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NMM 14381.  Guitar by National-Dobro Corporation, Chicago, 1936.
Duolian Style H. Serial number B223.
Gift of John McNeill, Springfield, South Dakota, 2009.

Front view Bass side view Treble side view Back view

Click on any image on this page to see a larger image

National-Dobro moved their operations to Chicago in 1936, the year this single-resonator guitar was made. The previous six years had been tumultuous for the company, which was originally founded in Los Angeles (1927) as the National Corporation to manufacture the triple-resonator guitars patented by John Dopyera. Following a dispute with George Beauchamp (the company’s general manager) and some shareholders, the Dopyera brothers left National to found their own company, Dobro, in 1929. In 1931, Louis Dopyera became a shareholder of National and increased his involvement in the company, leading to a merger of the two firms late in 1933.

Although the first patent for a single-resonator guitar appeared under George Beauchamp’s name, the Dopyeras also claimed to have been the inventors. The earliest version of this model was introduced by National in 1928 as the wood-bodied Triolian. The company began to produce a metal-bodied Triolian the following year. A cheaper version, the Duolian, was first offered in 1931, during the Great Depression.

The “hard baked finish of synthetic mahogany” on this guitar was described in a National catalog published about 1937: “The grain pattern was taken from a select piece of mahogany—and the result is a high-grade piano finish, depicting a fine mahogany grain which is beautiful as well as long lasting.”

Inscriptions:  Black-and-gold, shield-shaped decal on head: NATIONAL / DUOLIAN / MADE IN / U-S-A- [sic]

Branded on top of headstock, under finish: B 2 2 3

Views of Body

Front of guitar Bass side of guitar Treble side of guitar Back of guitar

Lower end of guitar

Body:  Soundboard: sheet steel; arched, pressed sheet-steel resonator plate affixed to resonator with six domed, slotted screws. Back: sheet steel; arched with recurve. Ribs: sheet steel, integral with back.

Trim:  Endpin: nickel-plated brass; steel domed, slot- headed screw through center. Finish: brown walnut-grain paint on body; shaded dark brown lacquer with fine craquelure on neck and head.

Front, Sides, and Back Views of Peghead

Front of peghead Bass side of peghead Treble side of peghead Back of peghead

Head: basswood. Neck: basswood; square profile for Hawaiian playing; integral with head. Tuners: six nickel-plated, Waverly worm-gear machine tuners with ivory plastic heads.

Views of Fretboard and Neck

Fretboard Bass side of neck Back of neck Treble side of neck

Fingerboard: rosewood; 19 nickel-silver frets; single ivoroid dots behind 5th, 7th, 9th, 12th, and 17th frets; double ivoroid dots behind 15th and 19th frets. Nut: bone; high setup for Hawaiian playing.

Neck Heel

Neck heel

Heel cap: none; neck heel set in from back.

Soundholes and Resonator

Soundholes Resonator

Bridge: steel staddle on black-painted biscuit (round steel cap on resonator); resonator cover plate has hand rest soldered to top, covering bridge position.

Tailpiece and Pickup

Tailpiece Pickup

Tailpiece: nickel-plated, pressed sheet steel.

Internal Structure

Linings:  none. Internal construction: extension of neck functions as large dowel stick on which resonator is mounted; two birch blocks braced between dowel stick and circular birch plywood platforms on upper and lower edges of resonator.


Measurements:  Total guitar length:  970 mm (38-3/16")
Back length:  462 mm (23-11/16")
Upper bout width:  258 mm (10-5/32")
Waist width:  221 mm (8-11/16")
Lower bout width:  358 mm (14-3/32")
Rib height (including edging) at heel:  73 mm (2-7/8")
Rib height, at waist:  78 mm (3-1/16")
Rib height, at end block:  83 mm (3-1/4")
Head length:  158 mm (6-9/32")
Head width, top:  72 mm (2-13/16")
Head width, bottom:  54 mm (2-1/8")
Neck length (nut to ribs):  349 mm (13-3/4")
Neck width, nut:  46 mm (1-13/16")
Neck width, heel:  57 mm (2-1/4")
Resonator plate diameter:  255 mm (10-1/32")
F-hole length:  126 mm (5-15/16")
Vibrating string length (nut to bridge edge):  top string:  634 mm (24-31/32"); bottom string:   637 mm (25-1/16")

Go to National-Dobro Checklist

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Most recent update: March 24, 2014

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