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Dating Kay Guitars Kay instruments are tricky with no understandable serial number system, questionable reliability on finding stamps, an...

Identifying and Dating Kay Guitars

Dating Kay Guitars

Kay instruments are tricky with no understandable serial number system, questionable reliability on finding stamps, and model numbers that change or are reused.
This is my best attempt at pooling information together to help people identify their instruments

I cite my information as best as I can but there are points that are common knowledge among the Kay community or are observations and conclusions that I have reached from my work.
Pictures are mine unless otherwise cited.

If you are unable to identify your instrument, feel free to Contact Me and I will do my best

Branding

Its a safe bet to say that a decent chunk of Kay-built instruments do not say Kay anywhere on them which has led to decades of confusion which I hope to untangle. 

A significant portion of Kay's business was producing and selling instruments to retailers who would then sell them as their own house brand of instruments. There are a variety of names that Kay guitars appeared under from Airline to Marathon to Silvertone to Windsor! And yet there are plenty of Kay guitars that have no brand name on them.

Kay came to be in 1931 after being renamed from Stromberg-Voisinet. They hit their peak production in the early 1960s and were dissolved by the end of the decade. Anything post-1969 is not an American-made Kay guitar and this information will not help you.


Company History

1890
  • The Andrew Groehsl Company was formed in Chicago and began production of guitars, mandolins, and traditional European instruments
1921
  • Groehsl is bought out by Henry "Kay" Kuhrmeyer, Frank C. Voisinet, and Charles G. Stromberg and thus forms Stromberg-Voisinet. [7]
1931
  • June, Kay Kraft line is announced to be shown at the S-V booth at NAMM [9]
  • July 1st, The Kay Musical Instrument Company is formed [8]
1938 [9]
  • 62 employees were involved in the production of instruments
  • Instruments were sold through 40 wholesalers in 15 states on top of  mail order
  • The total sales of the company amounted to around $250,000
  • 60 percent of all finished instruments were sold outside of Illinois


Headstock Shapes and Logos

Michael Wright has compiled one of the largest picture galleries of headstock photos in his book "Guitar Stories Vol. 2: The Histories of Cool Guitars". I own the book and have found it to be an invaluable resource in identifying these old guitars. You can buy the book here on Amazon and I would highly recommend it. 

Here is an excerpt from his book. 

Quintessential Kay shape
[1941-1968]


Image Credit: VintAxe
Flat Martin-esque
[?-1941]
'y' underlined logo
[?-1939]
Image Credit: Reverb - BirdHouseMusic
Large 3-point
[1948-1958]
Gibson-esque "open book"
[1938-1944]


Harmony-esque 'rounded'
[1938-1947]
Three-line 'a' logo
[1940s]
3 point rounded
[1940s-1965]
Metal cursive logo
[1948-1966]


Narrow 
[1966-1968]






















Vanguard
[?-1967-?]




'Cleaver'
[1965-1968]





'T' logo 
[1961-1965]

Wider 'single point' headstock
[1968-1970]

'Spade' with 'plectrum' logo
[1966-1968]


Stamps

Kay instruments had a variety of ink stamps, most of which have meanings that have long since been lost. You can find the stamps on the inside of the back of the instrument which is usually visible with a flashlight via the f-holes or sound hole. It is a consensus of the Kay community that Kay instruments do not have a serial number system and that most of the stamps are likely related to the batch of instruments that it came from. It is also not unusual for a Kay guitar to not have any stamps or markings at all 

It is certainly possible that the workers at Kay knew how to interpret these stamps and maybe even track down a date in case of a quality control issue. Any such knowledge has been lost and never surfaced. Coincidences where the stamps appear to refer to the year have happened but they are infrequent enough to just be happenstance.
  • "L#### ####" or "L####"
    • The "lot" number of the instrument which refers to which batch of instruments it came from
    • It does not contain any information about the year that the instrument was made.
    • Rarely, the second set of numbers is the model number but I've only seen it on the K-6100 and K-6000 models
    L590 6889 in a K-6970 Swingmaster
    L4229 6100 in a K-6100 Western Dreadnought
    I've only ever seen the numbers match on the K-6000 and K-6100 models
  • "K-#### ####"
    • Numbers immediately following the "K" are the model number of the instrument
    • Any additional numbers have no known meaning and are presumed to be a batch number

