small bolts on them to accept steel washers of some description.

Ah, I get it - the magnets allow you to add more mass temporarily to see what works best, without making structural changes. That's clever! Thanks, David.

[David Wren]

[David Wren]

Originally Posted by Halcyon/Tinker

Love seeing the physics in action!

Hey Ed ... thanks for watching this thread!

[David Wren]

I'm sure it seems odd to have a neck angle jig made of wood ... but I've used the same one since 1975 and it hasn't moved a jot!

[David Wren]

[j. Kinnaird]

love your shop David. Very interesting technique on adjusting the neck angle. Care to elaborate on that?

I must say that the heel seems unusually large

[David Wren]

Originally Posted by j. Kinnaird

love your shop David. Very interesting technique on adjusting the neck angle. Care to elaborate on that?

I must say that the heel seems unusually large

Hey John ... I love my shop too ... HA!

My neck angle technique (i.e. the technique I learned from Jean Larrivee in the early seventies) relies on a few very basic small jigs only.

I basically sand the end of the neck to the appropriate angle (using a straight edge to check the side to side angle, and that basic wooden jig to get the appropriate tip-back angle) ... then screw a piece of plexi to the end of the neck (tapered, since I use a dovetail ... rectangular if you want a tenon).

I then use a router table setup (clamp a piece of wood to the neck to maintain the side to side angle). When you route the dovetail on this router table setup, the proper angles are automatically transferred to the cheeks of the neck heel.

Not sure if that makes sense?

[David Wren]

[David Wren]

[David Wren]

[David Wren]

[TomB'sox]

I think hand carving the neck is my favorite part to watch and has to be one of the cooler parts to do I would think! Looks great.

[David Wren]

Originally Posted by TomB'sox

I think hand carving the neck is my favorite part to watch and has to be one of the cooler parts to do I would think! Looks great.

Hey Tom ... carving the neck has always been one of my favorite proceedures, that's for sure!

[David Wren]