Where there's a will there's a way so I'm sure you can reinforce it. Some pictures would be helpful though.
Hi, remove the fingerboard route a slot and install a bar. You probably can't do that, so I'd send it back. A neck held on with dowels is also an unreliable joint, in my experience.
For such a short neck to flex without string tension is a concern for me. I would think the timber is wrong, the grain is wrong direction and/or fretboard is of a unsuitable timber with Wrong grain direction.
I have repaired both the faults mentioned above, not cheap repairs, but I'm set up for that.
My advice....contact supplier.
Yes pictures would help . and check to make sure if it is actually the neck wood bowing , or if its more of a pivot point issue at the neck joint . the strongest truss rods in the world wont fix a pivoting joint issue . or a box curling up after the joint. or bend in the box sidewall. etcetc ...
Here's a few pics. An idea I had was to screw in a wood screw into the lowest portion of the exposed heel in the 1st pic ,directly against the channel I drilled out and cover it all with epoxy. Hope I'm explaining this visually enough. Any suggestions are welcomed. Thanks.
I think it’s needs the neck support to travel through the box there’s not enough support with the small block in your picture ,just my humble opinion mate .
The pics do help . one possibility could be that your heal cut ( as straight as it may be) . might need adjusting or cut at a slightly different angle . either due to the side wall being off, or the necks actual shape .( rough example in pic a bit exaggerated .) . That can also give you a downward neck degree , which some folks do on purpose for more sound and volume .. and with your high bridge would most likely solve 2 problems . hopefully all your stuff is not glued down yet ? (fretboard on box, bridge etc?
(it could also just be being pulled tight on the top end due the one screw you already have in there . in which case don't cut till you try another anchor screw on the bottom )
still kinda hard to see/ know what going on there .. so dont jump to any fixes untill you explore more options here . And start with the easy / undoable fixes first .
When the box is closed does your heel block make good contact with the back of the box.?
Ok, the photos do help. The neck grain looks to run correctly, the fingerboard is substantial, so I assume your comments about "flex" to be associated with the neck body/box joint.
I feel that if you carry that block through the box it will dampen the soundboard too much if glued to the top. You only have low tension nylon strings to drive it.
I would say that, that block size would work if secured to the front the back and the top. With screws holding the neck as you mentioned. I've used this method using bolts or screws.
The neck looks quite substantial so I'm guessing you don't mean the neck itself bending like an archer bow, but that the neck/box joint is flexing.
and if so, you need a bigger mounting block that contacts more of the soundboard and the side of the box where the neck mounts, more points to transfer the stress to the whole body and not a small point
and 2 mechanical connectors (dowel, wood screw, bolt into threaded insert) through the block into the neck's heel, as far apart as you can. Much like a tripod, the wider the spacing the more stable it is.