    K68 is the model number of this mandolin
    468 is a batch number
  • "N#", "P#", "B#"
    • No known meaning
    • Commonly (and incorrectly) attributed to be a model number 
    • N numbers can go up to 15. [3]
    • P numbers can go up to 7. [2]
    • B numbers can go up to 10. [4]
    • N and P numbers can occur together
    • B and N numbers can occur together
P4
P4 stamp

N-2 stamp


    • "DEC ####"
      • Only appears on some instruments built in the 1930s and 1940s
      • "DEC" would logically refer to December but I have not found any stamps referencing any other month so I'm unsure
      • "####" or "##" refers to the year the instrument was built
    "DEC 1938" with what looks like a "2" written after it

    "DEC 1941" 
    (the year is stamped upside down)

    "???? 45"
    • "SECOND"
      • Appears on instruments from the 60s with obvious blemishes such as a knot in the wood (as was the case with this instrument)
    Image Credit: Ebay

    • "K##" stamped on the back of the headstock 
      • Only appears on instruments built in the 1930s and very early 40s.
      • "##" refers to the model number of the instrument.

    Tuning Machines

    Kay guitars used tuning machines from a few suppliers during their lifetime. Waverly tuners are able to be dated within decade ranges while Kluson tuners can typically be dated more exactly and are the best method of putting a year behind your guitar. I've attached an external resource which I frequently use and two articles that I have written about these tuning machines below.
    • Waverly
      • "Square" and "Small Bell" end plates used in the 1930s and into the 40s
      • "Bell" end plates used intermittently on student level instruments in the late-50s and 60s
    • Kluson
      • Appeared as early as the late-1930s and continued until Kay's demise
      • Often removed, sold separately, and replaced with cheap tuners 
      • Unique "scalloped" plate end design is easily identifiable
      • Appears on most instruments prior to the 1960s 
      • Remains on mid and higher tier instruments 
    • Misc Japanese
      • Took over on student model instruments in the 1960s
    Identifying Kluson closed-back (1947-1969) tuners: http://www.guitarhq.com/kluson.html
    Identifying Kluson open-back tuners (1930s-1947): https://www.stlamateurluthier.com/2019/08/guide-to-kluson-open-back-tuners.html

    Kluson tuners are currently being produced by WDMusic and their reproductions can be pretty close to the originals. The best method of confirming originality is to look at the washers on the ends of the tuner shaft. Original, vintage tuners will have metal washers while reissues will have nylon washers

    Nylon tuner washers indicating reissue tuners placed on a '60s Kay

    Bodies

    Kay guitars have a reputation for using laminated woods (as opposed to Harmony's reputation for solid wood) and their instruments were advertised in catalogs as "crack proof". However, this is not a strict rule and finding a Kay built with some solid wood is not nearly as uncommon as people think.

    You can identify a solid or laminated top by checking any unbound edges to see if the wood grain is consistent or by using a mirror and a flashlight to do spot checks on the grain from the outside and inside of the instrument. If an instrument has cracks in the wood that run with the grain then that piece of wood is solid. 
    • Spruce tops
      • Solid tops are prevalent on flat top guitars until the 1960s when it becomes hit or miss
      • Pre-1960s archtops are likely to have solid tops
      • Thinline/hollowbody instruments have laminated tops
      • Most, 50s-60s, student model instruments have laminated tops
    • Birch tops
      • Appear on student grade instruments like archtops and flat tops
      • Often laminated
    • Mahogany back and sides
      • Laminated more often than not
    • Maple back and sides
      • Highly figured pieces are often laminated
      • Solid sides and back do exist but they are typically not as figured
    • Birch back and sides
      • Often laminated
    • Brazilian Rosewood
      • I do not know whether the Kay Kraft Model C has solid or laminate
      • The K-6000, most famously used by Elmore James, has laminate back and sides
    Solid body instruments are typically constructed of multiple pieces of poplar and can feature a maple veneer on the front and the back.

