Official Luthiers Forum!

Hey everyone, thanks for all the good information. It has been helpful. To asnwer some of the concerns, I am aware of the dangers inherent in measuring fret to fret. Also, I personally dislike rulers of any sort for critical measurements, unless I am certain they have been calibrated for such, or are at least consistent.

In a past life, I worked with refrigerator compressors. In the engineering department, I was the tolerance stackup / GD&T guy. It was my job to set datums and make sure everything was dimensioned properly. In that industry (now gone from this country, I'm sad to say) we routinely worked with tolerances that I didn't believe when I first started working there. As an example, all critical parts had to be meaasured at a specified temperature. Build a compressor with parts not at the right temps, and it would either destroy itself, or most often, lock up first time it ran. With tolerances that tight on critical dimensions, everything was digial, period. Gauges used were certified in various ways, including the old school way of using shadow graphs, if you old timers remember those things. Fantastic accuracy. The tools they used to check parts were pretty mind boggling.

But for now, at home without a job, I do the best I can. This morning I measured my boards again, and feel some better about them. Iused paper again, but fresh pieces held down with masking tape, no stretch and no adhesive. I have downloaded W-fret, and believe these are at least as good if not better because they are all in one run, no cutting and taping required. I spot checked a few dimensions with a dial caliper, so I am comfortable with using them. As Todd said, any discrepancy should at least be consistent.

So i carefully placed them on the boards, and checked everything with my magnifying glass. Not as good as I once had access too, but the best I have. I also used my 6" rule from Woodcraft, wich is in 1/32 graduations.

I would say now that the most I am out (eyeball again, but through the glass this time) is 1/64. On one board, the first fret is out that much, and it is toward the nut. This may be OK, from a compensation standpoint, what do you think?

There are a few others that don't line up perfectly, but they all seem to fall well within 1/64. When making the checks this morning, I set the paper templates for a 12th fret datum instead of the nut, and everything lined up much better. So I may need to adjust the nut distance slightly.

I am thinking at this point it may be OK to use these boards. Any more thoughts much appreciated!

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Phil

http://www.oleninstruments.com

"Those who tilt at windmills are only considered insane by those who can't see the dragon."

1/64 th is close to 0.4 mm in my money, a touch more than I am comfortable with. I'm not saying that I can hear the difference but the odd player might. I'd still use the board. Fret, level and nudge over the peak of the fret by a touch. It will then be as accurate as you need it.

I use paper templates for locating frets all the time. I have more trouble cutting the slots exactly on the marks than I do marking the board.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

Lot's of ruler options here. http://www.mcmaster.com/#rule-straightedges/=lowmry. A good precision 36" ruler is not cheap but should be under $100. I have a 36" ruler marked off in 100th's of an inch. I use for odd fretboards, full-size layout and other tasks.

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Steve Smith
"Music is what feelings sound like"

A bit of error accumulation by using paper pattern,transfer of line,location of the fretting saw. Accurately cut fretting patterns seem like a more logical way to go,or precut boards from LMI etc.
Tom

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A person who has never made a mistake has never made anything!!!

re: splitting lines in half

For the record, my new way of marking things, especially nut slots, is to intentionally widen my pencil line a bit. I do this because:

a) I never hit my mark exactly the first time with my pencil, and I got sick of erasing and trying again
b) I find it much easier to nail the dead center of a large mark than right on top of a skinny mark

So I mark close, and then I notice which way I'm off and I scribble until I'm off on the other side by the same amount. I find I can get the best accuracy like this, and if I miss again I just widen the mark on the first side again. I do the same thing when I want to split a gradation. I scribble in from both side until I hit the closest gradation, and then I just eyeball it down the middle. It's amazing how deadly accurate you can be splitting a small distance by eye, and for myself it's more accurate than trying to line up by pencil with a little sliver of gradation.

