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Dobro Serial Number Dating

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  1. Guitar Serial Number Dating

HISTORY OF THE PRE-WAR DOBRO®
By Randy Getz
bgdobro@ptd.net

INTRODUCTION
In order to keep this in a manageable format and size, only wooden-bodied screen hole resonator guitars will be addressed in this article. It is, after all, the preferred instrument for a bluegrass band setting. Since so little information is available in one location concerning pre-war instruments, this is an effort to cover in-depth the guitars which fall into that category, which were made by the companies involved in their manufacture from 1928-1941.
Before we look at the various models produced by these companies, it is important to understand the following: Just when you think you have all the pertinent information about a particular model or event, along comes a variation in one thing or another which is totally unexpected. The most complimentary thing that can be said about the consistency of the companies in this pre-war era is that 'During this period of time, the companies were consistently inconsistent.'
We will start at taking a brief look at the history surrounding the companies that built the early Dobro® guitars. (As we go along, you'll find that some knowledge of this historical background is very helpful when you start attempting to identify various models of guitars.) We will then make a short study of the construction characteristics that were unique to the different production facilities and to different time periods and that help to make the identification of these early guitars possible. Then, finally, we'll take a look at the individual models that were in production during this pre-war era and discuss the many features that went into each of them.
You are sure to find the history and construction of the early Dobro® guitars to be an absorbing and fascinating subject, and you'll be surprised to find that the process of identifying these early instruments can be quite simple, provided you know what to look for-and by the time you've finished this article, you will know what to look for!
PART ONE: HOW IT ALL BEGAN
To better understand the many variables that played a part in the production of pre-war Dobro®'s, and that therefore are involved in recognizing and identifying these guitars and their date and point of manufacture, it is imperative that you learn a little of the background and history of the companies involved in the manufacture of these vintage instruments.
The wooden-body, resonator guitar as we know it today came about through of a series of events which occurred in the National String Instrument Company, which was formed in 1925 and co-owned by a Slovak immigrant family, the Dopyeras, along with several other investors.
The Dopyera brothers, of whom there were five-John, Robert, Rudolph (Rudy), Louis, and Emil (Ed)-were heavily involved in the National Company, both as inventors and investors. Because of internal frictions with other parties within the company, John and his younger brother Rudy divested all their interest in National-including patents which they held for National instruments-and left the company in 1928. They had been working for some time outside the company on a new-style resonator assembly, which they were quick to patent upon their departure from National. The result of this new invention is the resonator guitar, as we know it today.
The exact reason for naming their new guitar and company, Dobro®, is unclear, however this is what is known: There were five Dopyera brothers and the name has five letters; it is a contraction of Dopyera Brothers; and, in their native Slovak tongue, dobro is a literal form of the word for good. Since no written records were either kept or saved (At least, to date none have surfaced.) by the various companies involved in the manufacture of these instruments in the pre-war era, the information found here is from a variety of alternative sources. These sources include, among numerous others, old music company catalogs and interviews with members of the Dopyera family.
Throughout the late 1920's and early 1930's the Dobro® Corporation and National continued to manufacture guitars as separate companies, with National producing the famous Tricone and other metal-bodied guitars while Dobro® Corporation produced the wooden-bodied instrument we know today. During this period, which covered the late 20's and early 30's the Dopyera brothers, with the exception of John and Rudy, continued their affiliation with both companies, primarily through financial investments.
In 1932, in response to the depression and a subsequent reduced demand for its more expensive Tricone, National, in an attempt to remain competitive, began producing its own single-cone, wooden-bodied guitar. This guitar incorporated a biscuit-type resonator which differed significantly in design from the spider-style bridge/cone assembly incorporated into the Dobro® Corporation guitars of the period. Unfortunately for National, these new, more economical guitars did not immediately catch on with the public, and the company's sales continued their downward slide.
Dobro® Corp., on the other hand was experiencing exceptional sales during this period so much so that in late 1932, Regal of Chicago was licensed by Dobro® Corporation to produce guitars bearing both the Dobro® and Regal logos for sale east of the Mississippi. According to this licensing agreement, Dobro® Corporation would supply Regal with all the metal parts.
During this time Dobro®-and Regal, following their licensing-made wooden-body, resonator guitars under various names for many other business concerns. These included Kraftsman, Melobro and Radio Tone, among others. It is also speculated that, following their licensing, wooden bodies from Regal found their way to Dobro® Corporation. The reason for this speculation follows: Dobro® Corporation produced guitars with relatively thin bodies ranging from 2 7/8' at the top to 3 ¼' at the bottom; these are called shallow-bodied guitars and were representative of the early-California period prior to the involvement with Regal. After the association with Regal, deeper bodies began to appear on California-built guitars, with a depth of 3 1/4' at the top to 3 1/2' at the bottom. It is ironic that these deeper bodied guitars were consistently some of the better sounding guitars produced in California. All Regal-built guitars had a deeper body than any of the early California models.
Problems continued to plague the National Company from the late 1920's into the early 1930's and, in 1934, the Dopyera family gained control of the National String Instrument Company. Shortly thereafter, both companies were merged into a single entity called National-Dobro® Corporation, and both brands of instruments were produced under one roof. It has been reported that during this time a yellow line was painted down the floor dividing the manufacturing facility into two separate production lines. It is a known fact, however, that interchangeable parts such as necks, tuners, and tailpieces, were freely exchanged back and forth across that yellow line. Some of these exchanges will be discussed later, in the section addressing the various models.
