MY DATA, INFO AND MODIFICATIONS FOR THE BEST USE A HARMONY WOOD FLOATING BRIDGE ON HARMONY SOLID BODY ELECTRIC GUITARS WITH VIBRATOS:

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SHOWING THAT HARMONY ST1478 AND H19 BRIDGES HISTORY AND OPTIONS ARE NOT WRONG PARTS BUT JUST EARLY AND LESS TECHNICAL GUITAR HARDWARE ALIGNMENT DESIGN:


FRANCOIS' ST1478 PAGE:

EXAMPLES:

WITH STANDARD BRIDGE;  EARLY THRU MID 1960'S; FACTORY INTONATION DATUM SET TOO SHORT (Intonation sharp):

WITH STANDARD BRIDGE;  CORRECT REARWARD INTONATION DATUM:
(Bridge must be glued, pinned, V slotted at intonation angle and graphite lubed for proper vibrato action use; Otherwise bridge base will slip lattitudinally and longitudinally on pickguard with aggresive vibrato use).

WITH ROLLER BRIDGE I'M TRYING TO MAKE WORK:
(NOTICE STRING SPAN AT UPPER NECK IS TOO WIDE HERE TOO):

CONFIRMING SAME BRIDGE MOUNT:

WITH RED P'UP BOBKAT'S ROLLER BRIDGE:

WITH AFTERMARKET WOOD FIXED COMPENATION FLOATING BRIDGE:

WITH STANDARD BRIDGE - GOOD PIC OF UPPER NECK STRING SPAN STILL MARGINAL:
(But a blank same-replacement bridge would offer ability to recut string slots span / spacing closer):



FRANCOIS' HARMONY H19 PAGE;

EXAMPLES:

FIXED METAL FLOATING BRIDGE SOLUTION;  STILL WIDE STRING SPAN ALONG UPPER NECK:

REQUIRES LES PAUL TYPE BRIDGE STUDS DRILLING AND INSTALLATION;  ALTHOUGH THESE HARMONY BRIDGES ARE NIGH IMPOSSIBLE TO FIND EXACT REPLACEMENTS, AND STRING SPAN FOR UPPER NECK STILL PROBLEMATIC WITH STANDARD STRING SPAN BRIDGES; WOULD REQUIRE FINDING A SIMILAR REPLACEMENT WITH NARROWER STRING SPACING OR RAW SADDLES TO CUT NARROWER SPACED STRING SLOTS UPON:

SEE TIGHT UPPER NECK SPAN 1:

SEE TIGHT UPPER NECK SPAN 2:

SEE TIGHT UPPER NECK SPAN 3:

SEE TIGHT UPPER NECK SPAN 4:

SEE TIGHT UPPER NECK SPAN 5:

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These webpages are under ongoing construction.
1965 Silvertone Harmony model S1478
With Original Fibreboard Case
~ Page 33;  8 Jan, 2009;  Researching Optimum Bridge Data ~
EXISTING / ORIGINAL BRIDGE DATA:
(In decimal inches; Probably equivelant to Japanese / metric specs)
IDEAL MAXIMUM STRING SPACING & SPAN SHOULD BE:
Baseplate mounting studs span
2.740"
Strings span
1.950"
String spacing
.390"
.153"
Baseplate studs diameter
2.740"
1.875" = 1 7/8"
.375" =
3/8"
.153"
IDEAL MINIMUM STRING SPACING / SPAN  SHOULD BE:
2.740"
1.575" = 1 9/16"
.315" =
5/16"
.153"
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Initial info and data for neck / string spacing / bridge strings span:

The string spacing / span of this guitar's bridge puts strings 1 and 6 at the edge of the frets at the high end of the fretboard.   This makes a full spectrum of modern playing techniques a bit awkward.  So I suggest some modifications to make this guitar's bridge or another bridge and / or plate compatible with this guitar and provide a better / narrower string spacing / span at the bridge and thus along the upper frets of the fretboard.

