A look at a fabricated, 6 string, fixed intonation saddle on a Danelectro 1457.
(My #1 personal guitar).
Hand cut fixed compensation brass saddle retrofit.
Original vintage Danelectro bridge plate.
Threaded socket in the bottom of the saddle receives screw from the underside of bridge plate through the original fore-aft adjustment slot in the bridge plate. Saddle adjusts fore and aft in the slot and also rotates horizontally around this screw for latteral horizontal angle adjustment.
has nothing to do with bridge assembly.
At first glance the intonation of the 3rd and 4th strings look quite offset from each other; But a closer look at the horizontal rotation of the saddle and the angles referenced to the strings allows us to see the very slight offset from the saddle's effective centerline:
6 string intonation. The image above is the 6-string fixed saddle cut from brass, with the intonation points ( red dots ) displaced fore and aft from the intonation mean datum ( marked Center "C" ). Notice that strings 4, 5 & 6 are intoned almost the same as strings 1, 2 & 3 ...just set aft a tad bit farther. It's the shift in cycle of 4ths / 5ths realtaionship between adjoining strings, upset in the note step relationship between strings 2 and 3, that offsets the intonation between 1,2,3 and 4, 5, 6; While string 3 is offset a tad longer due to being set for a non-wound string on this guitar. Were all the strings tuned in a cycle of 5ths and follow a linear string gauge chart-slope, then the intonation would be a straight slanted line. The slanted offset from perpendicular to the strings accounts for stretched tuning and Equal Temperment; Otherwise the saddle would be more perpendicular to the strings, offset only for string gauge differences in each's exact scale length.
Non-destructive mounting of intoneable Danelectro reissue bridge.
This option was chosen as the best by far.
Fabricating a new bridge plate to (1) match vintage Danelectro bridge mounting screw geometry and, (2) to receive Danelectro reissue / Gotoh tuneamatic parts and, (3) with string ball-end receiver holes for all 12 strings on back of bridge plate rather than the reissue bridge's 6 through the body plus 6 through the back of the bridge.
Non-destructively fitting an intoneable 12 string bridge onto a vintage Danelectro
Developing a professional solution for consumer-level retrofitting where none can be found among experts
Webpages provided for owner of guitar and participating technicians
This image shows the same 6-string intonation points for each string that's shown in the above image. The orange dots here show the approximate points where each of a 12-string guitar's dupler strings would intonate ...the first 3 duplers the same as each's Spanish string matching note and string gauge, while the last 3 duplers are an octave higher and smaller gauge than their partner Spanish strings, which put the duplers' intonation points back at about the same intonation points as the first 3 dupler strings. A fixed saddle is cut for 12 strings by cutting the saddle ridge flat and the width of the dupler strings offset; Then the proper steeper angle is cut for each string so each string rides on it's own correctly intoned ridge. A fixed 12-string saddle is adjusted / set by averaging the intonation of each Spanish and dupler string pair, making them choral similar to the way a piano's multiple strings for each note is tuned. Actually, the original Danelectro straight saddle 12 string bridge worked well, with a rather strong chorale when the saddle was set properly, ...but it is just requires advanced understanding and process to set those saddles, which the general public did not understand nor care to learn and deal with.
Vintage Danelectro bridge plate.
Custom cut fixed intonation saddle.
Fore-aft slot that a clamping screw from underneath rides in to allow fore / aft and horizontal angular adjustment of fixed saddle.
But first let's look at how the bridge plate and bridge saddle was arranged and adjusted on old
vintage and old vintage style 1998-2003 Reissue Danelectros; It will help understand the challenge:
2 holes on each corner of the front of the bridge plate were counter sunk on their bottom side to sit on top of 2 large flathead phillips wood screws that were the bridge posts screwed into the top of the body and down into the sound / bridge block inside the body.
The bridge plate also had one hole in the center of it's rear that was counter sunk on TOP of the bridge plate; And a screw identical to the front two bridge post screws is inserted through the TOP rear screw hole and down into the sound / bridge block (see picture below). The bridge plate just sits on top of the front two bridge post screws via the 2 front holes that have counter-sunk cups on the bottom of the holes that fit onto the top of the screws; The holes are provided to adjust the screws up and down for the FRONT bridge height. The screw through the top of the rear hole prevents the bridge from flipping forward from string tensions when the guitar is strung, and the rear screw provides height adjustment for the rear of the bridge, again with string tensions pulling up on the rear of the bridge plate against the rear screw and pushing down on the front of the bridge plate via string tensions upon the saddle.
In the picture below, under the arrow, I have put masking tape to protect the body, because I had to screw the rear of the bridge plate down onto the body so that the bridge would sit tight on the front 2 bridge post screws while I worked on the rest of the guitar; Otherwise the bridge plate would spin & flop around on the rear screw while no string tension to hold the bridge plate down tight on the front 2 bridge post screws.
The bridge saddle itself is held onto the top of the bridge by a small screw on the back of the plate that reaches through a slot into the bridge. With the saddle screw loose the saddle can be adjusted fore and aft and slanted on the plate for the best intonation; And there are also 2 tiny tit protrusions on the top of the bridge plate to set each of the ends of the saddle's front edge against for the factory intonation saddle slant position; Then the saddle screw can be carefully tightened to hold the saddle setting in place. The saddle screw doesn't have to be very tight since string tensions will hold the saddle up against those 2 tiny tits, but just tight enough for the saddle to be held by the tiny tits.
Shown to the left is the brass fixed compensation saddle I made for my own personal (and main squeeze) Silvertone 1457, which we will take a look at further below to get some intonation geometry from to see the challenges of determining the best option for the Scorpion's 12 string bridge. (The black bar in front of the bridge is a Roland synthesizer pickup).