Rule of 18 Fretboard

pshupe

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I'm whipping up a rule of 18 fret board for a friend of mine. Thought I'd share. As always, with anything 59 LP related. Whip out the Bartlett plans.

small-plans.jpg


Tom gives the fret spacing chart and dimension of the fretboard on his plans. So I just have to use his measurements and draw up the board in CAD. Draw each freet slot, nut width, taper, and inlay pockets. This should work for my Fusion 360 model so I can make my tool paths for the CNC machine.
rule of 18.JPG


Transfer into Fusion 360 and create a 3d model. Create all the necessary toolpaths to cut the board.

rule of 18 - fusion.JPG


I have 5 toolpaths, starting out with a parallel 3d surfacing procedure with a 1/2" ballnose bit with a modest stepover. Then I cut out the profile of the board. Next up inlay pockets, hogging out most with a 1/16" diameter bit and tracing around the edges of the curved route with a 0.024" diameter fret slotting bit for those nice sharp corners of the inlays. The final procedure is tracing the fret slots with that same bit. 9 passes at 0.01" doc will get the slots to the correct depth.

Copy these files onto a memory stick and we're ready to machine, once I select the fret board blank. Files to copy onto the stick. I number and name my toolpaths which include the size of bit required, so I don't mess it up.
toolpaths.JPG


My friend picked out one of the boards from my stock pile. It is actually one of the set I cut and used for my last build. Very nice chocolatey brown Madagascar Rosewood board. I have a few Braz boards in my stock pile and when I pick up wood at the local exotic wood place I always try and find Rosewood that is close. Here are 3 boards. Two Braz and one Madagascar. Great tap tone in all 3. Almost ready to make some sweet smelling dust.
IMG_1909.jpg


Cheers Peter.
 

moreles

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Hmmm... so a file, backsaw, and Dremel, used while working sitting on a bed in a house shared with friends, is not a setup likely to produce excellent intonation and an accurate build? I've gotten better than those early days, but I love hearing your process and setup. I don't think there a hand-tooler alive who can achieve the fretboard precision of this modern tooling. Very interesting!
 

pshupe

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Hmmm... so a file, backsaw, and Dremel, used while working sitting on a bed in a house shared with friends, is not a setup likely to produce excellent intonation and an accurate build? I've gotten better than those early days, but I love hearing your process and setup. I don't think there a hand-tooler alive who can achieve the fretboard precision of this modern tooling. Very interesting!
There may be but I doubt they could do it in less than an hour and cut 6 fret boards from a larger rough block at the same time. Cross cut, jointed, and re-sawed while I watched and listened for the CNC to do something silly. It did not.

These boards look much darker in person and should darken up once the air gets to them.

IMG_1959-lo.jpg


Cheers Peter.
 

ihavenofish

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Oooh, nice. I need to figure out the rule of 18 math to create a parametric fusion file. I have one for regular scales.

(whenever someone asks for a different scale I can just type in the number and whole file changes, inlays and all)
 

JBL Instruments

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Oooh, nice. I need to figure out the rule of 18 math to create a parametric fusion file. I have one for regular scales.

(whenever someone asks for a different scale I can just type in the number and whole file changes, inlays and all)
What formula are you currently using?

This works in Fusion and checks out with 17.817
d1*(1-(/(1.059463^(1))))
This formula is only for the 1st fret>
Make sure you get all the parentheses or Fusion will not accept the formula.

d1 is the reference parameter which you can always change 24.5625, 24.75, or 25.5 etc.
(If Fusion gives this reference a different number, example d27 for whatever reason, just use that number in the formula above.)

Copy and paste the formula into every fret location and change the last number to the corresponding fret.
The 7th fret formula will be d1*(1-(/(1.059463^(7))))
The 12th fret formula will be d1*(1-(/(1.059463^(12))))
So on and so forth...
 

ihavenofish

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I have one for 17.817 already. Obviously rule of 18 would just be measured out as "previous fret-(previous fret / 18)" from the bridge for spacing. however 18 is "weird", because the bridge is moved to compensate for it being technically wrong, so 24.75 becomes 24.625 or something of the like. Just need to determine that part and make it automatic.

Once I get there I want to make a little generator panel where the user can just type in the scale, number of frets, nut type, radius, widths, and "rule" and it will make a fretboard model inlays, markers and all referenced from the bridge.
 

JBL Instruments

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So the sketch would be basically the same but the formula much simpler. After the 1st fret the formula would be the reference parameter of the fret in front of it divided by 18 so d1-dX/18. I'm assuming you already know this but I thought I'd add to the info above for anyone reading this thread in the future.
 
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Brek

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I'm whipping up a rule of 18 fret board for a friend of mine. Thought I'd share. As always, with anything 59 LP related. Whip out the Bartlett plans.

View attachment 589997

Tom gives the fret spacing chart and dimension of the fretboard on his plans. So I just have to use his measurements and draw up the board in CAD. Draw each freet slot, nut width, taper, and inlay pockets. This should work for my Fusion 360 model so I can make my tool paths for the CNC machine.
View attachment 590000

Transfer into Fusion 360 and create a 3d model. Create all the necessary toolpaths to cut the board.

View attachment 589999

I have 5 toolpaths, starting out with a parallel 3d surfacing procedure with a 1/2" ballnose bit with a modest stepover. Then I cut out the profile of the board. Next up inlay pockets, hogging out most with a 1/16" diameter bit and tracing around the edges of the curved route with a 0.024" diameter fret slotting bit for those nice sharp corners of the inlays. The final procedure is tracing the fret slots with that same bit. 9 passes at 0.01" doc will get the slots to the correct depth.

