Reverse drilling spade bit

[Taffy Evans]

Hi, here is a very simple idea I came up with for drilling a countersink hole inside a guitar.

At times when doing a repair regarding heal repairs or neck resets I have often converted the neck attachment to a bolt-on method. To make the repair look neater I always counter-sink the bolt head into the neck block. This is not possible when the guitar is complete, so I do as shown in the photos, the cutting edge is on the back of the blade at the shaft end.

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Cheers Taff

[kiwigeo]

Would definitely be cheaper than the fancy set of aircraft spot face cutters I ended up buying! Nice one Taff

[Robert Gleason]

Is that just a square cutting edge on the back of the bit or sharpened similar to the front of a spade bit? Thanks, Bob

[Taffy Evans]

Hi Bob, thanks for looking in, yes I filed a cutting edge on the back like that on the front. The shaft that goes through the hole replaces the locating point that is normally on the front and stops the bit from skating around. I am just wondering if a similar bit of a suitable size could be used to countersink the washers used on tuning machines on the front of a peghead, for a neater look. I'll give that a try. I may need to incorporate the cutting-edge that has scribing blades on the outside edges. I hope that makes sence.
Taff

[Robert Gleason]

I don't like seeing the bolt at all, so I cover the countersunk bolt head with a separate piece of wood with a simple inlay in it. That is stuck to the neck block with the 3M double stick that is used on pick guards. That will be a bit of a mystery for future repair people because they won't know there is a bolt there, but I just don't like seeing the bolt. I'm thinking of going to a magnet to hold on the bolt cover.
The first time I encountered a bolt on neck was probably 30 years ago on a Taylor 12 string. In those days I had a guitar repair shop in town. I prided myself on being able to do neck resets when other repair people would not do them. Taylor used a paper label to cover the bolt back then, and I just assumed it was a dovetail joint. I steamed that joint for hours! It did loosen up and the joint became wobbly, but obviously never came off. You can imagine my frustration, let alone the fact that I had promised the neck reset in a reasonable amount of time. I finally had crushed the neck heel wood enough for me to figure out that it was bolted and removed the paper label to expose the bolt. Might have even been 2 bolts, I don't remember. Another lesson of many unforgetable lessons!-Bob

[Taffy Evans]

Hi Bob, I recall my first use of a bolt-on neck, maybe twenty years ago, and it was the start of my use of that method on my future builds.

I had to do a reset on one of my earlier builds, the guitar was twelve years old, and the tenon used had dowels down the sides of the tenon glue line. Short of removing the fingerboard and drilling the dowels out, I could see no other way to remove the neck but to saw it off at the heel. This led me to devise the bolt-on method I use today. I agonised about using bolts, I had seen them used on some antique instruments but not on modern-day instruments. It all worked out fine. Then soon after I saw reports that Taylor Guitars was using bolt-on necks, I felt better about them from then on. I have always used the furniture assembly flathead bolt with the Allen key recess, and they are gold colored so do not look so agricultural.
Taff