Rickenbacker 4003 Action

[Mr. Foxen]

Truss rod engineering stuff:

Here is the original truss rod:


Between the bogies on a load bearing flatbed car. Note it doesn't run parallel with the bed but has spacers so it is angled at the ends , this is key.

In a Fender style arrangement, since Fender had a pretty good grasp of engineering, at the headstock end the truss rod is close to the fingerboard side, but the other end is toward the back, additionally the neck is made flat but intended to have a slight curve under tension, this arrangement means the force exerted by tension on the rod opposes that of the strings in attempting to curve the neck back the opposite way. In a Rickenbacker neck, the rods run parallel with the fingerboard, much easier to route that way, the whole thing is flat and the channel depth even, but it means the rods just put the neck under compression rather than opposing string tension, meaning simply tightening them has effects dependent on the properties of the piece of wood, something Fender engineering always sought to eliminate as a variable, and thus requiring the neck to be set in place before applying compression to hopefully hold it there.

[martthebass]

[quote name='Mr. Foxen' timestamp='1369185381' post='2086115']
Really? The neck collapsing into the pickup cavity is pretty notorious. The whole thing where the moved the neck pickup was supposedly to address it, although in the ones I've seen, the route is still oversized so didn't really address the weak point as well as it should have.
[/quote]

Sorry to be pedantic but I thought you meant a physical dislocation of the neck join...not a 'folding up' due to structural weakness caused by excessive routing. In this case it isn't the joint that's at fault but the integrity of the neck through block itself ;-)

[Mr. Foxen]

[quote name='martthebass' timestamp='1369224109' post='2086471']
Sorry to be pedantic but I thought you meant a physical dislocation of the neck join...not a 'folding up' due to structural weakness caused by excessive routing. In this case it isn't the joint that's at fault but the integrity of the neck through block itself ;-)
[/quote]

The design and construction of the bass is at fault. Routing a hole at the point where the neck meets the body, which effectively cuts through the neck block, the glue at the joint failing due to not much earea taking the stress is the actual failure that allows the neck to shift.

[MiltyG565]

My understanding of the word "truss" was that you reinforce something with triangulation. Having a truss rod run perfectly parallel to the thing it is supposed to strengthen is defeating the purpose to a degree.

[iiipopes]

[quote name='Mr. Foxen' timestamp='1369225552' post='2086505']
The design and construction of the bass is at fault. Routing a hole at the point where the neck meets the body, which effectively cuts through the neck block, the glue at the joint failing due to not much earea taking the stress is the actual failure that allows the neck to shift.[/quote]Um, Rickenbacker basses are neck-through. There is no joint. Your observation is valid, however, from the point of view that the wood can be cut too thin by the pickup routing at this point. Oh, BTW - Gibson guitars, especially first generation Les Paul SG models, had the same weakness, and guitar necks would actually fall apart until the tenon was redesigned.

[Mr. Foxen]

There is a joint between the wings and the neck, since the neck is effectively sawn through at the point where it meets the body, the join between the wings and the neck is the failure point. Hence being able to see the cracks there on failing ones.

Edited May 22, 2013 by Mr. Foxen