During the middle 1930's, acoustic resonator guitars fell out of favor as electric guitars of various types were becoming the instruments of choice. In late 1936, the National-Dobro® Corporation moved its headquarters from Los Angeles to Chicago and, over the course of the next year, all final assembly was shifted there. Then, in August of 1937, National-Dobro® assigned ALL Dobro® production to Regal, who continued building wooden- bodied resonator guitars bearing both the Dobro® and Regal logos. From that time, production at National-Dobro® focused primarily on metal-bodied and electric instruments. The only wooden-bodied instruments produced at the National-Dobro® facilities during these later years were National guitars. Throughout this period, all metal parts continued to be produced by suppliers in California, including the old National-Dobro® plant in Los Angeles. America's entry into World War II marked the end of this chapter of the resonator guitar's history. All production at both National-Dobro® and Regal ceased in 1941, as the metals used in the manufacture of these guitars were required for the war effort.
Note: If you are interested in learning more about resonator guitar history there is a wonderful book, by Bob Brozman, titled 'The History and Artistry of National Resonator Instruments,' published by Center Steam Publishing.
PART TWO: CONSTRUCTION FEATURES
Now that we have familiarized ourselves with the backgrounds of the companies involved in the manufacture of pre-war resonator guitars, we can take an in-depth look at the various construction features that can be used to identify these vintage instruments.
NECKS
Necks were made of mahogany, basswood, and non-descript hardwoods. On top-of-the-line walnut models, the necks were also made of walnut. Although most joined the body at the 12th fret, 14-fret instruments were not uncommon. Just as there were roundneck and squareneck 12-fret guitars, the 14-fret instruments were also available in both roundneck and squareneck models. During interviews, the Dopyeras have stated that all 14-fret instruments were made by Regal. This assertion has been called into question, however, as numerous 14-fret instruments (both roundneck and squareneck) have surfaced displaying features which can be attributed to the McKinley Avenue plant in Los Angeles.
The two basic types of necks came in many different shapes and configurations, leading to speculation that neck blanks were purchased from a variety of suppliers and then finished in-house to the required specifications. Roundnecks on some high-end models (Model 37 and above) may have a celluloid cap on the neck heel, while walnut-model roundnecks had a black heart in this heel cap. Most, if not all, California-built, squareneck guitars had a full-width heel (The heel of the neck was the same width as at the fretboard.) Chicago-built squarenecks traditionally had a tapered heel.
Necks had an extension rod which ran into body of the guitar, extending to just inside the soundwell where a screw attached it to a block of wood, thus securing it to the back of the guitar. This was used as the means of attaching the neck to the body. Shims were used between the neck extension and the block of wood to achieve a tight neck-to-body joint and provide for a slight amount of backset on the neck. For the most part, necks were plain except for sunbursts. The exceptions to this were the squarenecks on high-end walnut models (Model 156 and higher), which had binding inlaid along the length of the neck on both sides, similar to an outline pattern. The heel of the necks on California-built guitars extended to a point within 1/8'-1/4' of being flush with the back of the guitar, while Chicago-built guitar neck heels seldom, if ever, extended this close to the back.
FRETBOARDS
Fretboards were made of red bean wood, Makkochuba, rosewood and ebony or ebonized wood, with the model and time period of manufacture determining the material used. Red bean was used on several early, California-built models, while Makkochuba was used only on one model, which was also built in California. By early 1930, both red bean and
Makkochuba were replaced by rosewood. Rosewood was used throughout the production years, with ebony or ebonized wood used on Model 45s and above and on all walnut models. Frets on both roundneck and squareneck models were traditionally raised; however, a very few squareneck models have been seen with flush frets.
Position markers were located as follows: single dots at the 5th, 7th, 9th, 12th, and 17th, frets; and double dots at the 15th and 19th frets. The most common markers were MOP, with a couple of different sizes commonly used. On early guitars (up until about 1930) there was no marker at the 17th fret. High-end walnut guitars can be found with either dots or ornamental position markers, the latter predominately diamond-shaped. The double 'markers covered four screw heads which held the fretboard securely to the ~top of the guitar. Fretboards on Model 37's and above were usually bound in white celluloid, with some binding inlaid with side markers.
PEGHEADS
All pegheads on full-size California-built guitars were slotted, while those on tenor guitars were solid. On early models (until about 1934), the slots were cut with a special saw, which produced a squared-end in the slot. Upon merger with National and the subsequent move to a single building, this saw became misplaced (or discarded) and from that time all California-built guitars had routed slots which penetrated the peghead at an angle and had rounded ends. Regal-produced guitars also had routed slots. These slots, however, were slightly wider than those on California-built guitars and went straight through the peghead. They are, therefore, easily identifiable. The solid peghead did not appear until late in 1937, by which time all final production had been shifted to Chicago. Solid pegheads appear to have been used on Chicago-built, Model 37 and Model 45 guitars and appear on late Model27/32's. Many solid pegheads had sleeves where the tuning post penetrated the peghead, while others were produced without these sleeves.