    Carved vs Pressed

    Carved top instruments have their tops built from a large solid block of spruce and are shaped to the desired profile. Pressed tops are either solid or laminated wood of a final thickness and pressed to their shape via heated molds. Carving a top is much more labor and time intensive than pressing so carved tops are typically reserved for the high end instruments and are less common than a pressed top.

    These are fairly uncommon but some of the high end models from the 30s and 40s may have them
    • Carved tops disappear entirely by the mid 1950s.

    Necks 

    Kay necks were 'guaranteed' against warping by the inclusion of steel rods (some adjustable) in the neck. The name "Speed Demon" originated from the name of the neck profile on some of the 50s guitars but was later applied to the K57x line of instruments [5]. 
    • Poplar is the most common wood used for Kay necks
      • Often finished in a brown lacquer to mimic mahogany
    • Maple 
      • Plain maple can be seen on some pre-1960 mid tier instruments
      • Figured maple can be seen in multi-piece necks on high end instruments
    • Mahogany 
      • Appeared as late as the 1950s on high end instruments
      • Much less common than the previous woods

    Fretboard

    Wood analysis comes from personal experience and www.wood-database.com's article on identifying Brazilian
    • Brazilian Rosewood
      • Standard for most instruments up until the 1960s 
      • Started becoming reserved for only the high-end models
      • Tight, closed grain
      • Will not fluoresce under a blacklight when dissolved in water [1]
      • Very sweet smelling when sanded
      • Reddish brown to jet black color (some cheap cuts can be pretty light colored) 
    • Indian Rosewood
      • Picked up in the 1960s as a budget alternative to Brazilian
      • Open grain. Twice the pores per square inch as Brazilian [1]
      • Dark brown or purplish brown color
    • Maple
      • Painted black, brown, or chemically ebonized
        • Chemically ebonized boards appear in the 1930s on instruments such as the Kay Kraft line
      • Can also be left natural with lacquer or dyed red
    • Walnut
      • Used in the 1940s and sometimes lacquered over

    Position markers

    Pre-1950s position markers are often true pearl while later ones are often celluloid. I've seen true pearl on a 1966-68 flat top and have seen celluloid on a 40s archtop so it isn't a solid rule.
    • Dots
      • 3/8" pearloid or white dots in a single line pattern appeared in the 1960s
      • 7/32" mother of pearl dots at latest in the 1950s
      • 3/16" white dots in an alternating 1 and 2 dot pattern were common prior to 1960
      • Pick shaped inlays
        • Appeared on mid to late 60s guitars
        • Some painted inlays can be found like the K1160 "music note" guitar.

          Frets

          • Composition
            • Standard nickel frets are the most common
            • Brass frets appeared in the 1950s and continued until the company's demise. 
              • Typically reserved for lower end instruments
          • Zero-Fret
            • Zero frets only appear on Kay guitars made after 1968
            • 1968-1970 - Valco-designed instruments
            • Post-1970 - Japanese-import instruments that use the Kay name
          • Size
            • Thin, short frets were common before and during WWII
            • Later guitars either had a standard size or a jumbo size which was wider
            • I cover a variety of exact fretwire dimensions on my article Vintage Fretwire Dimensions

          Truss Rods and Neck Reinforcements

          Kay guitars did not advertise neck reinforcements until the 1950s and from experience I have found that most instruments built before then relied solely on the strength of the wood. Kay used either a non-adjustable neck reinforcement or a true truss rod, never both.

