Search found 140 matches

by Trevor Gore
Thu Dec 14, 2017 6:05 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: side stiffners
Replies: 5
Views: 5510

Re: side stiffners

I've seen guitars move so much under humidity changes that back braces have been blown off and, in one extreme case of over humidification, where the back bindings had blown off at the butt end because the back panel had grown nearly 2mm along its length. That same guitar had evidence of gross under...
by Trevor Gore
Mon Dec 04, 2017 5:21 am
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: A guitar that rings - how?
Replies: 14
Views: 13814

Re: A guitar that rings - how?

To my surprise, I read the design book as saying that high impedance sides and a live back could work. Am I reading this right? Well, everything works to some extent, but, yes, high impedance sides and a live back work well, compared to run-of-the-mill guitars. As ever, you can't look at anything o...
by Trevor Gore
Fri Dec 01, 2017 1:06 am
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: A guitar that rings - how?
Replies: 14
Views: 13814

Re: A guitar that rings - how?

Doug, what matters are high impedance mismatches everywhere you don't want a wave to go, like out of the top and down the sides. Keeping the bending waves in the top keeps it ringing. High impedance mismatches reflect waves. Mass helps with an impedance mismatch more than stiffness does. So think ab...
by Trevor Gore
Tue Nov 07, 2017 11:02 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Reject wood guitar? Prototype?
Replies: 28
Views: 25910

Re: Reject wood guitar? Prototype?

Matthew Lau wrote:I was just thinking of experimenting with black shellac...
I did the one above in nitro. Just getting the pigment here was a major hassle. I got some just before reaching for a rattle can...
by Trevor Gore
Tue Nov 07, 2017 7:39 am
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Reject wood guitar? Prototype?
Replies: 28
Views: 25910

Re: Reject wood guitar? Prototype?

That's gorgeous! Thanks! In teh worse case scenario, I'll paint it black. Black paint is not really an easy way out. Most of my finishes are clear, so I asked a few guitar makers who do a lot more painting than me about how to go about a black finish. The unanimous advice was "don't do it"! They ha...
by Trevor Gore
Wed Nov 01, 2017 8:04 am
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Reject wood guitar? Prototype?
Replies: 28
Views: 25910

Re: Reject wood guitar? Prototype?

Professional guitar makers quite often have a "test mule" guitar or two, which new ideas are tested out on. I have a couple of guitars of different types that have had multiple tops on. If you do a decent job, very few people would be able to tell that a top (or back) had been changed. Here's one I ...
by Trevor Gore
Tue Aug 22, 2017 8:01 am
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Fret Crown Profile
Replies: 6
Views: 5562

Re: Fret Crown Profile

Interesting question. Many years ago, in my early experiments with intonation/compensation, I filed the frets on a guitar to a triangular profile (with a triangular file ;) ) with a pretty sharp top. IIRC, I didn't hear much (if any) difference to a normally profiled "new" fret. Recently, I've had a...
by Trevor Gore
Thu Mar 09, 2017 10:58 am
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: StewMac triple 0 with nylon strings?
Replies: 8
Views: 6429

Re: StewMac triple 0 with nylon strings?

...I'm just going to continue making the 000 the way it was intended and plan a classical for next time around. You made the right decision. I've long been of the opinion that most guitars are too big for their own good. A guitar that is 390mm across the lower bout (000 size) is way too big for a c...
by Trevor Gore
Thu Nov 19, 2015 5:05 am
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Concave fingerboard on vintage guitar
Replies: 7
Views: 4257

Re: Concave fingerboard on vintage guitar

If you end up pulling the frets, heating them with a soldering iron first often helps them come out and reduces the chipping. Even with non-oily woods like mahogany, the gunk collected around the frets over the years can be used to advantage...
by Trevor Gore
Thu Aug 20, 2015 7:19 am
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Side/rib reinforcements- when/where/how many?
Replies: 40
Views: 27352

Re: Side/rib reinforcements- when/where/how many?

Alan Carruth wrote:They were Australian imports, with some sort of soft local wood for the B&S,...
:shock:

I didn't think we did soft!