PEGHEAD LOGOS
There were two logos which might be found on these early guitars, either the Dobro® logo or the Regal logo. All California-built guitars bear the Dobro® logo, while Chicago-built guitars might have either. The Dobro® logo was designed to represent a lyre (an ancient stringed musical instrument) while the Regal logo is a crown astride an oval inside which the word Regal is written.
Very early Dobro® logos had a gold border, but very few of these are seen. The predominant logo had a red border and is by far the most common. It is estimated that the switch to a red-bordered logo took place in 1929. The pre-war logo is very similar to the current logo with only a few exceptions. The red color on prewar logos was a bright red compared to the darker shade in use today. Unlike the current logo, the pre-war logo had no ® on the right side. (Some early 70's logos may be seen without the ®, but the color is still the darker red.) The width of the letters on pre-war logos was thinner than that of the letters found on current logos. Dobro® logos on higher-end guitars-usually Model 86 and above- were made of celluloid or MOP, (MOP was usually reserved for Models 150 and higher.), and inlaid into the peghead. These logos consisted of black lettering and design on a white or cream-colored background.
The Regal logo consisted of a crown in green, gold and black astride the upper portion of a green oval, which is bordered in a black/orange/black I border. The word Regal is written inside the oval in gold letters, with a black outline around the letter.
TUNERS
Slotted headstock tuners were normally three-on-a-plate with open gears and had either black or white plastic tuning buttons. Very few, if any, original tuners of any type are thought to have had metal buttons. Higher-end guitars (Models 45 and above) may be found with MOP tuning buttons. The backing plates were, for the most part, plain nickel-plated steel with no engraving or ornamentation. On higher-end, California-built guitars (Model 45 and above), a backing plate with stamped detail and figured ends was used. These same tuners were also found on some National models of the same time period. On the walnut models with gold-plated hardware, these figured tuning plates were also gold-plated. The tuning buttons could be pointed either up or down, depending on players preferences.
Solid-head tuners were either three-on-a-plate or single tuners of the open-back design. The tuning post peghead penetration may or may not have been fitted with sleeves. Tuning buttons were generally black or white plastic, although some Model 45 guitars were manufactured with pearlized tuning buttons. Some late three-on-a-plate tuners were covered with a metal shield (late Regal mfg).
Serial Numbers
Later in this article will be found a listing of serial numbers and the approximate years of manufacture, so we will not repeat it here. What will be discussed are the serial numbers in general and their use. No pre-war, screen hole resonator guitar has ever been found with a serial number exceeding four digits. Yet, in various interviews, John Dopyera has stated that production in the early-California period exceeded 600 guitars a month. Simple math tells us that this would mean that within two years serial numbers of over four digits would be required-or would it?
The Dobro® Corporation built guitars for many other vendors under many other names and few, if any, of these guitars had serial numbers. They would, however, have been included in the total production figure of over 600 guitars per month. So, with this in mind, it is possible that there were less than 10,000 screen hole Dobro® guitars built by Dobro® Corporation and upon their consolidation, National-Dobro®. It is a known fact that once production was shifted to Chicago serial numbers were started over as 3-digit numbers, Numbers with an 'A prefix also appeared at that time. These numbers were made with smaller stamps than those used on California-built guitars and are, therefore, readily distinguishable. However, it also appears that the numbering of Chicago-built guitars was abandoned after a short period and cannot, therefore, be followed with any degree of accuracy.
SOUNDWELLS
Most of the guitars produced during this time period had a round laminated wooden rim, called a soundwell, installed directly under the edge of the large opening on top of the guitar. The soundwell performed two functions: First, it provided an area on which the cone could rest, and second, it provided structural support for the top of the guitar.
The soundwell extended from the front to the back of the guitar and was attached to both with glue. To provide extra strength to these glued joints, kerfing was sometimes used, but as usual, without any consistency. It was sometimes located on the inside and outside of the soundwell or only on one side or the other. More often, it was omitted all together.
Soundwells were made in a variety of configurations. Some were made of relatively thin, 3/16' laminated wood, while others were made of heavier, wood laminate. Some soundwells had round holes; others had parallelogram-shaped holes. Still others had no holes at all except for the hole that the neck extension projected through. The number and size, as well as the placement of the round holes, varied throughout the entire production period. They numbered from as few as three to as many as 13. The soundwells with parallelogram holes were more consistent, with nine holes, and their placement was always the same.
Although there is debate over which configuration produced the best sounding instruments, it is generally agreed that, overtime, guitars with parallelogram-holed soundwells consistently produce the best tone and volume. There are, of course, many exceptions to this and it should not be considered a hard and fast rule. It has been noted that guitars with soundwells constructed of poplar wood tend to have good tone and volume with little regard to the hole type.
Some late 30's guitars made by Regal have no soundwells and these instruments tend to vary widely in regards to tone and volume.
CONES
The cone is one part of the heart of a resonator guitar and serves the same purpose as the cone in a modern day speaker, providing amplification of the resonance created when a string is plucked. The cones in pre-war Dobros® were made of a thin aluminum alloy and could be either spun or stamped (Pressed).
Spun cones were produced manually on a lathe by applying pressure to a spinning sheet of aluminum, then forcing it against a revolving form. Since this was a manual operation, the amount of pressure that was applied could vary from start to finish, and thereby produce a cone of unequal thickness. Because of this, many players feel that pre-war spun cones varied greatly in their tonal qualities
Stamped (pressed) cones, on the other hand, were produced by a totally mechanical process and the thickness never varied. For this reason, these cones shared more consistent tonal qualities. Stamped cones were made in two types; they were either plain, or had eight protrusions located about 3/4' below the top edges of the cone on the inside of the bowl. These latter cones were called lug cones.