          Neck Reinforcements

          • Pre-1940s - None
          • 1950s-1959 - U-shaped steel bar, open-end facing downwards
          • 1960s - Rectangular steel bar

          Truss Rods

          • "Thin Lite" which was introduced in the early 60s and is most similar to a Gibson style rod. Appears on mid-tier instruments.
            • The design is a long carriage bolt between two half-moon washers. It is held in place by the square hole in one washer.
            •  These often become dislodged and are rendered inoperable but they can often be "repaired" by pulling the truss rod (by the nut) away from the body perpendicular to the strings and slowly turning until the end of the rod locks back into the washer.
          Kay truss rod illustrating the design and the flaw that plagues them
          • "Kantilever" or "Balanced Tension" which was introduced in the 1950s and is adjustable at the heel of the instrument. Appears on higher end instruments like the Thin Twin and some of the fancier archtops
            • These are terrible and don't work well at all
          Image Credit: 1959 Catalog

          Neck Joints

          The Zorzi adjustable neck joint was invented by Joseph Zorzi who was hired at Stromberg-Voisenet in either 1926 or 1927 [6]. It first appeared in 1932 with the line of Kay Kraft instruments that it is best associated with. But you can also find them on other 30s lines like the Kay Deluxe. It was intended to prevent against costly neck reset operations by allowing the user to easily adjust the angle of the neck to the body.

          The Zorzi neck joint disappeared, along with the Kay Kraft line, at the end of the 1930s.
          'Zorzi' adjustable neck joint on a 1930s Kay Deluxe
          The joint featured a radiused, dyed wood block with a raised center rail that was secured to the body of the instrument with three small nails. The neck was carved to mate with the block and had a groove which could slide along the rail. A bolt protruding from the neck fits through a hole drilled in the neck block and is secured with a wing nut. That bolt is held in place by a wood screw driven through the heel of the instrument.

          Instruction Sticker
          Image Credit: Facebook - Thom R
          The mounting hardware that appears on the Zorzi neck

          Dovetail

          The most common and traditional neck joint for guitars and stringed instruments. Kay cut big, sloppy dovetails and relied on the glue to hold them in place which is why tons of Kay instruments have necks pulling away from the body

          Bolt On

          1961 was a transitional year for Kay when instruments started switching from dovetails to a 3 bolt system. It is prominent in electric hollow-body instruments and student model acoustics. The nicer acoustics typically kept their dovetail joints.
          1960s 3 screw neck joint

          1968 saw the introduction of a micro-tilt adjustment in the new Valco-designed instruments.

          3 screw neck with microtilt

          Bridges

          Pyramid bridges appeared on some instruments in the 1930s through the 1940s. Bridges from this era also have two pearl dots hiding bolts that mount the bridge to the top.

          Brass decorative carriage bolts are a staple of Kay flat top bridges from the late 1940s until the end of the 1960s. They typically have brass nuts which are tightened from underneath to secure the bridge to the guitar top.
          Kay bridge bolts
          Flat top bridges can either be pinned or pinless and generally look similar to the picture below. Some Kay jumbo guitars have an adjustable saddle built into the bridge and a third decorative bolt

          1960s flat top bridge
          Standard on most all Kay flat tops

          1940s archtop bridge
          (with added B string compensation)
          1960s hollow body bridge


          Labels

          Early Kay builds featured foil labels which were adhered to the back of the instrument and are visible through either the soundhole or the bass f-hole. These often fall off and are lost but can be very helpful when they are still intact.

          Light Blue/Silver Label (1930s)

          "Manufactured by Kay Musical Instrument Co Chicago"

          Dark Blue/Red Label (1940s)

          "Worlds Largest Manufacturers of String Instruments"
          "Kay Musical Instrument Co"
          "Chicago Established 1890"


          Pickups

          Kay guitars did not use Gibson or DeArmond pickups like people on the internet often claim. The design and materials of Kay pickups are unique compared to original pickups from both of those manufacturers and so I believe it is more likely that Kay wound them in-house using their own employees.

