Installing a bridge on a body

[Metalmoore]

Ok, so i bought a jazz body with only the pickups and control part routed, how would i go about and put in a bridge? do i just screw it in? or do i do something else, unsure on what to search either... Thanks for any help.

[The Bass Doc]

Strangely enough you need a neck on first. When you say you have, the guys will chip in with certain formulae.

[Mr. Foxen]

The bridge is adjustable, so mm precision length wise is not so important, Side to side is much more so, have the neck on and the two outer strings to make sure its righ, mark it, and check it again. Remember you want the saddles to be slightly longer distance from the 12th fret than the nut is, due to intonation adjustment.

[BOD2]

You also need to run a ground wire from a ground connection (i.e. a pot shell) in the control cavity and trap it between the underside of the bridge and the body. This will ground the strings and prevent all sorts of noises when you touch the strings.

There should be a hole drilled from the bridge location to the control cavity to pass this wire through.

[Metalmoore]

[quote name='BOD2' post='504454' date='Jun 3 2009, 09:32 AM']You also need to run a ground wire from a ground connection (i.e. a pot shell) in the control cavity and trap it between the underside of the bridge and the body. This will ground the strings and prevent all sorts of noises when you touch the strings.

There should be a hole drilled from the bridge location to the control cavity to pass this wire through.[/quote]

Yeah this is what i really wanted to know, the body doesnt have anything to link between the control cavity and where the bridge will be... Any tutorials to do it?

[BOD2]

This is how you place the bridge. Seems complicated but follow it step by step and it will makes sense.

First you need to know the scale length of the neck. For a Fender Jazz or Precision bass the scale length is 34 inches. If it's something other than that then you'll need to establish that first.

If the body is finished, protect the finish of the bass against scratches before you start. You'll need to draw lines in the body so stick masking tape over those areas.

1. Insert the neck into the neck pocket and hold it in place with 2 or more screws. You can clamp it if you prefer butdon't damage the frets.

2. Use a long straight edge to draw two lines from each side of the neck to the back edge of the body. Run the straight edge along the edge of the neck to ensure the lines are parallel to the neck.

3. Accurately measure 3 inches from the last fret, along each line, and mark this point on the lines.

4. Draw a line across the body between these two marks.

5. Measure the distance along one line from the last fret to a point about an inch from the back edge of the body. Mark this on the line then mark the same distance from the last fret on the other line.

6. Draw a line across the body between these two marks.

7. Measure the centre points of the two lines drawn at step 4 and 6 above. Draw a new line the length of the body through these two centre points.


If you have measured everything accurately so far, then this last line represents the centreline where the neck passes through the body. This line is one of you datum points. Check visually that this looks to be in the correct position.


8. Measure back from the nut 34 inches. Draw a line at right angles to your centreline at this 34 inch point and make it wider than the bridge width. This new line is the "scale reference line".

9. Pickup the bridge and move one of the saddles to its furthest forward point, then move it back 1/16 inch. Measure the distance from the string break point on this saddle to the front edge of the bridge. Measure this distance from the "scale reference line" (step 8) towards the neck. Draw a line at right angles to your centre line at this point - this line represents the front edge of the bridge. It will be closer to the neck than the "scale reference line"

10. Measure and mark the centre of the bridge. Place the front edge of the bridge on the line drawn at step 9 with the centre point of the bridge on the centre line. Mark both sides of the bridge (these marks should be parallel to the centre line). You now have a front edge and two sides marked for the bridge.

Check the positioning of the bridge visually. Does it look right ? If not check your measurements and start again, if necessary.


Note that the strings will always intonate longer than the 34 inch scale, not less. Thicker strings will intonate farther than thinner strings. Because of this, only the G string will be relatively close to 34 inches.

Apologies for the "imperial" measurments but the scale length is 34 inches. This sounds easier than 863.6 mm and I didn't want to mix inches and mms in the same text !

[BOD2]

[quote name='Metalmoore' post='504574' date='Jun 3 2009, 12:05 PM']Yeah this is what i really wanted to know, the body doesnt have anything to link between the control cavity and where the bridge will be... Any tutorials to do it?[/quote]

Mark where the bridge will be going. You know this area will be covered so it doesn't matter too much if you make a mess here !

You'll need a long drill bit to drill at a very shallow angle from under the bridge position and into the control cavity. Getting this hole started might be tricky as the drill will tend to slip because of the shallow angle. It's probably best to use a bradawl and get a good, deep starting point first. This will help get the angle right too.

Just make sure the angle is shallow enough that you come out in the control cavity.

[Metalmoore]

This bridge placement is a pain in the arse... im confused about step 5. Do i measure an inch back on the 2 lines and make a mark and then connect them or do i measure an inch on one line then measure the distance between the last fret and that mark then mark that distance on the other line and connect the two?

Just i really dont wanna end up with a bridge in the wrong place or a bunch of screw holes from previous attempts.

[BOD2]

[quote name='Metalmoore' post='531831' date='Jul 3 2009, 04:53 PM']... im confused about step 5. Do i measure an inch back on the 2 lines and make a mark and then connect them or do i measure an inch on one line then measure the distance between the last fret and that mark then mark that distance on the other line and connect the two?[/quote]

The reason behind this is that the body might have a curved or sloped shape at the back edge, therefore you cannot measure accurately from the back edge of the body towards the neck. What you are ultimately trying to do is to get a line across the body, near the back edge of the body, that is exactly at right angles to the neck.

Measure back along one of the lines approximately one inch from the back edge of the body and mark this point.

To get a line at right angle to the neck you need to measure the same amount along the other line. Since the body might not be straight, you can't measure from the back edge of the body. So measure from the last fret to the mark you just made on the first line and note this measurement. Now transfer this measurement from the last fret onto the other line - mark this and you'll have two marks near the edge of the body exactly the same distance from the last fret.

Sorry it seesm so complex - it's the potential for curved body shapes that makes it like this.

[mrcrow]

you need the neck and nut on the body...initially
measure 34" from the nut...thats where the G saddle will be and put a piece of masking tape on each side of the bridge position and mark the 34" position
set your bridge with the saddles 3/4 the way out from the full back adjustment
line those up with the 34" marks...mark through and drill the fixing holes etc

as for the earth from the bridge

run a copper strip from the bridge front over the body and down into the bridge pup cavity...solder a wire to it and lead that to the control cavity to be soldered daisy chain to whatever pot you are using for the jack earths

the option is to drill a horizontal hole from the control cavity to under the bridge are and pop a hole through to that to take a cable....too hard for me

good luck