Lug cones (and the modified spider bridge designed especially for use with them) were developed to address a couple of design problems. During this period, thousands of cheap, off-brand guitars were being built with inferior parts, and many of these had coverplates which offered little, if any, rise towards the coverplates center. This could create interference problems between the coverplate and the spider bridge assembly. Seating the spider lower inside the cone eliminated this interference. Also, the recent start of metal-body production by Dobro® presented yet another problem. These metal-body guitars had no soundwell. Rather, the cone sat on a lip formed when the top of the guitar was stamped. The cone simply didn't set as deeply inside the metal body of the guitar. This could also cause coverplate interference, which was alleviated through the use of these lug cones.
Resonator guitars were in very high demand during this period, and it proved simply impossible to produce spun cones in the needed quantities. Pressed cones were therefore introduced to help meet these growing demands. When interviewed, John Dopyera has stated that it was his opinion that, if both cones were made properly, there should be no variation in tonal qualities between a spun and a stamped cone. Spun cones had a definite bowl shape with circular grooves caused by the spinning operation whereas stamped cones had more of a flat side with metal wrinkles produced by the stamping process.
SPIDER BRIDGE
The spider bridge is the other part of the heart in a resonator guitar. It transmits the string vibrations to the cone for amplification. These bridges were cast of aluminum alloy and could be found in two configurations. Both had eight legs (there were some four leg spiders but these are not as desirable as an eight legged spider), which were the part of the spider bridge that makes contact with the cone. Some had long legs which rested on the inner lip of the cone, while others had short legs which rested on the eight lugs of the lug-type cone. Early spider bridges were almost flat, with very little rise towards the center area where the bridge was located, while later spiders had a small amount of rise towards a central hub in which the bridge slot was located. In [addition, each leg was connected by a web-like connector about halfway along each leg.
The most desirable pre-war spider bridge had a #14 cast into the central hub. This spider bridge is still available today and is used by most custom builders. It was thought that this spider bridge, in combination with a good cone, would produce consistently desirable tonal qualities.
NOTE: Dobro® Corp. and later National-Dobro® had no metal casting capabilities and the Company that cast the spiders for them identified this as their #14 casting thus the #14 on the spiders.
The spider bridges with the slight rise towards the central hub were developed after the higher rise coverplates were introduced. Long-legged spider bridges could be used with any of the cones described earlier; short-legged spider bridges, however, could only be used with the lug-type cone for which they were designed.
In the center of the spider bridge is located the bridge slot, a machined slot into which wooden bridges are inserted. In addition, there is also a hole in the center of the bridge slot through which a tension screw is inserted vertically. This tension screw holds the spider to the cone and provides for pre-tensioning the assembly.
COVERPLATES
The coverplate (sometimes sarcastically referred to as the 'hubcap') covered the resonator assembly to protect it from damage, and also provided a handrest to allow for the guitar to be played. Coverplate designs varied greatly, but we will only address those designs most commonly seen on the screen hole, wooden-body guitars.
There were three common patterns: the fan-style, the poinsettia-style, and the lesser-seen row-style.
The fan-style design-These consisted of three rows of openings in a fan-shaped pattern and placed at four equally-spaced locations. This was by far the most commonly-used coverplate. (There was also a fan-style pattern which consisted of four rows of openings, but this coverplate was designed for and primarily used on electric and metal-bodied guitars in the late 1930's.) These fan-style coverplates with three rows of holes were made in several styles and refined overtime. The earliest models were almost flat with very little rise towards the center palm rest, which covered the spider bridge. This coverplate had a wide outer flange where the screws which held it to the body were located. The screw positions on these very early coverplates were termed the 'clock position screws', as the screws were located at the positions of the numbers on a clock. With this type of positioning one screw was located under the instrument's tailpiece.
This low-rise, 'clock position' coverplate had some distinct disadvantages. Due to manufacturing variations in the various components which went under the coverplate, and due to its very low rise, these coverplates would often interfere with the spider bridge assembly. This required reworking the cone to make the resonator assembly sit lower in the guitar body. Another disadvantage was that, in order to remove the coverplate, the guitar had to be unstrung to gain access to the screw under the tailpiece.
These problems were solved by a series of modifications. The rise towards the center handrest was increased to eliminate the spider bridge-to coverplate interference. This was accomplished by taking the additional metal required for the additional height from the wide flange and, on these coverplates, the flange where the screws were located was narrowed considerably. Both the original coverplate design and this early modified version may be found with 'Pat Pen.' Stamped on the outer flange, and some of the earliest wide-flange plates may be void of anything. The screw position was handled by yet another modification, in which the rise was increased even more and the screw positions were changed so that there was no longer a screw located under the tail piece.
At this point there is a little conjecture regarding exactly how many modifications were made to these coverplates, but there were definitely three and possibly four. After the 'Pat Pend' series of coverplates, there were two patent numbers which appeared on future coverplates. The first was 1,872,633. This patent was issued in August, 1932, and was only used for approximately one year of production because in August of 1933, patent 1,896,484 was issued and this number appeared on all coverplates from the latter part of 1933 until the end of production. These patent numbers were located on the inner portion of the coverplates, at the edge of the opening for the spider bridge.
