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Machine Shop Practice: Making Custom Metal Hardware For Basses
- Thread starter Bruce Johnson
- Start date
Those of us who played "Magic: The Gathering" also remember a card named "Hunted Wumpus", an homage to that game.
Rôckhewer
Commercial User
- Feb 28, 2015
- 2,922
- 9,028
- Disclosures
- Owner/Builder- RockHewer Custom Guitars LLC
Thanks Bruce.
This one was probably my favorite. It was a lot of fun to make unique hardware.
I think I used an angle grinder & abrasive wheel to cut this brass control plate & tailpiece.
...which is totally the wrong tool for cuttin brass
But it's what I had handy.
Then I went to town with a ball-peen hammer.
I called Hipshot and asked them to send me a D bridge "raw" (no electroplating)... as this hardware was specified to have an aged patina.
This was accomplished by electrolysis.
I threw it all in a water bath with a couple tablespoons of copper sulfate.
And the two leads of an old 12V battery charger.
Takes about 10 minutes.
Thanks Bruce.
This one was probably my favorite. It was a lot of fun to make unique hardware.
I think I used an angle grinder & abrasive wheel to cut this brass control plate & tailpiece.
...which is totally the wrong tool for cuttin brass
But it's what I had handy.
Then I went to town with a ball-peen hammer.
I called Hipshot and asked them to send me a D bridge "raw" (no electroplating)... as this hardware was specified to have an aged patina.
This was accomplished by electrolysis.
I threw it all in a water bath with a couple tablespoons of copper sulfate.
And the two leads of an old 12V battery charger.
Takes about 10 minutes.
View attachment 5078952View attachment 5078954
Those are some really cool ideas for putting a unique finish on metal parts! I've never played around with doing a hammered metal finish. I've hammer-formed aluminum parts and ended up with some of that finish unintentionally.....It's really interesting to do the whole surface of a brass plate like that.
Nice work. And it makes a beautiful accent feature on that particular bass.
When I make shaped brass block parts, I usually bandsaw the shape pretty close to the 2-D plan shape. Then fasten the brass shape to a chunk of maple, using screws through its attachment holes. Clamp the maple in a solid vise and go at it with a couple of 12" or so Bastard files. Big coarse files are the fastest way to 3-D shape a brass block. Shaping brass on a big belt sander is annoying. The part gets real hot and the belt clogs up. A big sharp file takes the chips off peacefully. Get the shape close, then switch to Smooth files, then #2 and #4 Swiss files. Finally, sanding on soft rubber blocks to either a satin finish with Scotchbrite, or buffing it up to a high shine.
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Getting back to the DeTemple aluminum bridges, the first metal hardware project that I'm going through here:
Squaring Up The Blocks
I had previously sawn off the slugs of aluminum bar stock in the cutoff bandsaw, leaving them about 1/16" over length. And I'd quickly deburred the sawn ends. The next step is to trim both ends of the slug to be square and smooth, and bring the length of the block to a specified dimension.
This length will be the final width of the part, so I want to bring the block to about +0.005" of the dimension. Making a batch of parts, I want to make all the blocks the same length, in that +0.005"/-0.000 range.
It's pretty obvious that the best tool for this job is a milling machine. That's their job: cutting flat surfaces parallel and perpendicular to each other. The usual way to square off a block is to clamp it in the mill's vise, hanging off one side. Then use the side of an end mill to make passes over the end of the block.
Like this: Here's where those parallels and the stop come in. The block is resting on the parallels, and is seated against the stop on the right end. That holds all the blocks in an accurate repeatable position. I set the stop so the block is hanging maybe 1/4" out of the side of the vise.
I usually do this operation on the left side of the vise, as shown here. The cut is made using the Y-axis of the mill. As I turn the Y-axis crank, the table, vise and part move straight back in relation to the spinning cutter. The cutter is effectively moving forward on the part, cutting in the Normal Cut (as opposed to Climb Cut) direction. The X-axis (side-to-side) sets the depth of cut.
