They are set up to do ~1/4” fretboards, does anyone make a bolt on mod to use them for ~1” one piece necks?
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Question about Stewmac style fretting mitre box
- Thread starter NathOBX
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- fret slotting fretting
I doubt that anyone makes and sells a mod kit, but many folks have made their own. Basically, just add some spacers of wood or metal to raise the front and back rails up about 3/4". And you may also spread the rails a little farther apart to get clearance for the headstock. Easy fixture work.
I really cannot recommend that tool; $275 is a huge chunk of change for a specialty tool of that purpose. I know that if I measure everything in detail with a micrometer, there is more variation in a handheld sawblade kerf with back & forth motion than a single direction powered blade.
Having made at least 500 fretboards over the decades using almost every commercial system available, the $$$ would be far better off putting into a nice used tablesaw. It will offer infinitely more building possibilities; then get a tablesaw based slotting system for very accurate, easy, fast fretboard slotting of all types. While I paid almost $5k for my fancy Sawstop, it won't work with a fret sawing blade. (Not officially; at one time I was able to hack everything and make it work, but the engineering people at the company got very upset and started yelling at me when I talked to them about it!). I picked up a beautiful mid 1940s Delta Unisaw with all of the art deco goodies and covers for less than $100 a few blocks from my house. I have that one set up for very delicate work using just a fretsaw blade or very thin kerf small blades to make binding and such, almost always less than 3/8" cuts.
Here are the saws back when I had them bolted together for a superstation:
After my big sturdy apprentice left and all of the recent ones seem to by tiny and not very strong, I divorced the two and now the unisaw rides around the shop solo. I recently added a very accurate Incra fence that was basically a garage sale freebee to the top. I do believe that it alone is accurate enough that I could slot a fretboard using just that tool. It would be much better than what I did in the early days. I have less than $275 into the whole setup, including a nice fretting blade and a couple of scale templates.
Bruce: Remember back in the dark ages when we used to cut fingerboards by hand using the Irving Sloan ruler with a bunch of "proper" fret position marks on it? Sometimes the intonation would drive my ears so nuts that I would rip the whole fretted fingerboard off and make a new one....!!!
Having made at least 500 fretboards over the decades using almost every commercial system available, the $$$ would be far better off putting into a nice used tablesaw. It will offer infinitely more building possibilities; then get a tablesaw based slotting system for very accurate, easy, fast fretboard slotting of all types. While I paid almost $5k for my fancy Sawstop, it won't work with a fret sawing blade. (Not officially; at one time I was able to hack everything and make it work, but the engineering people at the company got very upset and started yelling at me when I talked to them about it!). I picked up a beautiful mid 1940s Delta Unisaw with all of the art deco goodies and covers for less than $100 a few blocks from my house. I have that one set up for very delicate work using just a fretsaw blade or very thin kerf small blades to make binding and such, almost always less than 3/8" cuts.
Here are the saws back when I had them bolted together for a superstation:
After my big sturdy apprentice left and all of the recent ones seem to by tiny and not very strong, I divorced the two and now the unisaw rides around the shop solo. I recently added a very accurate Incra fence that was basically a garage sale freebee to the top. I do believe that it alone is accurate enough that I could slot a fretboard using just that tool. It would be much better than what I did in the early days. I have less than $275 into the whole setup, including a nice fretting blade and a couple of scale templates.
Bruce: Remember back in the dark ages when we used to cut fingerboards by hand using the Irving Sloan ruler with a bunch of "proper" fret position marks on it? Sometimes the intonation would drive my ears so nuts that I would rip the whole fretted fingerboard off and make a new one....!!!
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Hey James;
You and I both have enough experience in this business to know that fret slots have to be positioned quite accurately to get good intonation out of our instruments. I did some testing years back and came to the conclusion that frets need to be within +/- 0.005" of their correct position for good intonation on an electric bass. I built my special fret slotting saw (you've seen it) almost 30 years ago (!!!) and I built it very carefully to work within that tolerance. And it has done it reliably. With a little extra patience and care, I've cut slots to +/- 0.002" positional accuracy. Over the years, I've slotted about two thousand necks and fingerboards with it. And I've measured and checked many of them along the way.
I'm sure your tablesaw rig cuts well within that tolerance range.
But...most of the Luthiers here aren't as fussy as you and I are, and aren't willing to make this kind of investment to do one "simple" operation in the build process. I generally recommend that they buy the pre-slotted fingerboards from LMI if they will work for the project. I've bought and used the LMI boards at times, and they are quite good and accurate, well within +/- 0.005".