Most of the stuff around here you can't drive masonry nails into once it's dry!
by Trevor Gore
Sun Jul 26, 2015 7:55 am
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Compensated nut location: how does it relate to compensation at the saddle
Replies: 16
Views: 8502

Re: Compensated nut location: how does it relate to compensation at the saddle

I wonder why Doug chose to start the iteration by measuring pitch at the 5th fret, rather than a lower one. When I do this "properly" I run an optimisation routine that covers all the frets I want to incorporate (usually 0-12 on strings 4, 5 and 6 and 0-18 on strings 1-3; no point in forcing a sub-...
by Trevor Gore
Thu Jul 16, 2015 9:59 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Intonation: How Much Change in Scale Length Per Cent of Pitch Change at 12th?
Replies: 10
Views: 4697

Re: Intonation: How Much Change in Scale Length Per Cent of Pitch Change at 12th?

Trevor - I am guessing you must have posted something on the subject that clarified things for my friend, as I just got a note from her to the effect of "...never mind - Trevor Gore posted something - got it now'. Yep. The argument goes something like this: Tune the string Measure the cents error a...
by Trevor Gore
Sun Jun 21, 2015 9:43 am
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Optimum thickness for red cedar soundboard?
Replies: 21
Views: 16418

Re: Optimum thickness for red cedar soundboard?

Doug Shaker wrote:Just fishing around with the numbers it looks like you want the thickness in millimeters to be the cube root of 190000/[Young's modulus of the wood].
Needs some work on the decimal point ;).
by Trevor Gore
Sun Jun 21, 2015 9:39 am
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Optimum thickness for red cedar soundboard?
Replies: 21
Views: 16418

Re: Optimum thickness for red cedar soundboard?

I'm building a 000 12-fret with a western red cedar top. It's currently just a shade over 3mm thick. I've gotten two conflicting opinions from luthiers about what the optimum thickness should be: one says 3.5 mm and the other says 2.5 mm. What has your experience been with this material? As other h...
by Trevor Gore
Fri Apr 24, 2015 10:38 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: How different guitar woods sound? - Online Tests
Replies: 32
Views: 27629

Re: How different guitar woods sound? - Online Tests

Like many of the other respondents, I have so many problems with this experiment that it is difficult to know where to start. I think you're asking the wrong question. I think it would be more useful to ask something along the lines of "How do we market alternative B&S woods so they become more acce...
by Trevor Gore
Wed Feb 25, 2015 8:42 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: My Classical Guitar analysis
Replies: 5
Views: 3324

Re: My Classical Guitar analysis

Assuming that picture is of #6 and #7, which is which? Guitar 7 with reverse fan bracing and Kasha placed soundhole. #7 on the right, I guess. Guitar Six- DEAD ON spot on in tune all over every fret Try as I might, I have found this impossible to achieve even with my best intonation and compensatio...
by Trevor Gore
Mon Feb 09, 2015 1:17 am
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Classical guitar string length
Replies: 5
Views: 3469

Re: Classical guitar string length

Don't build it without an allowance for saddle compensation (if you're not doing nut compensation). I've just fixed a guitar that had the front of the saddle at nominal scale length and not enough room on the saddle to do decent saddle-only compensation. For a standard 650mm scale length you should ...
by Trevor Gore
Sun Jan 18, 2015 7:28 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Top density
Replies: 7
Views: 3503

Re: Top density

To a reasonable extent, stiffness (as in Young's modulus) tracks density for the spruces. The flexural rigidity of a panel is directly proportional to Young's modulus and to its thickness cubed. So the stiffness increases very rapidly with thickness, which means that in most cases the low density, l...
by Trevor Gore
Thu Jan 08, 2015 7:00 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: When to spend money on wood
Replies: 10
Views: 4110

Re: When to spend money on wood

It's much more to do with how you use it rather than how much you spend on it.

Lots of good sounding instruments have been made from reclaimed wood that has been saved from a dumpster. Whether you like the aesthetic is a different matter...