The poinsettia design - These coverplates appear to have come along following the association with Regal and are generally found on later production model guitars. Since this design was developed after the second patent was issued, they had the 1,896,484 number only. The poinsettia design consisted of four sets of six poinsettia petal-shaped openings arranged in a fan-shaped pattern and equally spaced around the coverplate.
The row-style design - This design was originally produced to be used on metal-bodied guitars, and consisted of four groups of two rows of eight rectangular slots, which were located equally around the coverplate. This particular design has shown up recently on some late Model 27, pre-war instruments.
The major distinction between the prewar fan-style coverplates and the modern fan-style coverplates is the lack of patent numbers on the newer ones. The old fan-style plates which had patent numbers also had an arrowhead type shape stamped at the end of the palmrest, which is absent from present-day models. (This arrowhead was also absent from the very early 'Patent Pend' coverplates.) Finally, today's coverplates have a higher rise than any of the standard coverplates which were designed to be used with the pre-war, wooden-bodied guitars.
Pre-war coverplates were made in a variety of finishes. These included painted, chrome-plated, nickel-plated and gold-plated versions, and they could be either plain or engraved. Nickel-plating was used on most guitars below Model 55's, with chrome-plated coverplates appearing on most models above the 55 and up to the 156, at which point they were gold-plated up to and including the top-of-the-line Model 206. Engraving began on later Model 86's. Early advertisements don't mention it, but later ones do. The same held true for some of the models above the Model 86. However, once you reached the gold-plated models, the engraving became a fact of life and only the amount of it increased as the model numbers increased. On Models 175 and above even the screen flanges were engraved and the cones and spiders on the Model 206 were anodized gold.
Again, it must be pointed out that there were many variations in what was done in those days, and combinations of any of the foregoing were possible.
TAILPIECES
The tailpiece was used to anchor the strings to the lower end of the guitar, opposite the peghead. California-built guitars utilized what is considered to be the standard Dobro® tailpiece, on which the strings attached to a sort of semi-circular edge. These were very similar to the tailpieces which are used on the resonator guitars being made today. The major differences were that the string spacing was slightly narrower than that found on today's instruments and the bulbous protrusion towards the bottom end of today's tailpieces was more pointed on pre-war guitars
Trapeze tailpieces were used by Regal and these came in a variety of styles. The finish on the tailpiece, like that on other exposed hardware, was matched to the finish on the coverplate.
NUTS/SPIDERS/BRIDGE INSERTS
The most common material used for nuts was bone and the spider bridge inserts were made either of boxwood or maple. Extension nuts were readily available so that a roundneck, Spanish style guitar could easily be converted to be played in the Hawaiian style. These extension nuts were made of die-cast metal and, sometimes, plated brass.
THE THREE HOLES
The three holes at the end of the fretboard were a part of an effort to make the top of the guitar resemble a lyre, as pictured in the company logo. On California-built guitars the tops of these holes were beveled, whereas most if not all Regal-built guitars had no beveled edges on the holes.
It should be noted that Model 27 guitars do not have these three holes. According to Tom Gray, who has done extensive research into the history of the Dobro®, Regal, in an effort to cut costs, made the suggestion to eliminate these holes on the Model 27, and National-Dobro® adopted this suggestion an a matter of policy.
Dobro® is a registered trademark of the Gibson Guitar Corporation. All trademarks and copyrights on this page are owned by their respective owners. Comments are owned by the Poster.
PART THREE: THE MODELS AS WE KNOW THEM
Now let's make an effort to describe the various pre-war models. These are listed in (approximately) chronological order to make it easier to follow their progression through the years
Note: Whenever more than one Model Number is listed, it is because at various periods of manufacture the Model Numbers were changed.
Model 36
This model is listed in very early advertisements and seems to disappear almost as fast as it appears it was initially the unbound student model 45, but was lowered in price with the following features: It was made of magnolia wood and finished in a semi-gloss, black, laquer. This is the only model which had a fretboard made of makkochuba. It also featured a silver, painted coverplate. This model was only available as a roundneck, and was an exclusive California-built, thin-body guitar. It was probably the low-end model at the time.
It was out of production by 1934.
Model 55/56
This model also appears in very early advertisements and literature, and has only been seen as a thin-bodied guitar with sawn slots, indicating that production was discontinued prior to the Dobro®/National consolidation. This guitar was constructed of three-ply birch and had a mahogany neck. Early fingerboards were made of red bean wood; later production models incorporated a rosewood fretboard. Its fretboard was bound in white celluloid binding and the instrument was available as a roundneck or squareneck. The entire guitar was finished in a dark, reddish brown semi-gloss that almost appears black. The body was unbound.
Production ended sometime in 1933 or 1934.