If they want to cut their own slots, then I recommend using one of the Stew-Mac style miter boxes with the hand saw. Adjusted correctly and used with some care, they can get to +/- 0.005". With care and correct adjustment. Sloppy setup gets sloppy results.
About 15 years ago, a super-fussy Luthier friend of mine challenged me to build him the absolute best guided hand saw fret slotting rig. I took on the challenge and that rig actually works in the +/- 0.002" range. We measured many test pieces and finished necks. It was built to slot full one-piece necks. He's still using that machine. I recently had it back here for a few upgrades. My point is that you can get high accuracy with a guided handsaw fixture rig. If you do the homework.
Now, using a hand saw to cut slots to pencil lines or printed paper lines........Well, that requires some serious skill and patience to get the slots into the +/- 0.005" tolerance range. It can be done, but it's not easy at all. We're getting into that over on the other thread about cutting your own fanned fret slots.......
Unfortunately, there are many Luthiers who think that getting fret slots within +/- 1/16" is good enough. For an electric bass. I have to hold my words and be real careful. I don't want to make them angry or discourage them.
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+/- 1,5mm is for sure not accurate at all, it is just sloppy. I'd say something like +/- 0,2-0,1mm is doable with mitre box or even without one, it just takes patience, caution and good ruler and guide. And of course a lot of light and magnifier for us glass-eyed folks.
So a fret is .080" wide (jumbo), the tang is .020" wide. Your saw starts out at 4x the margin of error (.005") so if your paper lines are .010"-.015" (reasonable given a 600 DPI printer) as long as your saw blade is covering the printed line you should be within the .005" margin of error that Bruce references.
With paper template stretching of the paper while printing and gluing worries me a bit. I don't know if that is a real problem.
It can be. The most common problem with accuracy of printed paper templates is slippage of the paper through the printer's rollers in the long axis. The paper feeds through under the print head by rubber friction rollers, and any slippage means stretched or shrunken dimensions. And the slippage can be little spots at random places. I've run into this with ink jet printers in particular. They can be pretty accurate in the crosswise direction, and have random stretched zones in the lengthwise direction.
One way to reduce this is to print your patterns on heavier weight paper, like 28 lb stock. The rollers will grip the thicker paper tighter. And the heavier paper is less likely to stretch or wrinkle.
I use CAD drawn printed paper templates a lot for full size layouts of shapes, like body perimeters and routed cavity shapes. Most of that isn't very high tolerance. But, I always draw a grid of lines in the background, 1.000" apart. After printing it out, I lay a machinist's ruler on it and check that the grid lines up in both axes.
If you use a CAD-generated paper printout to locate your fretlines, also print out the chart of numbers of the spacing of the frets, to 3 places (0.000"). Then, with the paper template in position on the wood, check the positions of all of the fret lines with a machinist's ruler, against the numbers on the chart. Measure from the Zero line to each fret.
Also, if you are drawing your fret lines in a CAD program, you should set the Line Width right to 0.020". The main steel flat part of the blade of a fret slotting saw is 0.020" thick; only the teeth are kerfed out to 0.023" wide. Set a squaring block on top of the paper, lining up its vertical side exactly with the side of the 0.020" wide printed line, and clamp the squaring block down. Now, if you keep the saw sliding against the block, it will be lined up centered over the printed line. Using this technique carefully, you can get within that +/- 0.005" accuracy range.
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When I've used printed layouts I use wFret, which prints out across the width of the page with alignment marks for using the overlapping sections of the printed layout. I do double check printed layouts with a reliable measurement. I would never trust a layout that prints along the length of a page for the reasons Bruce has explained so well.
I much prefer transferring the fret locations from a printed layout guide directly to the work and then extending the marked line across the board with a precision square. Applied paper is too fussy and messy IMHO. When you produce an accurately printed layout guide it's even better to transfer it to the backside of a cheap aluminum yardstick. That way you have a good reference to use for the rest of your natural life.
I don't recall reading about anyone here who's recommended 1/16" accuracy, but I could have missed them...
I once had the job of cutting slots on a finished neck that had filled slots to make a flush fret neck. My old slotting setup used a small tile saw (the kind that looks like a small circular saw) fitted with a 2-3/4" diameter .023" slotting blade. I made a precision guide by adding a maple guide across a 1/4" birch plywood panel and ran the saw along the guide to cut the guide to width. I used multiple layers of heavy duty double sided tape along the bottom to mate up with the neck edges. That allowed the guide to be positioned and held to the radiused fretboard exactly where I wanted to slot to be cut, in this case directly over the flush frets. The guide provided plenty of surface area against the fretboard to hold it firmly in position. It worked well for cutting the slots to install new frets.
