Search found 1313 matches

by Trevor Gore
Wed Jul 18, 2018 12:24 am
Forum: The Gallery
Topic: 12 fret BRW small body
Replies: 18
Views: 5410

Re: 12 fret BRW small body

Five years later (where did that go!) and in for a service. Gets frequently gigged, but well looked after. Fixed the pre-amp (the main reason for the visit), tap tested, tweaked the set-up, sorted some dings in the finish, a cut and buff and good for many more years. sDSCF0649.jpg sDSCF0653.jpg And ...
by Trevor Gore
Thu Jul 12, 2018 8:37 pm
Forum: Instrument Builders Forum
Topic: Converting the 14 fret J45 drawings for 12 fret?
Replies: 2
Views: 130

Re: Converting the 14 fret J45 drawings for 12 fret?

I'd be keeping the body the same, but for a 12th fret neck join use the layout style of the falcate design, with fretboard overhang etc., depending on how many frets you want. The falcate design is a different scale length from the J45, so remember to correct for that so that you get the sound hole ...
by Trevor Gore
Sun Jul 01, 2018 10:33 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Bolt on bolt off neck - order of operations
Replies: 16
Views: 701

Re: Bolt on bolt off neck - order of operations

There's a couple of things to think about... Decide how you want to seat the nut (Fig 5.3) then work from that and the position of the 14th fret. Don't assume that the scale length of the pre-cut board is the same as what's in the book! The "shoulder" line on the heel block needs to align with the 1...
by Trevor Gore
Sat Jun 30, 2018 12:54 pm
Forum: Instrument Builders Forum
Topic: Using Abalone
Replies: 15
Views: 715

Re: Using Abalone

So do we have to get the shell inlay to exactly match the final surface of the top? Or is there a way of thinning it down, maybe with fine abrasives? And a follow up: how do we deal with the ineveitable small gaps? CA glue? So we have to flood with shellac first so as to not stain the spruce? Confu...
by Trevor Gore
Tue Jun 26, 2018 6:20 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Mass Support Block - Positioning
Replies: 4
Views: 245

Re: Mass Support Block - Positioning

You'd have to fill the guitar with coke to get the same weight as a couple of metal side weights :mrgreen: I guess the side masses will look a bit weird on the Xrays... 2nd anecdote: I was traveling with a guitar through LHR. Picked up the guitar at the baggage carousel and found a neat round hole ...
by Trevor Gore
Mon Jun 25, 2018 7:33 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Mass Support Block - Positioning
Replies: 4
Views: 245

Re: Mass Support Block - Positioning

does it matter if the additional weights applied to the sides are both on the same side of the guitar... I frequently use added mass only on one side, usually the treble side, so no problem there. ...and does it matter if one of them is not in the middle of the side but nearer the top (or back)? Th...
by Trevor Gore
Mon Jun 25, 2018 4:36 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Bolt on bolt off neck - order of operations
Replies: 16
Views: 701

Re: Bolt on bolt off neck - order of operations

So, before gluing in the headblock, I could sand an approximate front to back angle, or I could just plane it when assembled in the mold. Best to just plane it in the mould, at least for your first. If you have everything sanded to fit the top dish, you know the geometry is heading the right way. T...
by Trevor Gore
Mon Jun 25, 2018 1:00 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Bolt on bolt off neck - order of operations
Replies: 16
Views: 701

Re: Bolt on bolt off neck - order of operations

At the moment, the headblock is too long. However, I assume it will need to be 2 or 3 mm longer on the back to accomodate the curve of the back when sanding if we don't want to alter the depth of the sides from the dimension on the plan. Is that correct? Yes. Does the bolt on/off top plate also nee...
by Trevor Gore
Wed Jun 20, 2018 8:58 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Bolt on bolt off neck - order of operations
Replies: 16
Views: 701

Re: Bolt on bolt off neck - order of operations

First a couple of principles to remember: 1) In this style of construction, the neck is set co-planar with the upper bout. So no gaps between a straight edge placed on the neck blank (no fret board) and the upper bout 2) The projection of a straight edge over the upper bout should clear the saddle l...
by Trevor Gore
Mon Jun 18, 2018 10:20 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Further J45 questions
Replies: 3
Views: 241

Re: Further J45 questions

1 I'm assuming the dimension of the bolt on/off headblock are a bit bigger that actually required and the 100 mm depth is to be trimmed to fit to the brace (78 mm or something like). Yes. The timber sizes in the book cover all the build options (4 models) in the plans. You lose height due to the cu...
by Trevor Gore
Thu Jun 14, 2018 8:20 pm
Forum: Tutorials
Topic: Cutting notches in braces
Replies: 4
Views: 601

Re: Cutting notches in braces

Nice one, Dave. I've used a router recently. Do both braces together and space them apart a bit so that the router is stable. Set the depth by sitting the router base on the bridge plate + CF and drop the bit to the bench. Ends of cuts defined with saw cuts, as usual. Using the depth stop is a good ...
by Trevor Gore
Tue Jun 12, 2018 12:14 am
Forum: Instrument Builders Forum
Topic: Broken drill bit in tie block
Replies: 6
Views: 470

Re: Broken drill bit in tie block

IF you managed to drill right through before it snapped AND you have a drill press... ...set up the bridge in a drill vise so that any hole aligns co-axially with the chuck. Put the busted part of the drill in the chuck, upside down. Using the drill stump as a drift, press the broken piece of drill ...
by Trevor Gore
Tue May 29, 2018 5:52 pm
Forum: Instrument Builders Forum
Topic: Reducing x-brace angle?
Replies: 11
Views: 721

Re: Reducing x-brace angle?