Models 60/65/66and 66B
These were known as 'carved models and had a design etched on the wooden body and the neck. The design was not 'carved', but rather was sandblasted using an overlay on which the design was cut out. The overlay was placed over the portion of the guitar to be etched and then sandblasted. The sandblasting would remove the top layer of wood exposed through the cutout portion of the overlay and leave the portion which the overlay covered. This model has been seen in both the early California thin-body design and in the deeper-body type which came along following the licensing of Regal. However, it has only been seen with sawn slots. Made of three-ply birch, the body was unbound. Early versions had a red bean wood fretboard, while later models were equipped with a rosewood fretboard. The Fretboards were bound in white celluloid. The finish applied to the undisturbed wood was of a very dark, almost ebony-looking color, while the sandblasted area was finished in a gray-almost greenish-gray-finish. The design on the back of the guitar included a ghoulish looking skull, which was changed in 1934 to show a letter D. These models were available as roundneck or squareneck instruments.
A variation of the Model 66 had binding on both the front and back of the body, as well as an ebony fretboard and was designated as the Model 66B.
These guitars were out of production by 1935.
Model 76
Bound top and back with ivoroid binding, this guitar was made of select, three-ply, white birch with a mahogany neck and an ebony fretboard also bound with ivoroid binding. This model had position dots on the binding sides along the fretboard as well as on the fretboard itself. It was finished in two-tone, hand-rubbed walnut semi-gloss. It was available in both roundneck and squareneck versions.
Production was discontinued by 1934.
Note: Regal introduced a Model 75 in 1937 which had a walnut body and an engraved coverplate, this particular model was only produced for a very brief time.
Models 85/86
This particular model is only known to exist as a thin-bodied, California-built guitar. The body was made of three-ply, ribbon-grained tabasco mahogany, with a mahogany neck. The fretboard was made of red bean wood, and bound with ivoroid binding. The body was bound top and back in three-layer, white/black/white binding, and the entire guitar was finished in a natural, reddish-brown, hand-rubbed finish. Early production models had a plain coverplate. Later versions had an engraved chrome coverplate. All known guitars of this model have two wooden bars, internally, which extend from the top of the guitar to the bottom, through the soundwell, and are glued to the back of the guitar. The purpose of these bars has never been fully understood. This model was available in both roundneck and squareneck versions.
Production of this model was discontinued by 1934.
THE WALNUT MODELS
Models 90/100/106
This was the lowest-end model of the walnut guitars, equipped with a black butt walnut body with a two-way, matched back and walnut neck. The fretboard was made of genuine ebony and bound with white ivoroid, and the body was bound top and back with three-layer, white/black/white binding. The entire guitar was finished in a natural, hand-rubbed satin finish. The coverplate was chrome-plated, and may be either plain or engraved; if engraved, the amount of engraving was minimal. Its' Dobro® logo was made of celluloid and inlaid into the peghead. This model was available as either roundneck or squareneck.
See the production history at end of the walnut-model listing.
Model 125
While this model does not appear in any advertisements, it was mentioned in correspondence with the Dopyeras. It is mentioned here because of the unique characteristics it displays. The body was constructed of five-ply, black butt walnut, and the neck was also walnut. The fingerboard was ebony, bound in ivoroid binding. The body was bound, top and back, in three-layer white/black/white binding. The back was four-way, book-matched, forming intricate patterns. The top was also four-way, book-matched, and the coverplate and tailpiece were chrome-plated and lightly engraved. 'Dobro-Deluxe was engraved on the palm rest. The entire guitar was finished in a natural, hand-rubbed, satin finish. The Dobro logo was made of celluloid and inlaid into the peghead. This model is only known to exist as a roundneck guitar.
See the production notes at the end of the section on walnut model guitars.
Models 155/156
This model had the same construction features as the Model 125, with the following exceptions: The back was of two-piece, book-matched walnut, and the guitar was finished in a hand-rubbed, natural dark walnut. The metal parts were gold-plated with engraving on the coverplate and tailpiece. The Tuning machine heads were MOP, as was the logo, which was inlaid into the peghead. The model was available in either a roundneck or squareneck version.
See the production notes at end of the section on walnut models.
Models 175/176
This model is another model that is not found in advertisements, but it is listed here because of its unique characteristics. It shares the same construction features as the Model 155/156, with the following exceptions: The back was of four-piece, bookmatched walnut, and the coverplate and tailpiece were more heavily engraved, as were the screen hole flanges. Even the sides of the neck have inlaid trim. This model is only known to exist as a squareneck, and it is possible that this guitar existed only as a special 'presentation' model.
Production notes at end of walnut model section.
Models 200/205/206
This was Dobro®'s top-of-the-line guitar. With the following exceptions, it shared the same features as the Model 175: The top was made of fine-grade, violin spruce. The top, back, and even the peghead were bound in a five-ply binding consisting of a white/black/gold/black/white pattern. On these models, even the cone and spider bridge were an anodized gold color. As of this writing only three of these models are known to exist, and those are all roundneck guitars.
Note: All these walnut model guitars known to exist today are of the California thin-body type construction with sawn peghead slots. This would mean that production of these guitars ceased prior to 1934. Some examples have appeared with serial numbers in the 7000 series, perhaps leftovers that were serialized a number of years after they were actually built.
General notes on all the foregoing instruments: These models would seem to fit the category of California-built guitars, since none have been reported without the sawn peghead slots which were unique to early, California-built guitars. You'll recall that this unique saw was used by the Dobro® Corporation only up until the consolidation with National in 1935, at which time it was misplaced or otherwise taken out of service.
Note: Custom built presentation models were always available for purchase, the above instruments are ones which some form of advertising has been seen except for the Models 125&175.
