Slotting a fretboard (accuracy)

[DarkPenguin]

So,

Another project has me making a fretboard. (And then a neck and then...) I'm looking at StewMac's fret placement calculator and it is going to the thousandths of an inch. I don't know that I have the means to mark and/or slot a fret to that precision.

How close does this have to be?

 

[Cagey]

How good are your ears? Even a perfect guitar is never truly in tune, so tolerance necessarily enters into the equation. I've also found that using high gain or otherwise forcing distortion/harmonics causes the dissonance within chords to be more obvious. Anyway, I suspect those slot placement calculators/charts are accurate to unachievable decimal places just because they can be. High precision calculators are somewhere between cheap and free, so you can afford to play with numbers that don't matter. What if your home thermostat displayed temperature three places to the right of the decimal and the furnace tried to maintain that? It would be impossible, and it also wouldn't matter.

 

[DarkPenguin]

Cool. That pretty much matches my thoughts. Also, my pencil is like .5mm. (I think I have a .2 somewhere. That is hard to see.)

My sanding block from china arrived. (Still waiting on a bridge from china.) So I can give this a shot.

Thanks!

 

[DarkPenguin]

I hope this shows up right. The last column is the fret position to a resolution of 1/64ths as that is the resolution of my incra rulers.

1   1.431"   1.431" (nut-1)  1.431 1 0.431 1  7/16
 2   2.782"   1.351" (1-2)  2.782 2 0.782 2 25/32
 3   4.057"   1.275" (2-3)  4.057 4 0.057 4  1/16
 4   5.261"   1.203" (3-4)  5.261 5 0.261 5 17/64
 5   6.397"   1.136" (4-5)  6.397 6 0.397 6 25/64
 6   7.469"   1.072" (5-6)  7.469 7 0.469 7 15/32
 7   8.481"   1.012" (6-7)  8.481 8 0.481 8 31/64
 8   9.436"   0.955" (7-8)  9.436 9 0.436 9  7/16
 9   10.338"   0.902" (8-9)  10.338 10 0.338 10 11/32
 10   11.189"   0.851" (9-10)  11.189 11 0.189 11  3/16
 11   11.992"   0.803" (10-11)  11.992 11 0.992 11 63/64
 12*   12.750"   0.758" (11-12)  12.75 12 0.75         12  3/4
 13   13.466"   0.716" (12-13)  13.466 13 0.466 13 15/32
 14   14.141"   0.675" (13-14)  14.141 14 0.141 14  9/64
 15   14.779"   0.638" (14-15)  14.779 14 0.779 14 25/32
 16   15.380"   0.602" (15-16)  15.38 15 0.38         15  3/8
 17   15.948"   0.568" (16-17)  15.948 15 0.948 15 61/64
 18   16.484"   0.536" (17-18)  16.484 16 0.484 16 31/64
 19   16.990"   0.506" (18-19)  16.99 16 0.99         16 63/64
 20   17.468"   0.478" (19-20)  17.468 17 0.468 17 15/32
 21   17.919"   0.451" (20-21)  17.919 17 0.919 17 59/64
 22   18.344"   0.425" (21-22)  18.344 18 0.344 18 11/32

 

[Cagey]

Without a CNC machine, I seriously doubt anyone can cut slots in wood to better than 1/64 resolution. Even if you could, the fret/string contact surface area would likely be wider so the resolution is lost.

Incidentally, your chart is readable, but you did lose the alignment. The way to control/maintain alignment in a grid presentation like that is to use the HTML table tags (which are supported here), but that's a helluva lotta work for a message board post. It's easier to just punch data like that into a spreadsheet and take a regional screenshot of it, then post that.

 

[DarkPenguin]

I'm off by a saw width on one of the slots. Sigh. Filling with super glue and hoping the old slot will be covered by the fret.

Great learning experience with this project. Mostly in trying to keep a router from running away from you.

So this isn't too bad despite a couple router chunks taken from it. Plenty of time to screw it up worse than the fret spacing. Oh, and lets not discuss the access hole for the truss rod. Next one will be routed right out the ass end of the neck. Don't care how much of a pita that is to use.

I was working on a body, too. One wonders where it got to.

 

[DarkPenguin]

I moved the fret. Anywho, the frets I bought could not be cheaper.

Blurry images:

 

[Cagey]

We're always our own worst critics. I think it looks great.

 

[mayfly]

Ditto!  If that's your first try at this, then that's pretty damn good IMHO.  Pretty damn good for the 5'th or 6'th try as well!

 

[bagman67]

I can't spot the problem fret.  Looks like you got it sorted.

And by the way, that is a lovely slice of figured lumber you're using for the neck shaft.  What species? 

 

[DarkPenguin]

Thanks guys. It is hard to separate the final result from all the screw ups I had to fix to get there.

I've a huge list of things to do differently next time. They mostly involve registration of parts to make sure everything goes together right.

The neck blank is ambrosia maple I bought from Rockler for $4 a board foot. It was going to be a shelf but then I realized it was thick enough to make a neck out of and was figured. The fretboard is purple heart. I think that was $10 at rockler.