You can buy 2' digital calipers on fleabay for under a hundred bucks
http://www.ebay.com/itm/Carrera-Precision-24-Electronic-Digital-LCD-Vernier-Micrometer-Caliper-CP5924-/200899097962?pt=LH_DefaultDomain_0&hash=item2ec684f56a

Bob

regarding paper templates stretching, or contracting, due to RH.....i wonder how much difference a stainless steel rule would register in a 58F shop versus an 85F shop...? i bet it could be significant with regards to fret calcs

nyazzip: The expansion of a steel rule going from 58F to 85F is about .00017" per inch. Or about .002" for a 12" scale. Think that a tad bit more accurate then paper print outs.
Tom

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A person who has never made a mistake has never made anything!!!

thanks, i was just wondering; i thought it might be more than that!
...and by the way, my hypothetical example low was 58 Farenheit...58 Celsius would be a tad warm...

Regardless of the ruler, I think your method of scoring then going to successively larger cuts could be the bulk of the problem. Make a miter box, score a tick mark with a razor knife on one edge, line the saw up on one side of the score (don't try to center), and cut.

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http://www.chassonguitars.com

What Kent said.
L.

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Cut to size.....Beat to fit.....Paint to match.

Yes my previous post said C rather then F temps. We here in Canada have adapted C as our temp model. I don't like it but I guess it is stuck in my old head now. Sorry about that. The result still stands and will edit post.
Tom

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A person who has never made a mistake has never made anything!!!

See http://www.anzlf.com/viewtopic.php?f=24&t=5004 on the Australian / New Zealand Luthiers Forum for a nice and affordable fret slot cutting jig usable for any scale length.

Honestly. Clever though it is that's a lot of effort for something that is essentially a pretty simple operation, either by using hand tools or power tools. All you really need to do is produce one accurate rule or locating template for each scale. You don't really need to do that. Buy a pre slotted board and use that as your rule or locating template. After you have the rule/template slotting is quick.

I get my decimals confused.

I was thinking a hundredth

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Old growth, shmold growth!

....yet another great reason to use metric, because you're really never going to be discussing/thinking about anything smaller than 0.1mm, when it comes to guitars....inches are so large, they have to be broken down 3 decimal places....

"...yet another great reason to use metric, because you're really never going to be discussing/thinking about anything smaller than 0.1mm, when it comes to guitars....inches are so large, they have to be broken down 3 decimal places...."


Not if you use fractions....

ok, you can keep your 39/64".....i'll call it 15.5mm

I just finished making 6 different scale length templates with Wfret!
-Don't stretch the paper(maybe a little if you are 1/100 short)
-Use double sided tape(spray adhesive not good)
-Use a bright led light & magnifying glass
-Score marks as soon as all marks are spot on
-Cut shy of marks on tablesaw & file to finished mark
-Take your time

Todd: And I wonder how you know this ..........??
Tom

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A person who has never made a mistake has never made anything!!!

On my first (and, so far, my only ) guitar build, I got all anal about the fret spacing, and used my collection of engineering slip gauges (of which I have hundreds) to measure the slot locations, and used a sharp marking knife to score the center of the slot.

I used the StewMac fret spacing calculator and registered off a stop at the nut end (effectively, off the nut) and just added gauges as necessary. Took forever, but was actually quite enjoyable. I was using an unusual fret scale btw, 25.2".

Kent's tip about setting the saw to one side of the mark is excellent ...I actually centered the cut (or tried to) but it would have made much more sense to do it his way ...particularly as I was doing a poor man's nut compensation anyway by trimming off 1mm at the nut end of the board once all the slots had been cut.

When I first started building back in the 70's cutting fret slots for me was the most daunting task of the whole process. As a journeyman machinist I was use to working to close tolerances and could not accept marking from a scale and cutting the frets. Did not know what kind of accuracy was required and there were no machined fret cutting fixtures. Bill Lewis in Vancouver B.C. was shortly after to come up with a fret cutting jig before he sold out to Todd Taggard who started LMI and now runs Allied Luthiery. Rather then use JO blocks (slip gauges) as murrmac has done I had 3/8" dia. AL rods (20 in Number) that I used from a common data point and moved the board on a sled fixture. A bit of a pain but I felt it was accurate enough to do the job. Made my first dozen or so boards that way and it worked excellent. I stepped back from building guitars for a number of years and when I got back in LMI was precutting slots and have used them ever since. Lots of way to do this but I think the trick is know it's accurate enough. The proof is having a board that plays correctly but that's a long way from the actual cutting.
Tom

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A person who has never made a mistake has never made anything!!!