Handmade bass bridges/tailpieces, info and build thread

[William Shafer]

Good afternoon Forum,

It's been a few months on TalkBass for me and I've already learned a lot. What has inspired me greatly are the few luthiers who have done various degrees of metal work. Now, I'm not in a position to do steel working at the moment, but I've seen quite a bit about brass. I did some digging online and discovered that I should be able to work brass with some of my wood working gear. When the time comes for my third build I want to do a floating bridge and a laminate brass/cocobolo tail piece a la Alembic (in my own shape).

Bruce has a metal shop and does some excellent work. What are the experiences of the forum when it comes to brass? I understand it'll be softer then steel of course but harder then aluminum right? Also, I remember back from my welding/brazing days brass melts under the heat of propane so after I get my feet wet with basic machining of brass I may attempt casting full brass tail pieces. The reason I ask is a combination of wanting to do metal work again and frankly building good looking instrument while saving some money on bridges.

Thanks and have a great evening!

 

[reverendrally]

I think there is a thread about hand made bridges or similar. Maybe do a search. It was reasonably recent I think.

 

[Bruce Johnson]

That was my thread about building the replica Performer bridge. I'm planning to do a series of threads here on Luthiers Corner called Metalwork: (something), showing the processes that I use to make various instrument hardware. I've been trying my best to encourage you all to make some of your own metal hardware. It really isn't that hard, and it's a great way to add creative ideas and value to your instruments.

I've been meaning to update that thread about the Performer bridge to explain how you can make parts like those without having a mill and a lathe. Metal parts can indeed be made with a drill press, a vise, a hacksaw, and some files. Even steel parts.

Aluminum and brass are easy to work with, even with hand tools. Aluminum is definitely the easiest metal to machine, although it varies a lot between the different available alloys. I use aluminum for most of the hardware on my basses these days. It's light weight, easy to machine, cheap, and strong enough for most parts. I use brass in a few places, where I specifically want stronger threads or extra weight. I use stainless steel for some parts where I need a lasting polished shine.

Brass is easy to saw and file to shape. The only tricky thing about brass is drilling it. Regular drill bits will dig into brass, and grab and jam easily. You have to be careful. Don't try to enlarge a hole in brass; running a larger size bit down into a smaller size hole. It will grab and lock up. The best way to drill brass is to use a drill bit which has been "drubbed" or cleverly de-sharpened. You take a regular drill bit and make a small perpendicular flat edge on the cutting edges, on the edge of a sharpening stone. That will make the bit drill brass nicely in small chips, without grabbing. I'll post some pictures later of how to do this, for those of you who aren't familiar with it.

Both aluminum and brass can be cut with a normal woodworking-type bandsaw. I have an Enco 14" woodworking bandsaw that I keep dedicated just for cutting aluminum and brass. I keep a standard 1/4" x 10tpi woodcutting blade on it, and it runs at normal woodcutting speed. It has no problem cutting up to 1/2" thick aluminum or brass. Beyond that, it starts bogging down in power. You can use your normal shop bandsaw for cutting brass and aluminum, but I recommend that you keep a separate blade just for that purpose, and clean it well in between. You don't want to get the metal dust embedded in wood workpieces.

One warning: Bandsawing aluminum in particular is VERY LOUD! Wear ear protection and don't do it at 2 am when the family is sleeping. Also, the parts can heat up quickly as you cut. Be careful not to get burned.

DO NOT try to cut steel or stainless on a woodworking bandsaw! The blade speed is about 10 times too fast, literally. You'll instantly destroy the blade, throwing sparks and metal shards. For those metals, you need a bandsaw which is specifically set up for that job with a gear and belt reduction to bring the blade speed down into the right range. And that speed range is way too slow for aluminum and brass. That's why I have one 14" bandsaw set up just for steel and stainless, and one just for aluminum and brass.

I'll add more later. The steam whistle is blowing and I've got to get back to my shop. I'm doing some metal work right now, making up a pair of pickguard-like body plates from 0.040" 7075 aluminum, fitting them to one of the Trussart SteelScrollPeg basses.