The following models appear after the licensing of Regal and continue until production ended in 1941, and all feature the deeper body style introduced by Regal.
Model 27
The earliest Model 27 had an unbound stained with perhaps faux wood grain body, the hardware was painted silver and some instruments had painted frets and were available as squareneck instruments only. These guitars are extremely rare, as this model evolved into the guitar described below.
The Model 27 was constructed of non-descript hardwood laminate (generally birch or ash). The top of the guitar was finished in Dobros® traditional brown sunburst, with the dark area extending around the outer periphery of the top. The back, sides and neck were finished in a very dark brown, which almost appeared black. The top only was bound in white celluloid, and the fretboards were unbound and most often of rosewood. According to catalogs of the period, this instrument was available in either a roundneck or squareneck version.
The Model 27 was Dobro®'s most popular and (not coincidentally) least expensive of the full size double screenhole guitars. The markup for this instrument was minimum and, in an effort to cut costs, Regal suggested eliminating the three-holes at the end of the fretboard. Dobro® accepted this suggestion, and the Model 27 became the only wooden-body, screen hole, pre-war Dobro not to have this feature.
Late in production (sometime after 1937), Regal-built Model 27's were bound both on the top and the back and even the fretboard was bound. Otherwise, their features match those of earlier Model 27s. In the late 30's this model became the Model 32 as times were getting better and a higher price was called for thus it became the Model 32.
Production of the Model 27 continued through the end of company operations in 1941 although the Model number had changed to a 32.
Model 37
The Model 37 had a three-ply mahogany body as well as a mahogany neck. The body was bound, top and back, with white celluloid binding, as was the fretboard. This instrument was finished in a dark, two-tone sunburst finish. Many of these guitars had a fake mahogany grain applied and careful examination is required to distinguish this from real mahogany. (They were very good at this fake grain procedure.) This model was discontinued by Regal in 1939.
Model 45
The back and sides of the Model 45, as well as the neck, were made of mahogany, while the top was made of select, three-ply spruce. The back, sides, and neck were finished in the customary, two-tone sunburst, with the familiar zipper center stripe on the back. The top was left in a natural, spruce finish. The top and back were bound in three-ply, white/black/white binding, and the fretboard was made of ebony or ebonized wood.
Production of the Model 45 continued through the end of company operations in 1941.
NOTE:
This particular model existed at various times in various configurations. It was first introduced as a dark, unbound student model (identical to the Model 55 except with an unbound neck), which in 1932 became the Model 36. At that time, the Model 45 became a bound, single-screen Cyclops. In 1933, it was re-introduced in its final (and best known) configuration, which is described above.
NOTE:
Of particular interest is the effect that the Great Depression of the 30's had on the prices of the instruments. When production started in the late 20's the Model 45 of the time was the lowest price Model that Dobro had to offer while at the end of Regal's production in 1941, the Model 45 was the most expensive guitar they offered. ( The system used during this entire production era was the Model number also was the price of the instrument ).
These last three models were all available as 14-fret guitars as well as the standard, 12-fret versions. What must be understood about 14-fret guitars is that, until Martin built the first 14-fret models, these were unknown in the guitar world. Then, after they were introduced, other builders followed suit.
As stated previously, the Dopyeras claimed that all 14-fret instruments were built by Regal. The appearance of 14-fret instruments that can be traced to the McKinley Avenue plant, however, proves otherwise.
There are distinct differences between the 14-fret instruments produced by Regal and National-Dobro®. The Instruments produced in California have the same body shape as their 12-fret counterparts. The only difference is that the body is two frets shorter. Regal produced 14-fret guitars, on the other hand, had a very large lower bout, a pinched waist, and an upper bout that was very narrow compared to the 12-fret instruments which Regal built. With the Hawaiian craze that was sweeping the country at this time you would think that more squareneck than roundneck instruments would have been built. In fact, just the opposite is true. A Spanish-style guitar could be converted and played as a slide guitar by the simple installation of a metal nut extension, so many more roundneck instruments were produced than were squarenecks. Today, most players want a squareneck instrument and for that reason vintage squarenecks, which were produced in relatively limited numbers, typically command a higher price than comparable roundneck guitars.
Following is information on some very unique instruments that have surfaced since the late 1960's.
California-built Model 27's
Even though the advertisements for California-era instruments state the Model 27 was available in a squareneck version, only one squareneck Model 27 fitting the advertised description has surfaced.
In 1966, Tut Taylor, who at the time was heavily involved in the vintage instrument trade, found an instrument that defied all printed advertisements. This instrument looked like a Model 27 but the colors weren't as specified in early advertisements. The body dimensions matched those of the other California-built guitars of the time, but this was a squareneck and the coloration was different. All Tut knew was that it was the best sounding guitar he had ever found and it became the standard from which he produced his famed Tennessee line of resonator guitars.
The front of this instrument had a double sunburst with the dark shading filling in the area between the screen hole and the coverplate. The back of the guitar had a sunburst in the shape of a teardrop, and there were sunbursts on the peghead as well as the back of its neck. The heel of the neck on this guitar is full-width, indicating it was California-built. The slots on the peghead were unusually long and the bottom half of the logo was actually situated between the slots. The neck has since been seen on National instruments of the period (Remember the swapping of parts?) and this guitar has been traced back to the McKinley Avenue plant in Los Angeles.