I have a 1/2" dia x 1 1/2" long 2-flute End Mill in the spindle. I'll be cutting with the side of it, dry, no cutting oil.
The usual sequence of operation is:
For reference, it took me about an hour to do this whole operation on a batch of 11 blocks.
This is the process for squaring the blocks with a milling machine. And you should be thinking about getting one...
In the next post, I'll go through the process for squaring the blocks, if you don't have a milling machine. Yet.
Squaring Up The Blocks
I had previously sawn off the slugs of aluminum bar stock in the cutoff bandsaw, leaving them about 1/16" over length. And I'd quickly deburred the sawn ends. The next step is to trim both ends of the slug to be square and smooth, and bring the length of the block to a specified dimension.
This length will be the final width of the part, so I want to bring the block to about +0.005" of the dimension. Making a batch of parts, I want to make all the blocks the same length, in that +0.005"/-0.000 range.
It's pretty obvious that the best tool for this job is a milling machine. That's their job: cutting flat surfaces parallel and perpendicular to each other. The usual way to square off a block is to clamp it in the mill's vise, hanging off one side. Then use the side of an end mill to make passes over the end of the block.
Like this: Here's where those parallels and the stop come in. The block is resting on the parallels, and is seated against the stop on the right end. That holds all the blocks in an accurate repeatable position. I set the stop so the block is hanging maybe 1/4" out of the side of the vise.
I usually do this operation on the left side of the vise, as shown here. The cut is made using the Y-axis of the mill. As I turn the Y-axis crank, the table, vise and part move straight back in relation to the spinning cutter. The cutter is effectively moving forward on the part, cutting in the Normal Cut (as opposed to Climb Cut) direction. The X-axis (side-to-side) sets the depth of cut.
I have a 1/2" dia x 1 1/2" long 2-flute End Mill in the spindle. I'll be cutting with the side of it, dry, no cutting oil.
The usual sequence of operation is:
Square off one end of all of the blocks first.
Set up: I stand the blocks up on end, all in a row. Compare their height (length). Pick the shortest one. Set that one in the vise, on the parallels and against the stop. With the motor shut off, adjust the X, Y, and Z axes to bring the full side of the end mill touching against the middle of the end face of the block. Lock the X-axis and Zero it on the digital readout (or Zero the leadscrew dial, if you are old school). Back up the Y-axis to move the cutter straight back along side the rear jaw of the vise. That's the "Park" position, where I can leave it spinning, back away from my fingers as I change blocks in the vise.
Test cut: Turn the X-axis to bring the end mill over to the right about 0.010". This will be an initial cut to see if that's enough to square up and clean up the end of the block. Start the spindle, advance the cutter forward with the Y-axis to start cutting the block. Make the full pass, hand feeding the Y-axis until the cutter is off the end of the block. With the spindle still spinning, back it all the way back to the Park position.
Take a look at the end surface that you just cut. You can even take the block out of the vise if you like. Is the whole surface completely cut? Are all the saw marks gone? Was that 0.010" pass enough to make it square and smooth? It depends on how far off-square your sawing was. If it isn't quite cleaned up, put it back in the vise, the same way, and move the X-axis another 0.010". Make another pass. Check it again.
When that first end of the first block looks good, lock the X-axis and reset the readout to Zero. You've now squared one end of the shortest block. Do a quick check on the length of the block. It should still be oversize by around 0.040"-0.050". That's assuming that you sawed the blocks about 1/16" (0.062") over length. That extra length that you still have is what will be taken off the other end, to square it up. But not yet. This is just a check to make sure you have enough material left. All the other blocks will be longer.
Cut one end of all the blocks: Keeping the X-axis locked at Zero, mill the one end of all of the other blocks. Set them all in the vise, seated against the stop, one pass down and back, change to the next block.
