Search found 1265 matches

by Alan Carruth
Wed Mar 22, 2023 5:46 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Replace old ply back with solid wood?
Replies: 66
Views: 22635

Re: Replace old ply back with solid wood?

Properly done X-bracing should produce a better sound. I would not expect a large difference from replacing the back: most of the sound is in the top anyway.
by Alan Carruth
Wed Feb 22, 2023 12:15 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Improving Intonation on Guitar No. 2
Replies: 7
Views: 2209

Re: Improving Intonation on Guitar No. 2

You may also want to compensate the nut to get the best possible intonation, but doing so will change the break points at the saddle. There's a bit of leeway on this; Although in theory there's one 'right' answer a range of setting can work well enough. However you do it, intonation is about the las...
by Alan Carruth
Sat Feb 18, 2023 2:52 pm
Forum: Archtop Guitars and Bass Guitars
Topic: Smaller archtop bridge placement
Replies: 8
Views: 7573

Re: Smaller archtop bridge placement

Trying to calculate the 'main air' (Helmholtz' resonant pitch in advance is usually futile. The 'air'' mode couples with the motion of the top and back and all of the pitches get shifted depending on a range of factors. Moving the sound hole up into the corner like that is usually done to drop the '...
by Alan Carruth
Fri Feb 17, 2023 4:13 pm
Forum: Archtop Guitars and Bass Guitars
Topic: Smaller archtop bridge placement
Replies: 8
Views: 7573

Re: Smaller archtop bridge placement

If you're interested there's an Android app called 'Luthier Lab' written by a friend of mine, you might find helpful. You can draw out a shape for a guitar with it, and then open that shape in another module, which will calculate 'curtate cycloid' cross arches, and print out a full sized contour map...
by Alan Carruth
Thu Feb 16, 2023 5:46 pm
Forum: Archtop Guitars and Bass Guitars
Topic: Smaller archtop bridge placement
Replies: 8
Views: 7573

Re: Smaller archtop bridge placement

"My question is, would there be some benefit to designing the guitar so that the bridge is at the widest part of the lower bout?" Briefly, no. Even on flat top instruments there's really no need to get the bridge at the widest part of the bout. Even banjos aren't set up like that. Just as ...
by Alan Carruth
Fri Jan 27, 2023 5:41 pm
Forum: Wood and Materials Q&A
Topic: Using persimmon
Replies: 9
Views: 10994

Re: Using persimmon

Yes, it's good binding stock.

I've only gotten a couple of fingerboard pieces with black streaking; mostly it's grey.
by Alan Carruth
Sat Jan 21, 2023 6:45 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Side reinforcement strips
Replies: 9
Views: 7466

Re: Side reinforcement strips

I'd still run the ends under notched liners to avoid the stress riser.
by Alan Carruth
Thu Jan 19, 2023 3:07 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Small Body Maple Guitars.
Replies: 5
Views: 3601

Re: Small Body Maple Guitars.

With tops density is the key. Engelmann tends to be lower in density than other spruces on the average, but, as with all woods, there's a lot of variation. Some of the densest tops I've gotten were labeled 'Engelmann': without that I might have thought they were Red spruce. Since the long-grain stif...
by Alan Carruth
Mon Jan 16, 2023 12:54 pm
Forum: Archtop Guitars and Bass Guitars
Topic: about the dovetail neck joint
Replies: 7
Views: 9202

Re: about the dovetail neck joint

A number of Classical makers use a floating tenon the join the neck and body. The heel is cut to butt at the correct angle, mortices are made in both the heel and neck block, and a wood tenon goes into the mortices to locate everything. These are usually straight mortices, but there's no reason you ...
by Alan Carruth
Mon Jan 09, 2023 4:21 pm
Forum: Tools and Jigs
Topic: Dust Collection
Replies: 8
Views: 8368

Re: Dust Collection

My Oneida machine works well for the sanding table and joiner, but falls down on the bandsaw. The dust from that is moving too fast, and the big collector is set up for high volume/low velocity. I get better results on the bandsaw with a shop vac. On that I like to use the small Dust Deputy cyclone....
by Alan Carruth
Sat Dec 17, 2022 3:38 pm
Forum: Archtop Guitars and Bass Guitars
Topic: No f-holes?
Replies: 3
Views: 6141

Re: No f-holes?

