DASR FlexStrong Compression-Tension Truss Rod installation advice

[SVR88]

Hello,

I'm new to the forum here and I've read multiple posts on truss rod designs and how they function. I've always used Dual-Action rods, but I'm looking to change my design to a single rod and came across the DASR FlexStrong Compression-Tension Truss Rod from Allied Lutherie. They looked really nice, and I figured I'd try them on the next couple of builds.

I've read all the posts where Bruce Johnson explains the installation of his DASR rods and how he uses a curved bottom slot to install them. Now, the installation guide provided by Allied Lutherie states that the rods need to be installed at an angle without a curved slot. From what I've read, I'm leaning toward a curved slot that provides some built-in tension and will allow me to build any sort of neck profile—the curved slot being beneficial for slimmer necks.

My question here is: will these rods also work with a curved slot, or is it best to follow the installation guide and stick with the angled slot?

I hope some of you can shed some light on this matter, and I look forward to learning from more experienced guys.

 

[Bruce Johnson]

Hello,

I'm new to the forum here and I've read multiple posts on truss rod designs and how they function. I've always used Dual-Action rods, but I'm looking to change my design to a single rod and came across the DASR FlexStrong Compression-Tension Truss Rod from Allied Lutherie. They looked really nice, and I figured I'd try them on the next couple of builds.

I've read all the posts where Bruce Johnson explains the installation of his DASR rods and how he uses a curved bottom slot to install them. Now, the installation guide provided by Allied Lutherie states that the rods need to be installed at an angle without a curved slot. From what I've read, I'm leaning toward a curved slot that provides some built-in tension and will allow me to build any sort of neck profile—the curved slot being beneficial for slimmer necks.

My question here is: will these rods also work with a curved slot, or is it best to follow the installation guide and stick with the angled slot?

I hope some of you can shed some light on this matter, and I look forward to learning from more experienced guys.

The DASR FlexStrong Compression-Tension Truss Rod is a Single Rod design, which has right hand threads on one end of the rod and left hand threads on the other. When you turn the actuating head, the whole rod rotates, which draws the two anchor blocks toward each other, or pushes them apart. That's how it gets the double action.

This design of truss rod is intended to be installed in the neck in a straight slot, down as low in the neck as you can get it. I wouldn't recommend installing it in a curved slot. Rotating the rod inside a curved slot would take a lot of extra torque, because the rod is being forced to bend continuously as it goes around. That would reduce the amount of force the rod could apply to the neck before the rod would shear off.

in DASR designs like mine, the rod doesn't rotate. Fitting it into a curved slot doesn't increase the torque needed to adjust it.

 

[SVR88]

The DASR FlexStrong Compression-Tension Truss Rod is a Single Rod design, which has right hand threads on one end of the rod and left hand threads on the other. When you turn the actuating head, the whole rod rotates, which draws the two anchor blocks toward each other, or pushes them apart. That's how it gets the double action.

This design of truss rod is intended to be installed in the neck in a straight slot, down as low in the neck as you can get it. I wouldn't recommend installing it in a curved slot. Rotating the rod inside a curved slot would take a lot of extra torque, because the rod is being forced to bend continuously as it goes around. That would reduce the amount of force the rod could apply to the neck before the rod would shear off.

in DASR designs like mine, the rod doesn't rotate. Fitting it into a curved slot doesn't increase the torque needed to adjust it.

Hi Bruce,

Thank you for explaining the concept to me; it makes much more sense now. In the single-action rods and your designs, the nut tightens against a stop, straightening the rod. I never thought of it that way.

I'll stick with the angled slot and make sure to angle it as much as possible. The angled slot is just to provide extra leverage, am I right? So, the larger the angle, the better it will function?

 

[Bruce Johnson]

Hi Bruce,

Thank you for explaining the concept to me; it makes much more sense now. In the single-action rods and your designs, the nut tightens against a stop, straightening the rod. I never thought of it that way.

I'll stick with the angled slot and make sure to angle it as much as possible. The angled slot is just to provide extra leverage, am I right? So, the larger the angle, the better it will function?

The important thing isn't so much the angle, but the depth of the slot. This type of truss rod should be set down deep in the neck. as close to the back of the neck as you can. The farther it is below the fingerboard glue line it is, the greater mechanical ratio it will have. And the more force it can apply to the neck to bend it.

 

[SVR88]

The important thing isn't so much the angle, but the depth of the slot. This type of truss rod should be set down deep in the neck. as close to the back of the neck as you can. The farther it is below the fingerboard glue line it is, the greater mechanical ratio it will have. And the more force it can apply to the neck to bend it.

Got it, I'll bury the back end as low as I can. Thanks again for taking the time to respond, it really helps me learn from experienced people like yourself.