I did have a photo that I sent to the person having the work done, but couldn't find it among the thousands of photos on my computer. Hopefully the verbaige is easy enough to understand.
That would have worked well for slotting the multi-scale board referred to in the multi-scale board slotting topic.
I much prefer transferring the fret locations from a printed layout guide directly to the work and then extending the marked line across the board with a precision square. Applied paper is too fussy and messy IMHO. When you produce an accurately printed layout guide it's even better to transfer it to the backside of a cheap aluminum yardstick. That way you have a good reference to use for the rest of your natural life.
I don't recall reading about anyone here who's recommended 1/16" accuracy, but I could have missed them...
I once had the job of cutting slots on a finished neck that had filled slots to make a flush fret neck. My old slotting setup used a small tile saw (the kind that looks like a small circular saw) fitted with a 2-3/4" diameter .023" slotting blade. I made a precision guide by adding a maple guide across a 1/4" birch plywood panel and ran the saw along the guide to cut the guide to width. I used multiple layers of heavy duty double sided tape along the bottom to mate up with the neck edges. That allowed the guide to be positioned and held to the radiused fretboard exactly where I wanted to slot to be cut, in this case directly over the flush frets. The guide provided plenty of surface area against the fretboard to hold it firmly in position. It worked well for cutting the slots to install new frets.
I did have a photo that I sent to the person having the work done, but couldn't find it among the thousands of photos on my computer. Hopefully the verbaige is easy enough to understand.
That would have worked well for slotting the multi-scale board referred to in the multi-scale board slotting topic.
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Ok, I have questions...
I recently switched from my home made miter box to the StewMac version and did not initially consider it a major improvement. I was using the SM fret template with my miter box so I considered the spacing accurate and I could get clean, straight slots. If the necessary tolerance is .005" than maybe the SM miter box is better/more accurate.
To my questions;
1 - if the fret slots are within the +/- .005 tolerance, wouldn't the fret crowning also have to be within that tolerance to maintain that level of accuracy?
2 - if the above is correct, then how can you make sure the the fret crowns are within tolerance? Surely one or two swipes with a crowning file could remove enough material to blow the tolerances?
3 - how do you measure the accuracy?
I recently switched from my home made miter box to the StewMac version and did not initially consider it a major improvement. I was using the SM fret template with my miter box so I considered the spacing accurate and I could get clean, straight slots. If the necessary tolerance is .005" than maybe the SM miter box is better/more accurate.
To my questions;
1 - if the fret slots are within the +/- .005 tolerance, wouldn't the fret crowning also have to be within that tolerance to maintain that level of accuracy?
2 - if the above is correct, then how can you make sure the the fret crowns are within tolerance? Surely one or two swipes with a crowning file could remove enough material to blow the tolerances?
3 - how do you measure the accuracy?
1. & 2. Yes, the frets all have to be crowned accurately too, for the intonation to be correct. The frets need to be crowned symmetrically, rounded equally on the front and back sides. The narrow flat strip on the top needs to be centered over the tang (and slot). And, the flat strip should be equal width on all the frets.
This is a big reason why the commercial concave crowning files are popular; they cut both sides of the fret at the same time and will almost always cut the crown symmetrically. The old-school technique of crowning the front and back sides separately with one side of a triangle file means that you have to be careful to do it evenly, and not make the crown asymmetric.
3. I personally measure the location of fret slots using my own precision Scale Rulers. These are special aluminum rulers that have scribed lines at all the fret locations, for a particular scale length. I've made up about 30 of them over the years, of different scale lengths. These rulers go in my slotting saw/machine and are what set the positions of the carriage for the cuts. Then I can remove the ruler from the machine and hold it right up against the fingerboard to check the positions of the slots.
I make the scale rulers using a special rig that I made years ago. I found a 40" vernier height gauge at a surplus place. I took off its big cast iron base and laid it down in a wood cradle frame. The blank aluminum bars attach to the frame and the head slides over them. I can accurately scribe lines on the aluminum bars to 0.001" or 0.05mm resolution over a 40" range. With it, I can make up any kind of custom rulers I want, with an Excel spreadsheet and some patience. A vernier measuring device is old-school and slow, but it's very accurate and reliable. No stinkin' sensors or computer chips or batteries.
Assuming that you don't have one of these
unsure, you can measure your fret slot position with a standard 24" Machinist's Ruler, preferably one graduated on one side in 100ths. We talked about them over on the other thread about rulers. On a 100th ruler, the smallest lines are 0.010" apart. Look with your magnifiers and see how the slot is positioned in relation to a pair of the lines. And you can interpolate the third digit.