Deburr the freshly cut end of all the blocks: Over to the Finishing Wheel. Quickly clean the burrs off of all four edges of the fresh-cut end of each block. Don't skip this step. Those burrs can keep the block from seating correctly in the vise when you cut the other end. If you don't have a Finishing Wheel, a quick swipe with a fine flat file will do it.
Set up for cutting the other end: Pick any one of the blocks. Clamp it in the vise with the squared end against the stop. Advance the X-axis another 0.010" and lock it. Fire it up and make a pass. Check it. Did that square it up? Zero the X-axis at that position. Take the block out and measure it carefully with calipers. It should be maybe 0.030" oversize? If that's the number, then advance the X-axis that far, 0.030". Lock it and Zero it. Put the block back in, seating it carefully against the stop, make a single pass down and back.
Take the block out, measure it. It should now be right to the exact size +0.000", and square on both ends.
Mill the second end of all the rest of the blocks. X-axis at the same setting, first end against the stop, rough end out. One pass down and back, change blocks.
Deburr the second ends of all the blocks. Don't forget.
That's the procedure. The blocks are all squared on both ends, and to an accurate length. A good basis for all the other operations.Set up: I stand the blocks up on end, all in a row. Compare their height (length). Pick the shortest one. Set that one in the vise, on the parallels and against the stop. With the motor shut off, adjust the X, Y, and Z axes to bring the full side of the end mill touching against the middle of the end face of the block. Lock the X-axis and Zero it on the digital readout (or Zero the leadscrew dial, if you are old school). Back up the Y-axis to move the cutter straight back along side the rear jaw of the vise. That's the "Park" position, where I can leave it spinning, back away from my fingers as I change blocks in the vise.
Test cut: Turn the X-axis to bring the end mill over to the right about 0.010". This will be an initial cut to see if that's enough to square up and clean up the end of the block. Start the spindle, advance the cutter forward with the Y-axis to start cutting the block. Make the full pass, hand feeding the Y-axis until the cutter is off the end of the block. With the spindle still spinning, back it all the way back to the Park position.
Take a look at the end surface that you just cut. You can even take the block out of the vise if you like. Is the whole surface completely cut? Are all the saw marks gone? Was that 0.010" pass enough to make it square and smooth? It depends on how far off-square your sawing was. If it isn't quite cleaned up, put it back in the vise, the same way, and move the X-axis another 0.010". Make another pass. Check it again.
When that first end of the first block looks good, lock the X-axis and reset the readout to Zero. You've now squared one end of the shortest block. Do a quick check on the length of the block. It should still be oversize by around 0.040"-0.050". That's assuming that you sawed the blocks about 1/16" (0.062") over length. That extra length that you still have is what will be taken off the other end, to square it up. But not yet. This is just a check to make sure you have enough material left. All the other blocks will be longer.
Cut one end of all the blocks: Keeping the X-axis locked at Zero, mill the one end of all of the other blocks. Set them all in the vise, seated against the stop, one pass down and back, change to the next block.
Deburr the freshly cut end of all the blocks: Over to the Finishing Wheel. Quickly clean the burrs off of all four edges of the fresh-cut end of each block. Don't skip this step. Those burrs can keep the block from seating correctly in the vise when you cut the other end. If you don't have a Finishing Wheel, a quick swipe with a fine flat file will do it.
Set up for cutting the other end: Pick any one of the blocks. Clamp it in the vise with the squared end against the stop. Advance the X-axis another 0.010" and lock it. Fire it up and make a pass. Check it. Did that square it up? Zero the X-axis at that position. Take the block out and measure it carefully with calipers. It should be maybe 0.030" oversize? If that's the number, then advance the X-axis that far, 0.030". Lock it and Zero it. Put the block back in, seating it carefully against the stop, make a single pass down and back.
Take the block out, measure it. It should now be right to the exact size +0.000", and square on both ends.
Mill the second end of all the rest of the blocks. X-axis at the same setting, first end against the stop, rough end out. One pass down and back, change blocks.