          I've put together a guide of all the Kay electric pickups I've found and the date ranges that they appear.

          $$$ Value $$$

          The big question everybody asks is "How much is my Kay guitar worth?" and that is a fantastic question! It depends heavily on condition and playability since every Kay guitar is at least 50 years old and needs a good amount of work to get it back into playable shape.
          The value of your instrument is directly related to the amount of work it needs. 

          I often see people selling their Kay instruments for $300 as "wall hangers" or "slide guitars" which is a nice thought but ultimately like selling a wrecked automobile for $10,000 as a "lawn ornament".
          People won't pay top market value for a project instrument.

          Reverb.com is one of the greatest resources for finding what your guitar really sells for, I would highly recommend checking there and clicking the "Show Sold Listings" checkbox in the filter. Find out what your instrument actually sells for, subtract the cost of repairs, and you should land around a fair price for your instrument.

          Feel free to Contact Me and I can provide information about your guitar's model and age

          Common Issues 

          DIY repairs are the quickest way to damage and devalue an instrument
          Always consult with a reputable luthier (not a guitar tech) before performing any work
          Never ever use super glue, epoxy, gorilla glue, or Titebond III
          Guitars that are 'repaired' with these are often beyond saving
          • There are cracks in the wood
            • This occurs when an instrument is exposed to a climate different than the ideal (70 degrees Fahrenheit and 45-50% humidity) and the wood has shrunk
            • Do not try to fill the cracks with glue or put clamps on the guitar to press it together
            • Your guitar needs proper humidity and cleats
          • The neck heel is pulling away from the body
            • Do not shove glue in there, you won't do anything except make a later repair harder
            • Some folks put a screw through the heel to hold it in place. I don't like that method but oh well
            • Your guitar needs a neck reset or a proper bolt-on conversion
          • The frets have large divots in them
            • Frets are like tires on your car, they need replacing every so often
            • Your guitar needs a refret
          • The strings are buzzy or the neck is bowed
            • Most Kay guitars lack adjustable truss rods and so forward bow cannot be easily repaired.
            • Your guitar needs a fretboard planing and refret or more ideally a truss rod installation
          • The strings are too high off the fretboard
            • As string tension and climate shift the wood in a guitar, they inevitably need the neck to be steamed off and a new angle carved relative to the body.
            • Some people will recommend shaving down the guitar bridge which is like putting a bandaid on a broken bone and damages the original bridge beyond repair.
            • Your guitar needs a neck reset 
          • The bridge is lifting and coming off
            • Many bridges are glued directly onto the lacquer which causes them to lift and raise the action. 
            • Do not use glue to fill the gaps or drive screws into the bridge to bring it back down. The only fix is to remove the bridge, lightly scrape off any lacquer, sand the bridge bottom to match the contour of the top, and reglue it.
            • Your guitar needs a bridge reglue and often a bridge plate patch
          • There is no sound coming from the electronics
            • This can be a variety of things from dead capacitors, dirty potentiometers, shorted wires, and even dead pickups.
            • Don't replace any vintage components unless you absolutely have to
              • Tone capacitors are often the first to go and replacing them is not unheard of
              • Pots can be cleaned with DeOxit 
            • Your guitar needs an electronics evaluation and cleaning

          Research

          The internet and the incredible effort by members of the community to digitize old catalogs make it quite possible to date instruments made by Kay between the 1950s and 1970s. Anything before 1950 gets a little trickier to date due to the lack of available catalogs

          Once you have used the above information to get an approximation of how old your guitar is, I would recommend checking out these resources to try and narrow down the date of production.

          Catalog Scans

          Model Numbers and Production Dates

          This excerpt is one of the most complete lists of Kay guitar model numbers and production dates from Michael Wright's book "Guitar Stories Vol. 2: The Histories of Cool Guitars". I intend on developing a Kay model database at some point


          Sources

          [7] https://mtr.arcade-museum.com/MTR-1922-74-10/31/
          [8] https://mtr.arcade-museum.com/MTR-1931-90-7/34/
          [9] https://www.nlrb.gov/case/00-R-000474
          [10] https://mtr.arcade-museum.com/MTR-1931-90-6/17/