tools for cutting and shaping a bridge?

stkowalski · #1 04-02-2008, 01:38 PM

hello everyone, i am by all means not a luthier by any standard but i am seeking to learn some tricks of the trade in minor repair ect. for example, what tools are required or recommended for shaping and cutting a new bridge? another question i have is there any varnish or oil that is used after the bridge has been cut, shaped and filed? any thoughts or recommendations would be great. thank you

1st Bass · #2 04-02-2008, 02:48 PM

It can be done with just a knife and a keen eye, but I use a pencil, a small square, a bandsaw, an oscillating spindle sander, a knife, two scrapers and three files. In about that order. :-)

The principle is that you want the side of the bridge toward the tailpiece to be at right angles to the belly (at that point only;--I realize the belly is curved), the feet should be fitted airtight, centered on the bassbar and the lateral location of the soundpost (the SP is about 20mm south of the treble foot, give or take a few), and holding the strings at the proper height, and spacing.

There is a great deal of printed information available on the subject--start with Chuck Traeger's book, if you want. You will at least find it a fascinating read, even if not everyone agrees with everything he says.

stkowalski · #3 04-02-2008, 05:25 PM

thanks for the information, what size of a blade on the knife? 9mm blade, 12 mm blade ect. or does that depend on the situation? i noticed on internationalviolin.com that there is a craftsman knife set. would that fit (pardon the pun) all my bridge shaping needs? is there a better place to shop for tools? thanks again

jimmyduded · #4 04-02-2008, 05:48 PM

as for tricks, nothing beats working with an actual luthier because they have many little tricks they will never tell anyone they dont trust, knives, woodcraft.com sells some nice ones, howardcore.com also has alot of tools you might be interested in, a bandsaw is a very good investment(check your local craigslist) for various jobs

**Matthew Tucker** · #5 04-02-2008, 08:35 PM

Hey there are lots of threads here on how to do it, so search. But in terms of tools?

1. You need something to chop the excess meat off the bottom and top of the bridge. best=bandsaw. workable=coping saw, at-a-pinch=wood saw (yuk)

2. You need something to shape the feet exactly to the top.
best=sharp knife or scraper. workable=sandpaper ...

3. You need something to thin the blank
Some use a plane. others use a belt sander or rasp. I use a plane.

4. You need something to apply the chamfers
I use a sharp shallow gouge. Most use a knife or file. And some don't even bother with this!

5. You need something to file the nut grooves.
You'll need a few sizes, which you'll use for the nut grooves as well ... note that fine files tend to clog. I've used all manner of things for this job, but the cheapest and best solution I'vs found is to buy some thin files (like a chainsaw sharpening file) and grind off the sides to the width that you want.

6. if you're fitting a bridge wing pickup, you'll need something for shaping the underside of the wing.

As with MOST jobs, you are best served with a variety of tools and choose which one you want depending on the situation. I've a whole bunch of chisels, gouges, files, knives and planes that I've bought, borrowed, found, made or stolen - and I usually start by choosing the sharpest!

stkowalski · #6 04-02-2008, 10:08 PM

thank you all, this has been very informative so far. matthew used a term that i am not familar with "chamfers", what are chamfers? and thanks again

**Matthew Tucker** · #7 04-02-2008, 10:59 PM

Chamfers can make the edges look nicer. A piece of wood with a straight edge is OK but if you cut the edge off at an angle it looks better. If you do it well it looks fantastic, but if you round the edges over it looks like crap. And you have to think before doing this. How do you want the chamfers to begin and end? What happens at the pointy bits? What happens when the chamfer runs into the nibs (do they have a proper name? Ears? Elbows? Knees?) at the top of the legs? Are you going to chamfer the top face AND the bottom face? Are you going to bother at all? You don't have to chamfer the edges ...

**Matthew Tucker** · #8 04-02-2008, 11:11 PM

... oh and some of the other things you have to think about are ...what if the fingerboard is crooked? or if the top is sunken and uneven or damaged at the bridge foot? What size blank do you need? How much are you going to pay for a blank? What side faces up? Are you going to bother cleaning up the edges of the blank? What string spacing do you want? What if you set the string height too low and the thing starts to buzz? Lastly .. do you need a leg-spreader?

I'm not going to explain this last one ... someone else can :*)

It's all fun, but it's not all straightforward.

stkowalski · #9 04-06-2008, 08:36 PM

sorry for the delay....gigs, gigs and more gigs!!!! i just wanted to say thank you to everyone. i hope to be working on a bridge in the next couple of weeks when i have few days off from...you know....gigs.

whats a leg-spreader and don't i need to see some sort of doctor for that? LOL!