Deburr the second ends of all the blocks. Don't forget.
For reference, it took me about an hour to do this whole operation on a batch of 11 blocks.
This is the process for squaring the blocks with a milling machine. And you should be thinking about getting one...
In the next post, I'll go through the process for squaring the blocks, if you don't have a milling machine. Yet.
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Not to be a pest, but I don't think the above was covered. If it was, sorry for missing it. I've been waiting for the Machine Drilling part as without a center punch, my bits wander even though I am using a (cheap) drill press. Thanks!
Yes, that's coming up next: Drilling technique, including Spot Drilling and Machine Drilling. I'm trying to organize this thread along the process I used making the DeTemple bridges.
I'm thinking a duo... Catty Wompus and Miss Alignment
Hah! Or maybe Miss Aline and the Catty Wompus Trio.
On a bad day it's O'Hell and the Bloody Stumps
Back to some more Metalworking Technique, to reduce Catty-Wompus conditions:
Squaring off metal blocks the old-school way......If you don't (yet) have a milling machine. This is done with files, a small square, a scriber, and a good strong smooth-jawed vise.
Some quick notes about files. Files are available in different lengths (sizes), generally ranging from 4" to 14". The length does not include the tang or the handle. They are available in many different shapes, the shape in cross-section. Most common are Flat ( a wide thin rectangle), Half-Round, Square, Triangle (aka Three-Square) and Round. And there are many other special shapes.
Files are also available in different Grades, which is how coarse the teeth are. The tooth grades are proportional to the length; a 12" Bastard file is much coarser than a 6" Bastard file. There are two series of file grades, American Series and Swiss Pattern Series.
American Series files, coarsest to finest, are:
Here are the three files that I use most commonly for basic squaring up of metal blocks:
At the bottom is a 14" Flat Bastard. It peels off the metal very quickly. In the middle is a 10" Flat Smooth. It removes the grooves from the big file. At the top is a 6" Flat Smooth, for cleaning up edges and corners.
Squaring up an aluminum block using files:
Here's an aluminum block that I just grabbed from my scrap bin. It's sawn-off 6061 bar stock, as would be commonly used for making bass hardware. You can see the saw marks on the end. It's approximately cut square, but not square enough.
The first step is to square off one end of the block. Clamp it in your sturdy vise and go at it with the big Flat Bastard file. Notice how I have it clamped; standing up above the jaws, with the end face horizontal. Hold the file horizontally, with two hands (I'm taking the picture here), about elbow height. Push down and forward with some muscle. It will peel metal off faster than you think.
In about 4 long strokes, the saw marks are gone. The end surface is fairly smooth and looking about right.
Here's where the little square comes in. Use it to check the squareness of the end of the block. Notice how the block having the block raised up in the vise makes it real easy to set the square on there and take a look. Filing a metal to precision is all about continuously checking against a reference, a square or a ruler. Make it easy to do the checking.
Take a few more strokes with the big file, pressing more on the end that is high. Check it again with the square. And again, until it's right. You'll get a feel for holding the file horizontal and applying the cutting to the area that is high.
And check for squareness sideways too. Here, you can see that it's a tiny bit off. The left side needs to come down a few thousandths. That's roughly a 0.005" gap you are seeing at the right side. With practice, you'll get a feel for how many file strokes that is to bring it square. Working carefully, you can trim a metal block 0.001" with a file.
Next, the 10" Flat Smooth file takes out the deep scratches of the big file. Check it again with the square, both directions. Light strokes, keeping the file horizontal, applying the cutting evenly over the surface to keep it square. Just enough strokes to take out the deep scratches.
I'll usually leave blocks at a Smooth level of finish during all the other operations. That is, there's no point in making it any shinier right now, because it will probably get a few marks from vises in the other operations. After it's all machined and shaped, I'll go finer than that and take it up to a polish.