Copy these files onto a memory stick and we're ready to machine, once I select the fret board blank. Files to copy onto the stick. I number and name my toolpaths which include the size of bit required, so I don't mess it up.
View attachment 590002

My friend picked out one of the boards from my stock pile. It is actually one of the set I cut and used for my last build. Very nice chocolatey brown Madagascar Rosewood board. I have a few Braz boards in my stock pile and when I pick up wood at the local exotic wood place I always try and find Rosewood that is close. Here are 3 boards. Two Braz and one Madagascar. Great tap tone in all 3. Almost ready to make some sweet smelling dust.
View attachment 590006

Cheers Peter.
very good of you. I have a quick question, I bought a fretboard that someone started and gave up on, look like they have used CA glue to glue frets on, and some is on fretboard, this is making me think return it, I am guessing it's not going to come off easily? a couple of small patches look like they have sunk in.
 

pshupe

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very good of you. I have a quick question, I bought a fretboard that someone started and gave up on, look like they have used CA glue to glue frets on, and some is on fretboard, this is making me think return it, I am guessing it's not going to come off easily? a couple of small patches look like they have sunk in.
Generally you can just scrape off with a sharp razor blade. Then sand with some sand paper. I have found that CA glue discolours the board substantially but once you sand it, even if it has sunk in, it looks fine. Others may want to comment. I have repaired a cracked board by flooding with CA and clamping. It was very discoloured and thought it was ruined. Once I sanded, it disappeared and was fine. Might depend on the board but that ihas been my limited experience.

Cheers Peter.
 
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ihavenofish

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So, I get a 24.672" rule of 18 scale, with the bridge at 24.75", with the 12th at 12.375".
Is that right? Seems to correspond to what I've read elsewhere.
 

Moodivarius

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I'm whipping up a rule of 18 fret board for a friend of mine. Thought I'd share. As always, with anything 59 LP related. Whip out the Bartlett plans.

View attachment 589997

Tom gives the fret spacing chart and dimension of the fretboard on his plans. So I just have to use his measurements and draw up the board in CAD. Draw each freet slot, nut width, taper, and inlay pockets. This should work for my Fusion 360 model so I can make my tool paths for the CNC machine.
View attachment 590000

Transfer into Fusion 360 and create a 3d model. Create all the necessary toolpaths to cut the board.

View attachment 589999

I have 5 toolpaths, starting out with a parallel 3d surfacing procedure with a 1/2" ballnose bit with a modest stepover. Then I cut out the profile of the board. Next up inlay pockets, hogging out most with a 1/16" diameter bit and tracing around the edges of the curved route with a 0.024" diameter fret slotting bit for those nice sharp corners of the inlays. The final procedure is tracing the fret slots with that same bit. 9 passes at 0.01" doc will get the slots to the correct depth.

Copy these files onto a memory stick and we're ready to machine, once I select the fret board blank. Files to copy onto the stick. I number and name my toolpaths which include the size of bit required, so I don't mess it up.
View attachment 590002

My friend picked out one of the boards from my stock pile. It is actually one of the set I cut and used for my last build. Very nice chocolatey brown Madagascar Rosewood board. I have a few Braz boards in my stock pile and when I pick up wood at the local exotic wood place I always try and find Rosewood that is close. Here are 3 boards. Two Braz and one Madagascar. Great tap tone in all 3. Almost ready to make some sweet smelling dust.
View attachment 590006

Cheers Peter.
Peter,

Where do you buy your inlays?

I bought some off eBay, & another set from Solo, & both different.
Which neither fit the inlay route I got. Purchased LP files from 3DCNCguitars.



Scott
 

ARandall

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Maybe contact the seller. Unless Peter has bought the same file it is unlikely he will know what the precise dimension you have.

If they are vintage shape, then Bartlett and Dave Johnson inlays both fit the rout and are accurate to the 'swirl pattern'.
 

Bainzy

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It's a shame many vendors sell inlays with different shapes. I recently got your template Pete and offered up some inlays I got in the UK, these are 'Incudo' from Rothko and Frost. All inlays are just a bit too narrow. I have some I bought 10 years ago from the US that are also too small (exact same shape), I think maybe they were from Philadelphia Luthier Tools?

One day I'll have to make a template or CAD file to match it for cutting inlays, as I'd like to be able to make them quickly in different materials and colours.
 

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pshupe

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It's a shame many vendors sell inlays with different shapes. I recently got your template Pete and offered up some inlays I got in the UK, these are 'Incudo' from Rothko and Frost. All inlays are just a bit too narrow. I have some I bought 10 years ago from the US that are also too small (exact same shape), I think maybe they were from Philadelphia Luthier Tools?

One day I'll have to make a template or CAD file to match it for cutting inlays, as I'd like to be able to make them quickly in different materials and colours.

You can use a smaller cutter If your inlays are consistently smaller all the way around. Bits of that size are usually 1/8" shank. If you purchase a 3/32" cutter with a 1/8" shank then this will tighten the route by 1/64" all the way around.

Cheers Peter.
 

pavel

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It's a shame many vendors sell inlays with different shapes. I recently got your template Pete and offered up some inlays I got in the UK, these are 'Incudo' from Rothko and Frost. All inlays are just a bit too narrow. I have some I bought 10 years ago from the US that are also too small (exact same shape), I think maybe they were from Philadelphia Luthier Tools?

One day I'll have to make a template or CAD file to match it for cutting inlays, as I'd like to be able to make them quickly in different materials and colours.
The inlays from Retrospec and from Tom Bartlett, respectively, both fit Peter's template really well and are a superior material that passes all the cork sniffing muster.

Rothko and Frost also sells pretty nice inlay blanks, I've been tempted to try to cut my own. Alas I don't have CNC ability, which I think would make it a whole lot easier to get precise cuts.
 

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