...So possibly Trev might come along and clarify how he measures his rotation... Like all simple methods of measurement (i.e. can be done in the average workshop/does not need a metrology lab), they're never quite as simple as they might look. The bridge rotation measurement method I wrote up in th...
by Trevor Gore
Sun May 20, 2018 10:39 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Tapping panels for thickness?
Replies: 6
Views: 583

Re: Tapping panels for thickness?

That's very low density and low stiffness redwood. Normally I'd expect Elong to be in the 10 GPa region. So if it feels stiff, as you say, it suggests something is wrong somewhere. If not, figure out the mass that the top panel would be and see if the low density compensates for the lack of stiffnes...
by Trevor Gore
Sat May 19, 2018 1:18 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Tapping panels for thickness?
Replies: 6
Views: 583

Re: Tapping panels for thickness?

Chris, the density seems very low for walnut at 395.9kg/m^3. ~570 kg/m^3 is fairly typical. Having said that, 2.3mm for a back panel thickness is fairly reasonable for a live back. Just a point of clarification... When using the Youngs Mod Dynamic Method formula, the actual measurements of the panel...
by Trevor Gore
Fri May 18, 2018 9:41 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Tapping panels for thickness?
Replies: 6
Views: 583

Re: Tapping panels for thickness?

Chris,

The "p" is ρ (Greek "rho") and is the symbol for density. See Fig 4.5-4.

There's more stuff on coding up Equ. 4.5-7 here and here. The typos have been fixed in the 2nd edition.
by Trevor Gore
Thu May 03, 2018 8:09 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Measuring top and back frequencies while voicing
Replies: 21
Views: 6774

Re: Measuring top and back frequencies while voicing

I was hoping someone else would chine in... Jim, do you mean adding Q in on a panel tap or a guitar box tap? You seem to be inferring a panel tap. If that's the case, the first thing to do is to determine what a Q measurement is: at a single frequency - a resonance governed by the panel dimensions, ...
by Trevor Gore
Thu May 03, 2018 8:51 am
Forum: Instrument Builders Forum
Topic: alternative fingerboard woods
Replies: 7
Views: 745

Re: alternative fingerboard woods

The stuff I have has worked quite easily. The grain does interlock, but nothing like as much as EIR, for example. Planed with the grain with a high angle plane will give a mirror-type finish. I've glued it with Titebond, fresh surfaces, no problem at all. Again, I've probably met more silica in EIR ...
by Trevor Gore
Wed May 02, 2018 9:13 am
Forum: Instrument Builders Forum
Topic: alternative fingerboard woods
Replies: 7
Views: 745

Re: alternative fingerboard woods

Brushbox is another that works really well for fretboards.
by Trevor Gore
Sun Apr 22, 2018 5:10 pm
Forum: Instrument Builders Forum
Topic: RIP Jim Williams
Replies: 4
Views: 650

Re: RIP Jim Williams

A sad loss indeed. He influenced many. One of the pioneers...
by Trevor Gore
Thu Apr 19, 2018 10:15 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Measuring top and back frequencies while voicing
Replies: 21
Views: 6774

Re: Measuring top and back frequencies while voicing

Yes, Brian tapes the back on and tests his guitars like that. But he has a few different steps to what's in "the book". You can see a pic of a taped on back here: http://brianburnsguitars.com/my-process (bottom of page). If my memory serves, he glues the bridge on before completing the finishing so ...
by Trevor Gore
Sun Apr 15, 2018 9:24 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Starting out on J45
Replies: 10
Views: 1042

Re: Starting out on J45

I do all assembly at 45% RH. The sides can be problematic because they tend to be heat and damp tortured and then ignored. They are often assembled at unknown RH and, mostly, people seem to get away with it. I tend to bend the sides early in the process and give them a week to normalise at 45% befor...
by Trevor Gore
Wed Apr 11, 2018 10:29 am
Forum: Instrument Builders Forum
Topic: Fingerboard Finish
Replies: 7
Views: 820

Re: Fingerboard Finish

There's a brief mention, penultimate paragraph, Build p 23-2. For rosewood or ebony, oil, preferably a drying one, used very sparingly. Some of the the non-drying ones just penetrate for ever and there is no telling where they will migrate to.
by Trevor Gore
Tue Apr 10, 2018 9:35 pm
Forum: Instrument Builders Forum
Topic: Trevor Gore interview by Matthew Ottley
Replies: 1
Views: 429

Trevor Gore interview by Matthew Ottley

It can be somewhat disconcerting when an acoustics professional gets in touch asking for an interview. But Matthew Ottley , as well as being an acoustics professional, is also one of us; he builds guitars. So I thought, "Why not?" Matthew visited me at The Shed and we talked for over an hour about a...
by Trevor Gore
Tue Apr 10, 2018 11:57 am
Forum: Instrument Builders Forum
Topic: Cutting 1mm slots / rings for rosettes
Replies: 15
Views: 1422

Re: Cutting 1mm slots / rings for rosettes

Trevor you mention third party high quality collets for the dewalt routers you use. A quick search doesn’t give an obvious supplier. Without getting too commercial where should we be looking - the cnc tooling people perhaps...? I was surprised to see the specs of such devices, the best are seriousl...