There is nothing at all wrong with this guitar's bridge and it's string spacing / span not fitting well to the guitar's upper neck width, .....but quite the opposite;  It's the narrow upper neck design that doesn't match up well with common bridge string spacings of outside supplier bridges Harmony had to choose from when they realized how aggressive vibrato would become and that the non-intoneable wood bridge they originally designed onto the guitar was not well suited for such vibrato use.  But even their wood bridges also brought the upper-fretboard string span to the outer edges of those frets.

The best guess I can make about why Harmony would not be more concerned about string spacing at the upper fretboard, is that general public Players playing techniques were not as advanced and aggresive as they became.  Harmony's original non-intoneable wooden bridge used on the original design of this guitar, did not work very well at all for vibrato use, and it's string spacing / span was also too wide for the narrower design of the upper neck.  The original design bridge would wobble and otherwise displace itself with vibrato use, so Harmony wanted a bridge that would work better with the vibrato.  I feel rather certain that Harmony acquired the intoneable roller bridges for their last runs of Bobkat and Sihouette guitars, from already existing Japanese parts sources, rather than tooling-up to make a wider neck or narrower bridge;  And Harmony likely felt that a slightly wider upper fretboard spacing was an acceptable trade-off for an already existing replacement bridge that would work better with the vibrato.  I also think it indicative that this guitar was made just before the period that Harmony started jobbing (contracting) the manufacture and branding of their guitars to Japan, slightly ahead of Epiphone doing the same;  So Harmony probably saw their economic demise at hand when they decided to use these Japanese bridges on the last of their USA made guitars.

I recommend Maximum and Minimum string spacings / spans listed below that will allow for more playing tecniques.  HOWEVER, there are some problems in seeking that string spacing / span with current common replacement bridges:

Most modern bridge makers base their geometry upon the wider bridge geometries of Gibson and / or Fender bridges;  So the string spacing / spans of common replacement hardware do no better in matching the narrow neck of Harmony guitars of this guitar's period.  Where narrower string spacing / span can be found on a replacement bridge and still be similar to this guitar's bridge, then their mounting plate & posts geometry is most likely to be different than the measurements of this guitar's bridge mounting plate / posts;

So modifying the upper bridge assembly mounting holes, or the body mounting plate or it's posts would more likely be required than finding all the geometry to match up with this guitar's mounting plate / posts.

I am still in the process of searching the data of suppliers of bridge and bridge parts, to be able to make the best suggestions for getting a narrower string spacing / span onto this guitar's bridge.

Data is being compiled and drafted on this page to provide for both my search and for future searching should I not be able to find a proper solution in a reasonable amount of time.


Collecting data of bridge manufacturers for seach and comparitive data:

Measurements less than .010" become skewed in suppliers conversions to inch fractions and metric system;  So must be checked for proper and / or modifiable fit.

Common GIBSON bridge data:

Les Pauls:
Bridge string span is 2 1/16" = 2.063".
String spacing at the bridge saddles is .413" = 13/32" , which is 1/32" shy of 7/16".  String spacing in the effective picking area is approx 3/8". 

SG:
Bridge string span is 2";  .400" string spacing, which also equates to 13/32" at bridge and 3/8" in picking area.

Gibson tuneamatic bridge posts are .145" dia.

Post span is 2.907".  2.900  is common on replacement bridges for Gibson.

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FENDER data is being compiled;  Particularly looking at Mustang and Jazzmaster / Jaguar bridge geometry compatibility.

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BIGSBY Rocker Bridge minimum string span slot cutting area is 2.0", which is wider than this guitar's existing bridge string span.

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SHOWING THAT HARMONY ST1478 AND H19 BRIDGES HISTORY AND OPTIONS ARE NOT WRONG PARTS BUT JUST EARLY AND LESS TECHNICAL GUITAR HARDWARE ALIGNMENT DESIGN:


FRANCOIS' ST1478 PAGE:

EXAMPLES:

WITH STANDARD BRIDGE;  EARLY THRU MID 1960'S; FACTORY INTONATION DATUM SET TOO SHORT (Intonation sharp):

WITH STANDARD BRIDGE;  CORRECT REARWARD INTONATION DATUM:
(Bridge must be glued, pinned, V slotted at intonation angle and graphite lubed for proper vibrato action use; Otherwise bridge base will slip lattitudinally and longitudinally on pickguard with aggresive vibrato use).