The small 4" Flat Smooth file is used to clean off the four edges of the end surface. Remove the burrs, make a tiny bevel. You need to constantly do this when metalworking. Sharp edges can cut you and can interfere with the precision of the next operations. Partly because of the bandages on your fingers.
Use a machinist's ruler and a scriber to make a small scratch at the desired length....Measuring from the end that you just finished squaring up.
Put your little square at the scribed line, and scribe a line all the way across.
And there's the scribed line to use as a guideline. That shows you how long the block needs to be. Watch it carefully.
Now, stand it back up vertically in the vise and go at it with the big Flat Bastard file. Bring it down real close to the line, watching carefully. A sharp 14" file will take off that much in about ten strong strokes. It doesn't take as long as you might imagine. But the part has to be held in a strong vise, and you have to push the file with both hands, shoulders and back. It takes horsepower to peel metal.
Bring it down close to the line with the big Bastard file, checking with the square in both directions. Then switch to the Smooth file to remove the big teeth marks and bring it right to the line. Clean up the edges with the small Smooth file.
With a little practice and patience, you can hand file a block to be square on both ends and accurate in length to 0.002". In machine shop school, one of the early lessons was to have us hand file a steel block to +0.001"/-0.000" tolerance. To get a feel for it. It isn't that hard.
The sequence of the procedure is the same as when using a milling machine:
Squaring off metal blocks the old-school way......If you don't (yet) have a milling machine. This is done with files, a small square, a scriber, and a good strong smooth-jawed vise.
Some quick notes about files. Files are available in different lengths (sizes), generally ranging from 4" to 14". The length does not include the tang or the handle. They are available in many different shapes, the shape in cross-section. Most common are Flat ( a wide thin rectangle), Half-Round, Square, Triangle (aka Three-Square) and Round. And there are many other special shapes.
Files are also available in different Grades, which is how coarse the teeth are. The tooth grades are proportional to the length; a 12" Bastard file is much coarser than a 6" Bastard file. There are two series of file grades, American Series and Swiss Pattern Series.
American Series files, coarsest to finest, are:
- Coarse (rarely seen these days)
- Bastard
- Second (aka 2nd)
- Smooth
- Extra Smooth (rarely seen)
Here are the three files that I use most commonly for basic squaring up of metal blocks:
At the bottom is a 14" Flat Bastard. It peels off the metal very quickly. In the middle is a 10" Flat Smooth. It removes the grooves from the big file. At the top is a 6" Flat Smooth, for cleaning up edges and corners.
Squaring up an aluminum block using files:
Here's an aluminum block that I just grabbed from my scrap bin. It's sawn-off 6061 bar stock, as would be commonly used for making bass hardware. You can see the saw marks on the end. It's approximately cut square, but not square enough.
The first step is to square off one end of the block. Clamp it in your sturdy vise and go at it with the big Flat Bastard file. Notice how I have it clamped; standing up above the jaws, with the end face horizontal. Hold the file horizontally, with two hands (I'm taking the picture here), about elbow height. Push down and forward with some muscle. It will peel metal off faster than you think.
In about 4 long strokes, the saw marks are gone. The end surface is fairly smooth and looking about right.
Here's where the little square comes in. Use it to check the squareness of the end of the block. Notice how the block having the block raised up in the vise makes it real easy to set the square on there and take a look. Filing a metal to precision is all about continuously checking against a reference, a square or a ruler. Make it easy to do the checking.
Take a few more strokes with the big file, pressing more on the end that is high. Check it again with the square. And again, until it's right. You'll get a feel for holding the file horizontal and applying the cutting to the area that is high.
And check for squareness sideways too. Here, you can see that it's a tiny bit off. The left side needs to come down a few thousandths. That's roughly a 0.005" gap you are seeing at the right side. With practice, you'll get a feel for how many file strokes that is to bring it square. Working carefully, you can trim a metal block 0.001" with a file.