So, in effect, what we have here is a Model 27 that is not described in any known literature. This particular color pattern has shown up on 14-fret roundneck and squareneck instruments, but not on any 12-fret roundnecks as of this writing (March, 2005). Since Tut's initial discovery, twenty more of these instruments have surfaced, bringing the total number of known instruments to twenty-one, Due to their unique nature, builder/historian Bobby Wolfe maintains an up-to-date list of these instruments.
Model 37w/Flamed-Maple Back
These instruments, which have only shown up in the last 15-20 years, are yet another unique variation of the standard Model 37. These guitars have all the characteristics of the normal Model 37s except that, instead of Mahogany, the backs of these instruments are made of Flamed Maple, while the front and sides are constructed of non-descript woods.
So far, only squareneck versions of this guitar have been uncovered, all with the full-width heel indicative of a California-built guitar. The shading on most of these guitars is reddish, rather than the more common brownish-orange. The back of the guitar had a sunburst in the shape of a teardrop, and there were sunbursts on the peghead as well as the back of its neck. The body is bound, top and back, in white celluloid, as is the rosewood fingerboard. So far, only squareneck versions of this instrument have been uncovered and, once again, all can be traced back to the McKinley Avenue plant in Los Angeles. The necks on these guitars are identical to the necks of the Model 27 guitars described in the preceding paragraphs.
At the present time, only nine of these instruments are known, and three of those have a tan sunburst rather than the reddish finish previously described.
Model 45 w/Flamed-Maple Back
By now, it should come as no surprise that some model 45s have also surfaced featuring the same flamed-maple back and red shading described above. The variation from the standard model 45 is in the use of the flamed-maple for the back and the now familiar reddish shading with the teardrop-shaped sunburst on the back and, once again, the use of the National-style neck with a sunburst on the front of the peghead and the back of the neck. This particular version has only been seen as a squareneck and at the present time only three such instruments are known.
PRE-WAR SERIAL NUMBERS
Again as with most information in the Pre-War period there seems to be no hard and set rules as to assignment of serial numbers to Dobro® brand guitars, either at Dobro® Corp. & Dobro®-National or at Regal. No serial number records were kept as were at other companies such as Gibson, Martin or even National. Serial numbers when used were found on the end of the peghead.
With Dobro® and Regal the placement of a particular serial number into a time period of manufacture is a function of using old catalog cuts to place the availability of a certain instrument into a time period and then checking serial numbers on these instruments as they are found. Needless to say this seems like a back door policy, however, considering all the other variables with these companies it is not unexpected. Many other individuals who have done much of the detective work required have made the task easier and the following information is probably as accurate as any available.
Year Serial Number
1929--------------------------------------- 800---1,400's
1930--------------------------------------- 1,400---2,000's
1931--------------------------------------- 2,000---2,600's
1932--------------------------------------- 2,600---3,200's
1933--------------------------------------- 3,200---3,900's *1
1933---------------------------------------.4,000---4,900's *2
1933--------------------------------------- 5,000---5,600's *3
1934 - 1936------------------------------ 5,700---7,600's *4
1936 - 1937-------------------------------8,000---9,000's *5
*1. 3,200's-3,900's
This series of numbers was used immediately prior to the licensing agreement with Regal and during this period business was hectic.
*2. 4,000's This entire set of numbers had been set aside for Regal, however don't be surprised to see a California built guitar show up with a number in the 4,000 series.
*3. 5,000's---5,600's Because of the setting aside the 4,000 series of numbers for Regal some instruments built in California in 1933 will be found with these numbers on them.
*4 5,700's---7,600's Guitars were going out the doors during this period like a wildfire burning on the prairie, as can be seen by the numbers almost 2,000 serialized numbers in a two year period.
*5. 8,000's---9,000's This was the beginning of the end for California built wood bodied Dobros, with very few 9,000 series guitars seen today.
So there you have the serial number history of Pre-War Dobro® and Regal woodbodied resophonic guitars. Just as with other manufactures there is a period when (for whatever reason) the better sounding instruments were more consistently produced. The period for California built guitars seems to be in the 7,000---8,000 series of instruments. With Regal, due to their inconsistency with serial number usage, there is no way to put a better era on these guitars, let us just say that there were many fine sounding instruments produced by Regal that are as good as any California built guitars.
The following special classifications were used randomly by both Dobro® and Regal, and have been placed in a particular time period due to information from various sources.
L-9000 series- used mainly by Regal in the period immediately following assignment of all Production to them in August of 1937.
A-Prefix Used by Regal in 1936.
B-Prefix or Suffix used primarily by Dobro® during 1932-1933 on Cyclops models.
M-Suffix not widely used but may be found on guitars manufactured in the Mid 30's.
2-Suffix designated a factory second.
FS-Prefix designated a factory second.
National resonator guitar serial numbers

Guitar Serial Number Dating

Richard, the coding seems to be a bit different from what I've read Dobro (OMI) used in the 1970s, but the 'M' means a metal body, the '6' is 1976, and the 498 indicates its serial number ranking. Vni font for windows 10. This message was edited by Russ Young on 25 June 2005 at 11:00 PM. Slash it 2 crack. There are no serial numbers on the top of the head stock. Which is why I had a really tough time finding out any history behind the guitar, the only numbers are the patent pending numbers and they led me on a wild goose chase.





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