WITH ROLLER BRIDGE I'M TRYING TO MAKE WORK:
(NOTICE STRING SPAN AT UPPER NECK IS TOO WIDE HERE TOO):

CONFIRMING SAME BRIDGE MOUNT:

WITH RED P'UP BOBKAT'S ROLLER BRIDGE:

WITH AFTERMARKET WOOD FIXED COMPENATION FLOATING BRIDGE:

WITH STANDARD BRIDGE - GOOD PIC OF UPPER NECK STRING SPAN STILL MARGINAL:
(But a blank same-replacement bridge would offer ability to recut string slots span / spacing closer):



FRANCOIS' HARMONY H19 PAGE;

EXAMPLES:

FIXED METAL FLOATING BRIDGE SOLUTION;  STILL WIDE STRING SPAN ALONG UPPER NECK:

REQUIRES LES PAUL TYPE BRIDGE STUDS DRILLING AND INSTALLATION;  ALTHOUGH THESE HARMONY BRIDGES ARE NIGH IMPOSSIBLE TO FIND EXACT REPLACEMENTS, AND STRING SPAN FOR UPPER NECK STILL PROBLEMATIC WITH STANDARD STRING SPAN BRIDGES; WOULD REQUIRE FINDING A SIMILAR REPLACEMENT WITH NARROWER STRING SPACING OR RAW SADDLES TO CUT NARROWER SPACED STRING SLOTS UPON:

SEE TIGHT UPPER NECK SPAN 1:

SEE TIGHT UPPER NECK SPAN 2:

SEE TIGHT UPPER NECK SPAN 3:

SEE TIGHT UPPER NECK SPAN 4:

SEE TIGHT UPPER NECK SPAN 5:

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UPDATE 10 Jan. 2009:

~ OPS CHECKS FINDINGS ~

After registering and installing the bridge, tuning the guitar back up, and playing it for about an hour;  I was quite amazed that the wide string span at the upper neck did not interfere with finesse hardly any at all !  At first it feels peculiar because the 1st and 6th strings are so close to the edge of the fretboard;  But it didn't interfere with technique finesse in about an hour's playing at all.  It takes about 20 - 30 minutes for the hand / finger / brain motor coordination to get the feel of any guitar anyway, even when switching between different guitars geometry in a working act;  So I suppose getting used to a slightly different feel of string span for a narrow neck isn't "any" different;  And I was equally surprised that the guitar played well with the strings right at the end of the frets;  Certainly not the best setup by technical standards, but surprisingly unobtrusive.

Then I wondered how peculiar moving all strings but the 6th string bassward one notch in the saddles, ....making the string spacing between the 5th and 6th strings tighter than the other 5 strings;  And again I was quite surprised that it wasn't obtrusive either !  It again felt a bit peculiar at firts, mainly because I was aware of the different string spacing, but in only a very short amount of playing time it became un-noticeable.  Of course "squeezing" the spacing between the 5th and 6th strings at the bridge becomes less and less towards the neck nut, half the "squeeze" at the 12th fret, ....and I suppose the upper frets being a tight fingering anyway made the "squeeze" much less noticeable than anticipated.

However;  Even though I find the string spacing / span at the bridge nowhere as obtrusive as I thought it would be;  I still think the guitar would feel and play better if the string spacing / span at the bridge were reduced to the specs shown further above on this page.  So I am still providing the bridge stings spacing / span data in the event a slightly smaller string spacing / span might be desired for this ST1478's narrow upper neck.
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MY DATA, INFO AND MODIFICATIONS FOR THE BEST USE A HARMONY WOOD FLOATING BRIDGE ON HARMONY SOLID BODY ELECTRIC GUITARS WITH VIBRATOS:

Ignore "next page" links on each page and use this list of links for best continuity of process:
X
X
X
X
X
X
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