Acoustic Guitar Construction

For some truss rods I see options for shorter versions listed for 12-fret necks - often in the 12.5" range, rather than the 14-15" range for most truss rods.

Ken, I know you are a fan of the Martin single action aluminum u-channel rods, LMII offers one in 15.15" length.

What truss rods do you guys recommend for 12 fret neck? Mortis and tenon neck joint.

Thanks for your help.

I use the long and short two way rods from the Martin Factory as well --- they are "beefy" and I trust that Martin has done their research so as to avoid warranty claims.

Ken,

I'm not seeing short u-channel aluminum truss rods from Martin or Stew Mac - only what I would consider to be 14 fret lengths about 14-1/4"

Is there another source I should look to for an appropriate length u-channel Martin style truss rod for use in short-scale 12 fret necks?