 

[William Shafer]

Thank you Bruce! I created this thread to not take over yours about the performer thread. Also, I wanted this thread to be more general discussion about the process rather then about making a specific bridge for a specific bass. I greatly appreciate the tip about drilling holes in brass, I can avoid the binding from the beginning.
As I start this process from the beginning I'll document it as well so everyone can see the steps and when I do some casting I'll post it hear as well.

Any tips, suggestions, or personal experiences are greatly appreciated. Again, I created this thread as a general purpose thread rather then a specific one. Thanks again to Bruce for kicking it off!

 

[Arie X]

Good afternoon Forum,


It's been a few months on TalkBass for me and I've already learned a lot. What has inspired me greatly are the few luthiers who have done various degrees of metal work. Now, I'm not in a position to do steel working at the moment, but I've seen quite a bit about brass. I did some digging online and discovered that I should be able to work brass with some of my wood working gear. When the time comes for my third build I want to do a floating bridge and a laminate brass/cocobolo tail piece a la Alembic (in my own shape).

Bruce has a metal shop and does some excellent work. What are the experiences of the forum when it comes to brass? I understand it'll be softer then steel of course but harder then aluminum right? Also, I remember back from my welding/brazing days brass melts under the heat of propane so after I get my feet wet with basic machining of brass I may attempt casting full brass tail pieces. The reason I ask is a combination of wanting to do metal work again and frankly building good looking instrument while saving some money on bridges.

Thanks and have a great evening!

-basically everything about woodworking cutting tool geometry is unsuitable for metal work.
-i don't think you'll save much money, but you'll learn new stuff and make what you want which is a good thing.

i have nearly 4 decades of industrial metal working exp, from tool/die/mold making and design, to 5 axis CNC programming, etc...and am now a Sr.Mfg. Eng. at a particle accelerator r&d facility. i've cut/formed/molded/heat-treated, etc.. and processed the majority of the metals and plastics out there as well as a fair amount of weird periodic table elements and i can certainly bore almost anybody to death with extreme details

what specific questions do you have?

 

[William Shafer]

Arie X I'm going to have to give that some thought... love to pick your brain though. You're right, I'm probably not going to save much money on off the shelf parts, but I'm trained as an artist and the idea of making my own bridges and tailpieces to my own dimensions and to my own design is what is attractive. Maybe I'll have you bore me with specific of metallurgy on a different thread (I'm actually really into that type of info)

 

[William Shafer]

Preliminary drawings for a laminate brass/wood tailpiece and a wooden bridge.

 

[Arie X]

how would you anchor the ball ends of the strings? small c/bores in the wood portion that is underneath the brass laminate?

 

[William Shafer]

Yes. I'm going to cut and file the channels you see in the top view on the brass prior to lamination then drill from the back maybe 1/4" just deep enough to catch the ball-ends. Like this:

 

[Bruce Johnson]

Sure, that'll work. A good basic design, with the brass plate being functional and decorative.

A couple of suggestions:

To anchor the strings, all you need is a simple straight notch in the brass plate. Drill a 3/16" hole and saw a straight slot to it from the back edge, like you've shown. In the wood block underneath, you'll want a 3/8"wide x 5/16" deep slot to clear the ball end.

I'd recommend 1/8" thick brass plate. Thinner than that might distort under the load. File a 45 degree flat bevel all around the perimeter of the plate. Brass plates look great with a simple beveled edge. Also use stainless steel oval head phillips machine screws to fasten the brass plate down to the wood block (and/or down through into the body). For some reason stainless screws look very elegant in brass plates. I like the look better than brass screws.

For some extra coolness, belt sand a slight side-to-side radius on the top of the wood block, then gently bend the brass plate to fit. It doesn't have to be a lot of radius; even a slight radius will look more elegant than a completely flat plate.

Edit: Hah, those guys at Alembic must have just read my post!

 

[William Shafer]

Think I'll take most of your advice! I already bought the screws though and they have to go into stand offs. (Using Parota and it has a reputation for not holding screws so I got brass stand offs to epoxy/wedge into the body)

 

[Bruce Johnson]

By the way, don't try to do what you think you see on that Alembic tailpiece. Trying to drill those back holes into the brass and wood sandwich would be a disaster. The bit would grab into the brass and kick out, breaking the wood. I doubt that they actually drilled the brass and wood at the same time. If they did, it was done with the sandwich clamped in the vise of a milling machine, and making the holes by plunging down with an end mill. That would work.