1. & 2. Yes, the frets all have to be crowned accurately too, for the intonation to be correct. The frets need to be crowned symmetrically, rounded equally on the front and back sides. The narrow flat strip on the top needs to be centered over the tang (and slot). And, the flat strip should be equal width on all the frets.
This is a big reason why the commercial concave crowning files are popular; they cut both sides of the fret at the same time and will almost always cut the crown symmetrically. The old-school technique of crowning the front and back sides separately with one side of a triangle file means that you have to be careful to do it evenly, and not make the crown asymmetric.
3. I personally measure the location of fret slots using my own precision Scale Rulers. These are special aluminum rulers that have scribed lines at all the fret locations, for a particular scale length. I've made up about 30 of them over the years, of different scale lengths. These rulers go in my slotting saw/machine and are what set the positions of the carriage for the cuts. Then I can remove the ruler from the machine and hold it right up against the fingerboard to check the positions of the slots.
I make the scale rulers using a special rig that I made years ago. I found a 40" vernier height gauge at a surplus place. I took off its big cast iron base and laid it down in a wood cradle frame. The blank aluminum bars attach to the frame and the head slides over them. I can accurately scribe lines on the aluminum bars to 0.001" or 0.05mm resolution over a 40" range. With it, I can make up any kind of custom rulers I want, with an Excel spreadsheet and some patience. A vernier measuring device is old-school and slow, but it's very accurate and reliable. No stinkin' sensors or computer chips or batteries.
View attachment 5021380
View attachment 5021381
Assuming that you don't have one of these
Ok, so checking the accuracy of the fret slots is done visually with the machinist's ruler or a vernier's gauge (if you have one).
So, to bring this back to the OP's topic: using the StewMac miter box, saw and slotting templates should get accurate fret slot spacing, provided the tool set-up is precise and you use good technique. I guess at that point the fret crown accuracy can be referenced off the slot.
Now I need to get a machinist's ruler...
Thanks for answering all my questions; I seem to have a lot of them...
Ok, so checking the accuracy of the fret slots is done visually with the machinist's ruler or a vernier's gauge (if you have one).
So, to bring this back to the OP's topic: using the StewMac miter box, saw and slotting templates should get accurate fret slot spacing, provided the tool set-up is precise and you use good technique. I guess at that point the fret crown accuracy can be referenced off the slot.
Now I need to get a machinist's ruler...
Thanks for answering all my questions; I seem to have a lot of them...
You can also buy digital calipers in 24" length. That will reduce the annoying squinting and math when you lay out fret slots or make up your own rulers.
Here's a cheap import for $143:
https://www.amazon.com/Shars-Electronic-Caliper-Resolution-303-1545/dp/B0916D3XFF/ref=sr_1_6?crid=18HC4YV35W2BJ&keywords=digital+calipers+24+inch&qid=1680648840&sprefix=digital+calipers+24",aps,204&sr=8-6
Or here's a nicer Mitutoyo, with certificate, for a mere $802:
https://www.amazon.com/Mitutoyo-500-506-10-Digimatic-Stainless-Resolution/dp/B0002FS8G6/ref=sr_1_3?crid=18HC4YV35W2BJ&keywords=digital+calipers+24+inch&qid=1680649094&sprefix=digital+calipers+24",aps,204&sr=8-3&th=1
Or, forget the pesky electronic gizmos, and get an import 24" vernier caliper for $81:
https://www.amazon.com/DRINYOUNG-St...fos.006c50ae-5d4c-4777-9bc0-4513d670b6bc&th=1
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Yes, a Stew-Mac miter box can cut fret slots to an acceptable level of accuracy, if........
- Your fingerboard or neck is mounted solidly to the sled and doesn't have any deflection under side load...
- You use their slotting templates and the right size pin. Or some other accurately machined slotting template. And you clamp the sled down at each slot position.
- You adjust the miter box so that the rollers are fairly tight on the blade. It should roll smoothly, with some drag. And you should check to make sure it's square to the sled.
- Saw with gentle, straight strokes. Light strokes, clearing the dust, not applying any side load to the saw. If you push hard and dig in, something will deflect and throw the accuracy off.
I have the StewMac fret miter box. No issues, it does what it's supposed to do. I think it was money well spent, though admittedly, I got it several years ago -- I think I paid around $200.
I've used the SM miter box for the last 3 or 4 boards I've done; it works, but I wasn't sure it worked better than my home made miter box. Now I'm curious, I want to cross-check the accuracy between the two.
I would consider reinforcing the paper with a strip of clear tape before gluing. (I haven't actually tried this in instrument building, it's just what I'd consider doing.)
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