Those two peaks, at 117 and 218 Hz are most likely the 'air' and 'top' parts of the 'bass reflex couple' between the top and the air in the box. If you tape over the holes and try again the 'air' resonance should go away, and the 'top' resonance should drop a bit in pitch. What I've found, using Chl...
by Alan Carruth
Fri Dec 16, 2022 12:43 pm
Forum: Archtop Guitars and Bass Guitars
Topic: No f-holes?
Replies: 3
Views: 6141

Re: No f-holes?

The holes are there mostly to provide a low pitched 'Helmholtz' type of air resonance, which reinforces the fundamentals of the note in it's vicinity acoustically. Depending on the size and location of the holes this could be pitched anywhere from about F on the low E to A# on the A string, with big...
by Alan Carruth
Mon Nov 21, 2022 12:24 pm
Forum: Glues and Finishes
Topic: old topic? Gluing bridge on top of finish?
Replies: 6
Views: 6199

Re: old topic? Gluing bridge on top of finish?

I do it similarly, except I mask a slightly smaller area, which reduces embarrassment if you misjudge the location a bit when taping. Scribe around the bridge and clean up just before you're ready to glue. I'm not a big fan of the rebate around the edge. The maximum stress on the glue line is along ...
by Alan Carruth
Sun Nov 20, 2022 4:30 pm
Forum: Glues and Finishes
Topic: old topic? Gluing bridge on top of finish?
Replies: 6
Views: 6199

Re: old topic? Gluing bridge on top of finish?

Ovation glues (or used to) the bridges on top of the finish. In their case, the finish was a full millimeter (.040") of epoxy. It's very hard, and difficult to remove gracefully with hand tools (DAMHIKT). Their bridges still do come up. FP is easy to remove, especially if you've masked off the ...
by Alan Carruth
Thu Oct 27, 2022 4:54 pm
Forum: Tools and Jigs
Topic: Planning a workbench, any tips?
Replies: 20
Views: 25635

Re: Planning a workbench, any tips?

Glenn:
You're about 40 minutes from me, in Newport, NH.

I've known several violin makers who basically worked out of a bedroom. Guitars take up a little more space, but not that much. The trick is to minimize power tools.
by Alan Carruth
Tue Oct 04, 2022 3:31 pm
Forum: Archtop Guitars and Bass Guitars
Topic: Alternative to X/Parallel bracing
Replies: 10
Views: 11581

Re: Alternative to X/Parallel bracing

On archtops you have some dials to turn that are not generally used on flat tops; in particular, arching and graduation. These provide a lot of the stiffness that a flat top gets from bracing. This can get quite subtle; arch shape and well as height can control the stiffness in different areas of th...
by Alan Carruth
Fri Sep 30, 2022 11:23 am
Forum: The Soundhole
Topic: Have you ever seen anything like this?
Replies: 11
Views: 22948

Re: Have you ever seen anything like this?

Fred Dickens did an experiment where he varied the depth of a guitar to see what happened to the 'main air' resonance. He started with sides 6" deep (in BRW!) and measured the air mode pitch. Then he cut the back off, reduced the side height by 1", and put it all back together, re-doing th...
by Alan Carruth
Sun Sep 25, 2022 4:43 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Side reinforcement strips
Replies: 9
Views: 7466

Re: Side reinforcement strips

Cloth side tapes work very well in resisting splits from knocks on the side. In measurements I made they increased the force required to crack a sample piece by about 50%. They also do a good job of stopping cracks from spreading, which simplifies repairs; the crack stops at the next tape, rather th...
by Alan Carruth
Wed Sep 21, 2022 5:16 pm
Forum: Glues and Finishes
Topic: Finishing a steel wool-and-vinegar application
Replies: 10
Views: 10981

Re: Finishing a steel wool-and-vinegar application

It's hardly surprising that this would work differently from other stains. Most stains are dyes or pigments that you apply to the surface. This works by a chemical reaction; the ferric acetate reacts with tannin to produce a black iron oxide within the wood itself. Various finishes could well alter ...
by Alan Carruth
Fri Sep 16, 2022 12:04 pm
Forum: Glues and Finishes
Topic: Finishing a steel wool-and-vinegar application
Replies: 10
Views: 10981

Re: Finishing a steel wool-and-vinegar application

Vinegar and iron, along with tannin, is the traditional permanent black dye. Depending on the strength of the various solutions you might get that, or just a 'sad' version of the wood color. Almost any finish over that will increase the color saturation, and end up darker. Water base finishes do tha...

Go to advanced search