For your tailpiece, I'd make the slots in the wood by routing them from the top using a 3/8" cove (round nose) bit. The other option would be to start with the wood block thicker and drill 3/8" holes from the back. Then trim away the top surface of the block until you break through into the tops of the holes.

 

[Rôckhewer]

I am by no means anywhere near the experience level of Bruce or others in working metal.
Fact is, I have no love for it at all. But I do recognise that having my own custom hardware adds some cool factor & originality to my builds.
The first time I made one of my "batwing" tailpieces, I did not have access to any metal specific tools whatsoever.
I drilled the string & mount holes first in a vise on the drill press while it was still in blocky blank form.

Then pretty much just hacked out the shape by drilling relief holes to make hacksawing easier.

Once it was roughly cut out, I sculpted the shape with abrasives...like flap wheels on an angle grinder, & drum sanders on a die grinder.
As a result, this first one has a very organic feel.

Now that I have access to a waterjet, and milling machine... they are coming out a bit more precise & refined...& a little bit faster to create...

But you definitely don't "need" tools like that.
Brass is pretty easy to shape by abrasives.

 

[rudy4444]

I normally build banjos and make all of the hardware (tension band, tone ring, bracket shoes, adjustable tailpiece) from raw brass. I've also done a few bass bridges and string anchor assemblies. It's quite easy to work brass, it sands and polishes easily, and you can use a patina finish which is very attractive if you don't want to have anything plated.

As Bruce says, normal woodworking tools are fine to use. I saw all my brass using the 3 tpi skip tooth bi-metal blade that I use for virtually all my woodworking tasks, too.

 

[Bruce Johnson]

Here's the tailpiece that I make up for my AMB-2 Scroll Basses. This picture shows three of the stages in the process. The tailpiece starts out as some 1/2" thick x 4" wide 6061 aluminum bar stock.

The first step is to saw off the bar stock to the right length, and then I use the milling machine to square off the ends. Then, in the milling machine, I drill the four mounting holes in the top surface.

Then I stand it up and drill the four string holes in from the back edge. For accuracy, everything is referenced from one corner of the block.

On the front face, I drill two starter holes, and then bandsaw out the rectangular notch in the front. Then the rectangular notch gets milled square and straight.

Back in the mill, sitting on a 20 degree angle block, I mill the four string grooves with a rounded ball end mill. This is a fairly tricky operation, trying to get the surface finish inside the grooves as smooth as I can. Each slot gets two deep passes to rough it out, followed by a final light pass with cutting oil in the climb direction.

I use a cardboard template and a Sharpie to mark the outside shape, and bandsaw it out. Then I use two drywall screws to fasten it to a holding block, which is just a shaped chunk of 4 x 4. The holding block makes it easy to do the rest of the operations. I can clamp it in the vise turned different ways or at an angle, as I shape the sides with big files. To speed things up, I do some of the rough shaping on my edge sander, on an 80 grit Zirconia belt that I use only on aluminum. But most of the shaping is done by hand with files, from a 14" Bastard file up to a #2 Swiss.

Once the shape is right with the files, I sand out the file marks with 400 grit paper on a small rubber block, then blend and smooth it with a combi-flap wheel in an electric drill. Tailpieces that get a satin finish get the final surface with a grey Scotchbrite wheel.

Tailpieces going out for nickel plating get hand sanded to 800 grit, then buffed up to a mild shine with black compound on a sewn cotton wheel. Parts going out for plating don't need to perfectly buffed, but all scratches deeper than 1000 grit need to be taken out.

That's about it! I usually make these tailpieces in batches of 4 or 5 at a time, and they take about 1.8 hours each.

Some general notes about a part like this:

Most of you could make a part like this without a milling machine or much of a machine shop. The one exception is those round bottom milled slots; that would be hard to do by hand. But everything else could be done with a drill press, a bandsaw, files, and a good vise. Really. The milling machine just saves me time and makes the parts more consistent.

A key point is to start with a rectangular block of metal, and work from the inside outwards. Lay out and drill all the holes first. Then saw out the perimeter shape. Then mount it to a holding block to do all the contour shaping, smoothing, and polishing.