Next, the 10" Flat Smooth file takes out the deep scratches of the big file. Check it again with the square, both directions. Light strokes, keeping the file horizontal, applying the cutting evenly over the surface to keep it square. Just enough strokes to take out the deep scratches.
I'll usually leave blocks at a Smooth level of finish during all the other operations. That is, there's no point in making it any shinier right now, because it will probably get a few marks from vises in the other operations. After it's all machined and shaped, I'll go finer than that and take it up to a polish.
The small 4" Flat Smooth file is used to clean off the four edges of the end surface. Remove the burrs, make a tiny bevel. You need to constantly do this when metalworking. Sharp edges can cut you and can interfere with the precision of the next operations. Partly because of the bandages on your fingers.
Use a machinist's ruler and a scriber to make a small scratch at the desired length....Measuring from the end that you just finished squaring up.
Put your little square at the scribed line, and scribe a line all the way across.
And there's the scribed line to use as a guideline. That shows you how long the block needs to be. Watch it carefully.
Now, stand it back up vertically in the vise and go at it with the big Flat Bastard file. Bring it down real close to the line, watching carefully. A sharp 14" file will take off that much in about ten strong strokes. It doesn't take as long as you might imagine. But the part has to be held in a strong vise, and you have to push the file with both hands, shoulders and back. It takes horsepower to peel metal.
Bring it down close to the line with the big Bastard file, checking with the square in both directions. Then switch to the Smooth file to remove the big teeth marks and bring it right to the line. Clean up the edges with the small Smooth file.
With a little practice and patience, you can hand file a block to be square on both ends and accurate in length to 0.002". In machine shop school, one of the early lessons was to have us hand file a steel block to +0.001"/-0.000" tolerance. To get a feel for it. It isn't that hard.
The sequence of the procedure is the same as when using a milling machine:
- Saw the block off maybe 1/16" over length
- File one end square and smooth
- Measure from that end, marking a line for the finished length
- File the other end square and smooth, bringing it right to that line. Not past it.
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A note to remind myself when I circle back to this:
Buy some new files only for metalworking... Except when working on metal flake tonewood.
Buy some new files only for metalworking... Except when working on metal flake tonewood.
Takes me back 65 years Bruce. Yes, 65! That's when I started a 5-year apprenticeship in mechanical engineering with 6 months in the firm's apprentice training school. I remember the instructor who taught us saying "use the biggest file (not the coarsest) you comfortably can. It's much easier to file flat and square with a big file than with a small one". Do you agree? In those 6 months we made some of our own tools, centre punch, scriber, scribing block, rule stand, etc. and a sheet metal tool box to put them in. Those days are gone.
Seems like the kind of job for fully anchored vise and not clamp-on if I'm not mistaken...
If this is the case, can those of us starting out plan on a single vise with ability to swap for smooth/rabbited/stepped inserts? Something in the 5" opening and 4" jaw width or would that be overkill? Would it be better to stick with non-swivel bases (though these seem super common) and just mount it somewhere you can hit it from most sides?
I am amazed at how many options they have for something as simple as a vise.
If this is the case, can those of us starting out plan on a single vise with ability to swap for smooth/rabbited/stepped inserts? Something in the 5" opening and 4" jaw width or would that be overkill? Would it be better to stick with non-swivel bases (though these seem super common) and just mount it somewhere you can hit it from most sides?
I am amazed at how many options they have for something as simple as a vise.
Bruce, your Little Square has a feature that to me looks a bit like an adjustment wheel. Is it in some way adjustable?
Edit: photo added.
Edit: photo added.
I *think* that moves the ruler for precise measurements.
Yes, absolutely! You should keep some files only for woodworking use, and others only for metalworking. I even separate them somewhat on the metalworking bench; some only for aluminum and brass, others only for steel and stainless.
Get new, sharp files for your woodworking. When those files start to get a little dull, get new ones and reassign the old ones to be your aluminum files. And reassign your current aluminum files to steel.
