Acoustic Guitar Bridges come in an assortment of different shapes and sizes. The guitar bridge is the essential link in transmitting vibrations from the strings to the soundboard.
It is the fixed point and anchorage for the strings and is the focal point of the string tension. Therefore, if the bridge is not fitted or fixed correctly a multitude of problems will present themselves. Repair example
The guitar bridge should be checked at regular intervals.
Check to see if it is lifting in anyway at its edges. This sort of problem could be caused by soundboard deformation or problems with the internal bridge-plate. Another possible cause could be due to humid atmospheric conditions.
Check for cracks and splits, especially around the bridge-pin area.
A loose bridge will almost always have to be removed in order to clean up the soundboard gluing surface and the under-bridge surface. This will ensure a clean surface for re-gluing.
The saddle on a guitar serves two purposes; one purpose is to set the string height,
the other is to determine the final string length. It is at this point that string compensation is created. On Acoustic guitars this is visible by the angle in which the saddle is set into the bridge. Some Acoustic saddles are shaped along their length to accommodate the varying string gauges. Other Acoustics have split saddles for the same reason.
Electric guitar bridges and saddles are manufactured to a variety of different designs and concepts. Nevertheless, the common aim is to create an individual and adjustable guide for each string. The saddle is the focal point for the string length. From this point the string can be lengthened or shortened so as to set the intonation.
Fender and Gibson have individually adopted unique bridge designs, quite independent and different from each other, but both equally successful. Most other manufacturers have in the main taken on their ideas and adapted them.
Fender Style Bridge
On Fender style bridges the individual saddles are fixed to a bridge plate by adjusting screws which allow the intonation to be fine tuned. These screws are sprung loaded to reduce movement due to string vibration; the bridge plate is secured to the top of the guitar by large screws. The bridge plate is also the string anchorage. All hardware is chrome or gold plated to inhibit corrosion.
Gibson Style Bridge
On Gibson style bridges the saddles are located within a bar shaped housing. The saddles can move to and fro on sprung loaded screws to allow for different string lengths. The complete saddle housing is floated, clear of the body, onto 2 large adjustable bridge posts, which allows for height adjustment. The strings are then guided over the bridge assembly and anchored at a separate tail stop/tail piece.
Tremelo Unit Systems in Brief
Covering this topic thoroughly would probably require a good deal more time and space than is available. I will just endeavour to name the manufacturing pioneers in this particular area. Essentially there are two types of tremelo systems that have passed the test of time. These are the famous through body system adopted by Fender on their Stratocaster guitars and the on-top idea that Gretsch and Gibson used on certain Archtops and electric guitars.
The Kahler and Floyd Rose tremelo ideas have been developed from the Bigsby designs and have evolved to become increasingly more sophisticated over the decades. This type of system is ideal for heavy use.