Fret slot tolerences

tjclem · #1 07-21-2010, 11:02 AM

So how tight do they need to be? I just compared 5 34 scale slotted boards and a paper template and was surprised at the differences.

Several of the boards were slotted at LMI even they were not all the same. Some slots were over 1/64" off between the boards. Has anybody else really compared boards they have gotten before? I didn't until now I just believed that what I bought was correct....t

vbasscustom · #2 07-21-2010, 11:31 AM

well i always slot my own, and i use digital calipers to get the job done true, but i suppose that in mass production of fretboards, even on high quality production basses would have flaws, and imperfections in th fret slots.

mikeyswood · #3 07-21-2010, 11:37 AM

A few thousandths would translate to a few cents off of the tone. Not much at all. There is no such thing as a perfectly intonated fretted instrument so as long as the slots are consistently off in the same direction you will be okay. If your slots are off short and long then you will have trouble.

Rickett Customs · #4 07-21-2010, 11:40 AM

Quote:

Originally Posted by vbasscustom

.......but i suppose that in mass production of fretboards, even on high quality production basses would have flaws, and imperfections in th fret slots.

Wrong, the big boys use gang saws. One cut done.

T-Bird · #5 07-21-2010, 11:41 AM

Hi.

Well IMO the question really is what's ones cutting repeatability and accuracy?

1/64" or 0.4mm for us metric folks sounds like a reasonable accuracy for a free-hand template.

I'm way too lazy ATM to calculate the pitch change for that said difference, but I'm relatively sure that I can't spot ~1/32" or 1mm variance. That doesn't mean that it isn't there and also it doesn't mean that I think no-one can spot it.

Regards
Sam

pilotjones · #6 07-21-2010, 04:21 PM

On a 34" scale, 1/64" off on the 12th fret makes you 1.6 cents off, on the 24th fret it makes you 3.2 cents off.
http://www.fretfind.ekips.org/origin...gtolerance.php

If all your slots are biased in the same direction, you're good to go, if you just have to bias the nut's witness point by the same amount in the same direction.

T-Bird · #7 07-21-2010, 11:21 PM

Hi.

Thanks for the link pilotjones.

Regards
Sam

pilotjones · #8 07-21-2010, 11:54 PM

Glad to be of service.

need4mospd · #9 07-22-2010, 08:22 AM

According to wikipedia, the "just notable difference" is 6 cents, which would come out to 1/32" difference at the 24th fret. I'd say if you fretted a bass at 1/64" tolerance, most musicians would not be able to perceive any difference, especially in a band setting. Solo playing where you would fret the same pitch on a different string at the same time is the only way you MIGHT perceive any difference.

This is purely theoretical talk.

tjclem · #10 07-22-2010, 08:26 AM

cool thanks

Musiclogic · #11 07-22-2010, 08:52 AM

something you need to do as you start getting templates, is to check them for accuracy when they arrive, I have had to send back 2 Stew Mac fretting templates(yes the steel ones) due to being more than 1/64th out, and 1 LMI template same way. If you are doing printed paper way, it's all on you...LOL

I now have a machine shop here do templates for me as I can afford them.

Diogenes · #12 07-22-2010, 01:26 PM

I made my own templates based on paper printouts and checked them with calipers. That way I know I'm getting a good quality template.

As for necks, I very rarely find the frets of even a mass produced bass that far out of tolerance.

JoeDeF · #13 07-22-2010, 10:33 PM

Quote:

Originally Posted by need4mospd

According to wikipedia, the "just notable difference" is 6 cents, which would come out to 1/32" difference at the 24th fret. I'd say if you fretted a bass at 1/64" tolerance, most musicians would not be able to perceive any difference, especially in a band setting. Solo playing where you would fret the same pitch on a different string at the same time is the only way you MIGHT perceive any difference.

This is purely theoretical talk.

To find out how inaccurate Wikipedia's take on just noticeable difference is, try the following:

The next time you are changing strings, put two G strings on (i.e. - replace the D string with another G - use the same brand and gauge if possible). Tune them with an electronic tuner so that they are six cents apart. Play the two open strings. In tune? Now, play them together while fretting the 20th fret. In tune? You'll probably find six cents to be much more than a just noticeable difference (assuming that you are a professional musician), especially in the higher range of the bass.

Now, it is true that in a busy arrangement or texture, some listeners and some musicians might not hear, say, a five cent difference at a particular moment. However, if you play a sustained note in "unison" with another instrument, say a synthesizer or Fender Rhodes, you will hear it.

I am a piano tuner. It is accepted (and proven by measurement) within our field that the very finest piano tuners limit error to about one third of a cent. That's 1/18 of Wikipedia's "just noticeable" difference! And, we consider a note to be out of tune if it is off by more than one cent (when grading a tuning, points are deducted at that threshold).

I'm not trying to be argumentative, but rather to encourage the highest level of accuracy possible when cutting fret slots.

pilotjones · #14 07-22-2010, 11:00 PM

Also, i believe there's a frequency dependence on just noticeable difference, with increased sensitivity in the upper registers.