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Questions: Dobro Plans

Questions: Dobro Plans

by Mike Dotson

Originally published in American Lutherie #87, 2006

 

Charlie S. from the Internet asks:

Can you give me a source for plans to build a Dobro?


Mike Dotson of Phoenix, AZ responds:

The only readily available plan for a resonator guitar I know of is the one by Paul Beard at Resophonic Outfitters. (www.beardguitars.com. Click “parts,” then “blueprints.”) They also supply all the parts needed. You can get the same plan as well as parts from Stewart-MacDonald (www.stewmac.com). ◆

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Letter: Experimental Violin

Letter: Experimental Violin

by Robert A. Edelstein

Originally published in American Lutherie #93, 2008



Hi Tim and GAL Staff,

I built this violin to be played at a Suzuki camp our family has attended for the past ten years. Both of our children are players. Just for fun, I tried to break every rule I could think of. The top of the instrument is made of eight pieces of 4" wide, 1/4" craft grade balsa from a hobby shop. I laminated them into two stacks of four boards each, then joined the two stacks side by side to make a blank 8" wide by 1" thick. Balsa is a pleasure to carve, but beware of chipping. The finished top was surprisingly resonant.

I used a carbon/graphite free-floating bass bar made from an old bow and slid into balsa blocks. It could be changed for stiffer or lighter ones depending on player preference. The soundpost is made to function as a very stiff spring; I wanted to see if it could “self adjust.” The neck is carved of mahogany and has a slide-through cam resting against the back which helps do a quick neck adjustment during construction. The headstock uses mini-tuners in a pattern suggestive of a traditional pegbox. For speed of completion, the back and sides are from a Stewart-MacDonald violin kit. Bessie Blum, an artist friend of ours in Cambridge, Massachusetts, did a wonderful decorative finish. The instrument plays well, but is a little top heavy from the mechanical tuners.

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Questions: Scale Length

Questions: Scale Length

by R.M. Mottola and Tim Olsen

Originally published in American Lutherie #93, 2008

 

Byron from the Internet asks:

Is there any way to determine the scale length of an instrument from a piece of the fingerboard? I have the fingerboard from an instrument that is currently being restored. The nut end had been trimmed, I think to accommodate some kind of odd nut.


The Questions column editor responds:

All inter-fret distances are related to scale length, so measuring, say, the distance between the 1st and 2nd fret and then looking that up on a fret scale chart will tell you the scale length. Or measure the distance between the 7th and 19th fret (assuming the instrument has a 19th fret of course) and multiply by three. The result will be within a few hundredths of the actual scale length, close enough to identify it.


American Lutherie editor Tim Olsen responds:

Imagine you put a capo on the 1st fret of a functional guitar. Measure from the 1st fret (now functioning as the nut) to the 13th (now functioning as the 12th), and double that to find the mathematical bridge point. If the fretboard is still on the guitar, you can find that point near the saddle and mark it. If the fretboard is not on the guitar, you can clamp it to something, like a 2×4, and mark the bridge point on that. Now you could easily find the nut point by measuring from the newly marked bridge point back to the 12th and doubling it. Confirm it by calculating the scale and checking the position of the individual frets. ◆

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It Worked for Me: Veneer Scraper

It Worked for Me: Veneer Scraper

by Eugene Clark

Originally published in American Lutherie #73, 2003 and Big Red Book of American Lutherie Volume Seven, 2015



In the first episode of my two-part article on Spanish rosette construction (American Lutherie #71, Big Red Book of American Lutherie Volume Six), I described how important the sizing of the veneers is to the whole process, and showed the veneer scraper that I currently use. It uses a Stanley #90 bull-nosed shoulder plane. My first veneer scraper was a plane blade with a simple wooden holder, which, as I mentioned, is the type of tool that one might find in a Spanish shop. Jon Peterson had some questions about that tool, so I made one to show him.

The anvil block, opposite the cutting edge of the blade, needs to be hard and stable. I used a scrap of seasoned maple with the end grain (which is harder than long grain) towards the blade. The base and the blade holder are scrap softwood, but any solid, stable wood could be used. The anvil block is screwed to the base and can be removed when it needs to be resurfaced. The larger of the two blocks that hold the blade is glued and screwed to the base. The narrower block is then clamped in position with the blade in place, pilot holes are drilled and screws are installed. The fit of the blade will now be too tight, but by backing out those screws a little, the blade will slide freely, yet very little tightening of the wing nuts will hold the blade firmly. The width of the gap between the blade and the anvil block is adjusted by tapping with a hammer on the end of the tool or on the exposed end of the blade.

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Questions: Requinto Plans

Questions: Requinto Plans

by William Cumpiano and Luis Alberto Paredes Rodríguez

Originally published in American Lutherie #87, 2006

 

Chip H. from the Internet asks:

I’ve been looking everywhere for a set of plans for a requinto. Any thoughts on where I might find one, or some generous soul that might send me the dimensions and scale length?


William Cumpiano of Northampton, MA responds:

I doubt anyone has ever produced plans for a requinto, or at least offered one for commercial distribution. For most Hispanic luthiers I know, sharing information with strangers is a low priority. I’m an exception.

Requintos are made just like a Spanish guitar, with a smaller template but full guitar-depth sides. They are tuned like a guitar capoed at the 5th fret, A to A, with the same intervals between the strings as a guitar. Scales vary from 21 5/8" to 22 1/8". Cutaways are very popular. Thicknesses of all the top, back and side plates are the same as the ones chosen for the larger Spanish guitar. Five fan braces with two cutoff bars on the bottom are most common. Strings chosen are the same as for full-size guitars, but understandably the gauges on the lightest-tension sets are preferred. All other full-size guitar dimensions and construction details apply.


Luis Alberto Paredes Rodríguez from Bogotá, Colombia responds:

Here are the basic dimensions of the requintos we make in our shop. The body measurements are similar to those of the Colombian tiple: upper bout = 25CM; waist = 21.4CM; lower bout = 32.5CM; body length = 42CM; body depth = 9CM–9.5CM. The scale length varies from 540MM to 560MM. But we find the ideal scale to be 550MM. The other neck dimensions are the same as the guitar and the neck joins the body at the 12th fret. Some have a body cutaway. The instruments invariably have a pickguard. (Editor’s note: GAL Instrument Plan #51, the Colombian Tiple, was drawn by Sr. Paredes. It may be ordered from the GAL website.) ◆

(See also our Instrument Plan #54, Mexican Requinto)