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I'm building a mandolin and I use the mandolin drilling guide from StewMac. This guide clamps on to the back of the headstock and you drill your tuner holes with a 1/4" drill. They have some guide pins to make alignment easier. This guide works great. The problem, however, is that I still had to drill the concentric holes for the bushings. It turns out that the solution is simple and I'm kicking myself for not having figured it out several instrument ago.

After drilling the 1/4" holes, clamp a block of wood to your drill press. Put the 1/4" bit into the drill press and drill a deep 1/4" hole. Now remove the 1/4" bit and chuck in the proper bit for the bushing. In my case it 10mm. Bushings come in many sizes make sure you get the right one.

insert a 1/4" steel pin into the hole you drilled in the wood block. Push it in so that only 3/16" is exposed or so.

Place your headstock on the block of wood so that the pin goes into the back of the head stock at one of the tuner holes. Set the depth stop on your drill press or put tape on the bit. The larger drill is not perfectly aligned with the small hole. Drill you bushing hole.

Move the next tuner hole onto the steel pin and drill. Continue until done.

I know StewMac sells a special bit for Waverly tuners but that doesn't work for other brands.

It took me less time to do this than it took me to write the description.

Correction: "The larger drill is NOW prefectly aligned with the small hole." sigh

Correction: "The larger drill is NOW perfectly aligned with the small hole". double sigh

I don't know if it will work with the jig you use, but I always drill the larger hole to the proper depth first. Using a brad point bit, you will maintain a clean centre to guide your smaller bit.
If you need to drill in from both sides, a 1/16" pilot hole will give you a good centre from both sides.
A sharp "Unibit" works great for enlarging holes accurately. Never tried it on wood, but it'll do a beautiful job on soft metals. Unibits work more like a reamer than a drill bit.
Even with a drill press & a good Forstner bit, I've never had much luck enlarging holes. The bits tend to wander on entry if they don't have support for the centre pin of the bit.

I have a ply template of my peghead that I use to rout my peghead contour. It also has press fit drill bushings in place for 10mm holes. If I am putting on Waverly's I change out the 10mm drill bushings for 11/32 Drill bushings that has the same OD as the 10mm bushing (1/2") These shoulder type drill bushings are available at most machine shop supply houses or through McMaster-Carr.

This allows me to just place the peghead flat on a piece of scrap sacrificial ply, on my drill press and drill my holes.

By the way, my templates that hold these bushing are secured in place with golf club grip double sided tape. A lot of holding power but very easy to get off with just a tad bit of heat from a hot air gun or a bit of naphtha. I like it better than carpet tape. It basically will not slip

Even with a drill press & a good Forstner bit, I've never had much luck enlarging holes

Lose the forstners and brad point bits, and use a plain 'ol twist drill. St the speed to the fastest setting, and drill you some nicely lined up holes...

Mike, I like your method. Works like a charm. While you have the hole spacing jig already, if you ever need one of a different spacing, use a similar technique to what you just did for enlarging. Drill two holes, spaced as yo need. test fit them to the tuners or whatever, until you have them perfect. Now, lightly clamp this to the drill press table, and lower the bit(not running!!!) into one of the holes, and let the piece line itself up. Now, clamp tightly. Test to see that the bit is perfectly centered in that hole. This is now your jig! In use, you'll drill the first hole in the series by lining it up to a punch mark of whatever, then, with a pin inserted in the second hole in the jig, you'll set the first drilled hole into that pin, and drill the next one. Repeat until done. Thats it! Oh, you want a fence of some sort to keep the holes aligned, also, but that's a given...

Practice in scrap and test fit the tuners before committing to good wood.

You have to drill the small diameter holes from the back of the peg head because, on some mandolins, the headstock is tapered. If you drill them from the top, the holes will not be perpendicular to the tuner plate. My mandolins don't have tapered heads so it is not as critical for me. I drill the small holes from the back, anyway because I use a hand plane to clean up the head and it would be pretty easy to put a slight taper in without noticing.

Ooh, Mike, careful...

With a tapered headstock, or any headstock for that matter, we really MUST drill from the front, not the back. We want the holes perpendicular to the rear of the headstock(where the tuner's plate will bear), so, the rear of the headstock is the one that must rest on the table(with a backer of scrap, of course).

Hey Mike, any chance you could snap a couple of pics of this jig. I'm having troubles getting my little brain wrapped around your idea. I've got a commission coming up that requires Waverly's and I have never installed them before. Thanks in advance. Paul

Paul, think of a pin router setup...

For Waverly installs, the tool that SM sells is worth twice more than they ask. It's so sweet and cuts so well, I don't even cut the holes until the headstock is finished and buffed!

[QUOTE=grumpy] For Waverly installs, the tool that SM sells is worth twice more than they ask. It's so sweet and cuts so well, I don't even cut the holes until the headstock is finished and buffed![/QUOTE]

Mario, do you use the SM tool in the drill press or just use a hand drill to drill for the bushings? Getting ready to do one and I've never used the tool before.

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Dave Rector
Rector Guitars

Drill press! Goes without saying, I would think.

[QUOTE=grumpy] Ooh, Mike, careful...With a tapered headstock, or any headstock for that matter, we really MUST drill from the front, not the back. We want the holes perpendicular to the rear of the headstock(where the tuner's plate will bear), so, the rear of the headstock is the one that must rest on the table(with a backer of scrap, of course).
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Ah, okay. I wasn't aware of what the drill jig was like, and I now assume you use a hand drill and not a drill press for this operation...

As long as you're indexing off the rear of the headstock is what counts.

OK here are some pics.

First drill the 1/4" hole.


Second, Place the 1/4" pin in the hole and replace the drill bit. Remember, don't move the block.


Then place the headstock on the pin and drill the bushing hole.

[QUOTE=grumpy] Ah, okay. I wasn't aware of what the drill jig was like, and I now assume you use a hand drill and not a drill press for this operation... As long as you're indexing off the rear of the headstock is what counts. <div style=": ; width: 28px; height: 28px; : 1000; display: none;">

 There is a different way to get a stepped hole .Check with your local saw and drill sharpening service to see if a step can be ground into a stock size bit.Name your size and depth of cut .One hole, one pass.

What could be more simple?

Mario thanks for the explanation. Mike thanks for the pics. My little brain knows what you are talking about now. Thanks again, Paul

I use a short length of a wooden dowel for the pin to prevent any possibility of the bit being damaged if it hits the pin.

Mike are you using a Shop Smith?

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Say what you do, Do what you say.

[QUOTE=Dave Rickard] Mike are you using a Shop Smith?[/QUOTE]
Yep. I got it around 1988 or so. I no longer use the table saw function but the drill press and disk sander functions are used all the time. I also use the horizontal boring function. It is great for drilling the holes for bolt on necks.

[QUOTE=grumpy] Drill press! Goes without saying, I would think.[/QUOTE]

Thanks Mario. Guess I was having one of those "DUH" moments. Drilled them this morning and they came out great, on the drill press of course.

_________________
Dave Rector
Rector Guitars