There's nothing better than a well set up router table. Since my neck sides are not straight in relation to the centre where the rod needs to go, I tapered a piece of Birch to correspond with the neck. Two holes were drilled halfway through and small screws inserted until they emerged on the mating face by a couple of mm. This was then pressed into the side of the neck and the rearmost screw advanced in a couple of turns since the end is to be cut off anyway. The centreline measured bang on 70mm from the edge, so I set the fence accordingly, took a test cut on some scrap and measured any difference. None....bang on. After marking the endpoint of the cut (minus the radius of the cutter) the neck was slotted in 1-2mm increments until a depth of 10mm was achieved. This is when the photo was taken.
To fit the adjuster and welded block end in, the fence was tapped with a hammer (in the background, actually) on one side one millimetre to achieve an offset at the centre of 0.5mm. I took the second cut after tapping the fence back 0.5mm the other side of 70mm. A 10mm bullnose cutter replaced the straight flute bit and was run through the centre (after resetting the fence) to create a rounded bottom for the adjuster and a round access hole.
After the rod was checked for fit, the glueing surface of the neck was run over the jointer with a 0.2mm depth of cut (I believe it too....very fine cut), the rod checked again for fit and siliconed in place with a strip of masking tape to keep it from being knocked out. The end of the neck was cut to length and the waste used along with a piece of Ebony to fashion a plug to fit over the truss rod adjuster. As of a couple of hours ago, this was glued in place and is drying overnight before I pick up the work again on Thursday.
Next I need to slot the fingerboard, taper it minus a couple of mm and glue on some more Wenge to self-bind the board. I am not going to go for a full semi-hemi job on this one since I am using stainless steel wire. All things being equal, the board should be being glued on by the end of play Thursday. From thereonin the neck will only be getting trimmed flush as the body needs work....