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I have found my nemesis, and that nemesis appears to be drilling a straight, evenly spaced group of bridge pin holes. #$@#$. Four blanks and several profane outbursts later, I think I have a plan, but before I implement said plan I figure I ought to learn from your experiences. How do you do it? I'm going to pick up a high quality brad point bit, mark using a compass to get perfect spacing, drill slowly so the bit doesn't drift, and make a template out of a ruined blank. I'm getting angry.

Thankfully, the local wood supplier has a pallet full of honduran rosewood castoffs from a local marimba manufacturer. Perfect size for bridges, headplates and such. 2 bucks a pound....that helps ease the financial hit.

Accurate marking, a 3/16" brad point bit, and a drill press. I also wear magnifiers so I can verify that the brad point is hitting exactly at the intersection of my marks.

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Steve Smith
"Music is what feelings sound like"

Do a search for Tony Karol's jig system for the saddle slot and pin holes. I've used it for 5 or 6 years and it works great.

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Try marking the hole location with a center punch. Or even tap a small nail to mark the spot. That should eliminate the drill bit slipping off the mark. You can even "feel" when the drill bit gets into the punch mark

Thanks for the tips. I have a spanking new brad point bit that should find the fine punch marks easily, will use it to make an accurate template. Never would have thunk this'd be that much of a hassle....

I get a lot of mileage out of the stew Mac ruler for the spacing...

This isn't a solution, but it is an alternative. Don't use a straight line.
If it's supposed to be straight and evenly spaced, even very minor imperfections are easily visible. With a curve, the imperfections are not nearly as obvious.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

I was a machinist in a former life so I have made a drilling jig out of 1/4" AL plate. It does not get used enough to worry about wear so that is why AL was used. It clamps to my bridge and away we go. Certainly nothing fancy but quick and accurate.
Tom

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A person who has never made a mistake has never made anything!!!

The LMI jig http://www.lmii.com/CartTwo/thirdproducts.asp?CategoryName=Specialty+Tools&NameProdHeader=Bridge+Drill+Jig is a little expensive but works real well. Several different pin spacings included.

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

Fence on a drill press to keep the holes in line.

Mark holes with a punch.

Kevin Looker

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I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

Just another thing, if you put them in a straight line make them parallel to the saddle slot. Your break angle will be even across the strings and they will not be parallel to the grain to minimize a split in the bridge. It's also easier to install a K&K pickup in a guitar with unslotted bridge pins as the center of the saddle slot will not be right on top of the slot in the low E hole.

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It's not what you don't know that hurts you, it's what you do know that's wrong.

In my experience, it depends on the orientation of the grain you're drilling. On stock that is vertical grain or nearly so, if your layout line lands on a grain line between harder and softer wood, your punch will favor the softer wood. (This assumes a rounded or pointed punch. Flat bottomed punches, unless extremely narrow, would not guide the center spur nearly so well.) Once your punch wanders, your drill bit will not be far behind. On flat, face grain stock, this is not nearly so great a problem. Punch it accurately and the drill bit will usually follow accurately. I realize this brings ups the subject of grain orientation on bridge stock, and I have probably just kicked a hornet's nest. I am writing for the benefit of those lurkers who have not yet drilled into a center-punched piece of vertical grain hardwood--regardless of where that piece of wood might be located on an instrument or other project. It can, indeed, be tricky. I think a well-made drilling template/guide, fashioned from a material without grain and used with a brad point bit would be the ultimate answer to accurately repeatable results.

I've used a punch but honestly don't find it necessary as long as I have a sharp brad point bit. It's almost impossible to drill well-aligned holes with a standard drill bit in wood that has any kind of grain to it. I've had bits bend to follow into the softwood - I'm sure most of you have seen this too.

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Steve Smith
"Music is what feelings sound like"

For perfect spacing, a proportional divider works quickly and accurately. Got the idea from Frank Ford.

Lots of good info here already.

But if I may add, try to make your drill bit turn as fast as possible. As it was mentioned before, the wood grain can 'catch' the drill bit and push it away from the pilot punch hole. A fast spinning bit will reduce that possibility. No matter how clever your method or jig can be, a 3/8'' bit is flexible enough for a tough wood (such as most bridge wood) to mess around with it. (Although I have to admit the LMI jig looks quite effecient, albeit expensive indeed...)

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

I use a Karol-inspired jig just like Terry shows, but only for the saddle slot. I used the little spacer block to make a few different drill guiding jigs, which held up OK for a while, but I finally got tired of messing with them and bought the LMI jig. Drilling holes in bridge blanks is not something I'm interested in spending a lot of time and effort on, especially if the result has the potential of ending up so-so.

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Rian Gitar og Mandolin

Tom: I mentioned that I had worked as a machinist. Drilling 6 equally spaced holes in a straight line in metal is a no brainer. When I first started to build guitars I had vertually no wood working experience and approached drilling holes accurately in wood thinking it would be just as easy as drilling holes in metal. What a wake up....! Inconsistancy popped up quite often.
Drilling the holes without a jig opens up a few areas where one can creat problems.
1. First one has to lay out the holes accurately. Equally spaced with a given total width.
2. One has to center punch the holes on the lay out marks. In wood the punch wants to follow the grain lines as others have pointed out.
3. One then has to start the drill hoping the drill does not cut more in a soft grain line than in a hard grain line. This will happen...........!
I tried to improve my skill to be able to do it this way but could not. I applaud any one that can do this accurately.
Finally a simple metal jig that one clamps to the wood and very quickly the job is done. Repeatable accuracy.
I also have jigs for the head plate and side markers in the finger board. This from a person who uses as few jigs as possible.
Terence Kennedys jig looks very good in that it controls the hole locations in two plains but to me may still not prevent the drill from being pulled off centre. Maybe he could speak to that.
Enough of my rant for today. My main point was to try to help new comers to not get caught up in frustration doing an operation that at first glance looks very easy.
Tom

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A person who has never made a mistake has never made anything!!!

They have been quite accurate with the Karol jig. I use a brad tipped bit on the drill press and kind of ease it in. Probably not up to aerospace or biomedical standards but very acceptable.

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Much thanks for all of the educational replies. I don't feel quite as foolish as I did a few days ago. Here's the solution I came up with - first, I marked the holes using the sharp ends of an inside micrometer set at .450. Saw this on youtube, and it worked perfectly. Then I tried it withouth a jig, using the press. Press the brad into the mark, turn on the press. Worked pretty well - that ended up being the bridge I will use, will compensate one hole about 1/32 by adjusting the slot in the pin hole.

Now the fun part. WHile I was on a roll, I pulled out a scrap piece of engineered Santos Mahogany flooring - pretty hard stuff and very stable since it's laminated, I've used it for other jigs - and routed a saddle slot all the way through. Then I drilled the pin holes, using what I learned from the bridge I just finished. Holes came out perfect. After that, I glued a piece of 1/8 scrap into the saddle slot. So next time, I drop my new template into a newly routed saddle slot, line up the centerlines, and drill away. Should be perfect, repeatable, and take all of five minutes. Will make a few more bridges tonight to test it out. Wish a had access to a CNC or a machine shop, a jig like this made out of aluminum would be very slick.

Thanks again. This stuff is one of my favorite parts of my new hobby.

Tom, thanks for your rant! I've struggled using the non-jigged methods. I have some 1/4" aluminum around here, sans grain lines, and before I make another bridge I'm going to try making a metal jig.

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Tim Allen
"Never hurry, never rest."