Build Thread - McKnight Mini Mac (SJ) !

[Mary]

Our little girl with her little girl - It's always a welcomed moment to take a kid break.

[GCWaters]

Forgive me if this is a stupid question, but are the two rods from the neck block there to hold shape during construction?

[Neil K Walk]

That is my favorite headstock shape!

As for the carbon fiber rods, IIRC it's for reinforcement in the area to prevent potential twisting and reduce the likelihood of breaks in that area. The backstrap on the back of the headstock also does somewhat too IIRC.

[Tim McKnight]

Originally Posted by PhilipY

Originally Posted by GCWaters

Forgive me if this is a stupid question, but are the two rods from the neck block there to hold shape during construction?

If you are referring to the picture above they are called buttress braces. Two hollow carbon fiber tubes attach to the top of the neck block and run diagonally down to the apex of the waist bend, which by the way, is the stiffest area of the rim. Our neck attaches to the neck block by glue and two bolts. Due to the string tension exerted on the neck, it is putting a rotation moment on the neck block trying to rotate it. On a conventional rim, that rotational torque will deform the sides and flatten the back’s arch over time which in turn allows the neck to rise in turn raising the action and eventually necessitating a neck reset. Buttress braces stop that rotational torque and hopefully eliminate the need of a neck reset. I’ve been using these buttress braces for ~20 years and have never seen or heard any reports of the action raising on our guitars.

[GCWaters]

Originally Posted by Tim McKnight

If you are referring to the picture above they are called buttress braces. Two hollow carbon fiber tubes attach to the top of the neck block and run diagonally down to the apex of the waist bend, which by the way, is the stiffest area of the rim. Our neck attaches to the neck block by glue and two bolts. Due to the string tension exerted on the neck, it is putting a rotation moment on the neck block trying to rotate it. On a conventional rim, that rotational torque will deform the sides and flatten the back’s arch over time which in turn allows the neck to rise in turn raising the action and eventually necessitating a neck reset. Buttress braces stop that rotational torque and hopefully eliminate the need of a neck reset. I’ve been using these buttress braces for ~20 years and have never seen or heard any reports of the action raising on our guitars.

Very interesting—thanks!!

[PhilipY]

To my eyes, the guitar is almost completed. So talked to Tim about this, and he said we are just halfway through the whole trip.

Haha I know that will be a long waiting time, and actually, I enjoy this. To see a guitar comes out of the luthier's hand from the woods is an experience that I can never get from buying a factorial guitar.

Here are just some new pics for the bridge, peghead, and neck.

[Carpinteria]

Coming along very nicely! I have a question about the neck. It looks like you have graphite rods flanking the adjustable truss rod, but they don’t appear to extend the full length of the neck. I’m curious about the thinking behind the setup. Thanks! Dave

[cigarfan]

Coming along. Almost into the paint drying period. Exciting!

[Guitars44me]

This is truly Coming along very nicely!!!

Go Tim, go. And Mary too.

Happy Saturday

Paul

[PhilipY]

Hi guys, these posts will be quite long.

I recently got some professional explanations from Tim about the guitar-making process, and I would like to share them with you.

Two way adjustable truss rod:



Truss rod glued in place using Silicone adhesive:



The top image shows two black carbon fiber bars. These are inlet and glued into the neck to provide additional stiffness to the weakest area of the neck shaft, which is just below the nut.
Bottom image is a template that is used to drill two holes on the underside of the fretboard which locates the fretboard in the correct position on the neck during the glue up process.



Drilling the two holes on the bottom of the Fretboard:



Marking the end of the Fretboard extension to trim to final length:





Tim is sanding the shape into the bottom of the Fretboard extension. He says that the shape will be a mirror image of the top line of the peghead. This shape will also be duplicated on the belly of the bridge as well which ties all three into the overall design of the guitar.



Fretboard extension is all done:



Ebony fretboard and two strips of binding:

[PhilipY]

Due to the limit of the number of pics I can upload in one post, here we have more about the fretboard.

Gluing the bindings onto the edges of the Fretboard:



Getting ready to epoxy glue the Fretboard onto the neck shaft:



Glue goes on:



Glue is spread evenly:



Then it’s clamped up to allow the glue to cure overnight:



A day later the clamps are removed and the neck is sanded to the final shape:



The face of the Fretboard is marked for the mother of pearl micro dot position markers:

[PhilipY]

More about fretboard...

Next the Fretboard edge is marked to accept the same dots:



Tiny holes are carefully drilled:



Tiny MOP dots are fit into the holes:



After the glue dries the dots are filed flush with the wood surfaces:



The wood is then pore filled with a thick paste. The paste sinks into any open grain pores of the wood:



Using a material Tim calls “Hog Filler”?



After the paste is partially dry he wipes the excess paste off leaving the pores of the wood filled and the surface nice and smooth:

[Neil K Walk]

This image made something click in my addled brain about a problem I've been having with necks being way too beefy. Thank you for positing it.

[Tim McKnight]

Originally Posted by Carpinteria

Coming along very nicely! I have a question about the neck. It looks like you have graphite rods flanking the adjustable truss rod, but they don’t appear to extend the full length of the neck. I’m curious about the thinking behind the setup. Thanks! Dave

Hi Dave,
I used to run the carbon fiber bars the entire length of the neck. However, they made the neck too stiff and I had difficulty adjusting relief into the neck shaft. Now I only run the CF bars from the peghead, under the nut and a few inches into the neck shaft. This reinforces the nut area which is the thinnest and weakest area of the neck. The truss rod is able to do its job of adjusting relief in the neck.

Originally Posted by Neil K Walk

This image made something click in my addled brain about a problem I've been having with necks being way too beefy. Thank you for positing it.

Hi Neil,
I rough most of my necks out to a “general shape” with our CNC router. After the fretboard is glued down then I do the final shaping of the neck with a small hand plane and sometimes it requires a rasp but usually I can shape the profile and thickness using 180 grit sandpaper on my random orbital sander. I hold the sander in my right hand and then roll the neck with my left hand while rolling the sander with my right. Both are moving and rolling in unison. It’s difficult to put into words but I can show you in person in June during the McJam. It takes me less than 10 minutes to finish the necks shape and profile, once you get the hang of it

[PhilipY]

Here is the recent update from Tim. Gratefully I received his explanation of each step.

Masking off Fingerboard extension with .001” thick Frisket Film:




Trimming excess masking with a sharp surgical scalpel:




Masking bridge gluing surface of the top:



Laying out and squaring bridge location to the exact centerline of the guitar:



Drilling bridge locating holes: