Determine Bridge location

[Mad Russian]

So I recently acquired a P-Bass body. Seems to be an early Warmoth P-Bass. It is a P-Bass top rout with standard neck pocket. However the bridge was never drilled for. How do I go about setting the bridge location? I could probably take another p-bass body and come up with a jig. Any other ideas?

 

[LowendinFL]

It needs to have a neck on it first. It depends on the scale of the neck going on it.

 

[Mad Russian]

34" Scale. I have a neck. How do I line it up left to right?

 

[Beej]

Search for "bridge location", "locating a bridge", bridge alignment" for more threads with lots of detail, as this question gets asked a few times a year.

LowendinFL is right, you need to fit the neck you'll be using first. If your question above was regarding aligning the neck left to right, either you haven't tried the pocket yet, or your pocket may have too much play. The neck should be snug and not have much side to side wiggle room.

If this is a total parts bass, you may also want to fit your pickguard and pickup into the proposed location as well, to ensure the strings will line up over the pickup properly.

Once you have your neck aligned, you need to find the centreline. Do this by running a straightedge down the side of the neck onto the body and draw a straight line following this right down the body past the bridge location. Do this on the other side as well, and you'll have two lines that follow the sides of the neck and carry on over the body to the end.

Next you need to find the bridge witness line. This is found by measuring 17" from the centre of the 12th fret. Mark this on either side of the bridge lines, and then draw a perpendicular line across the 17" mark (34" from the nut), as this will become your witness line for estimating the saddle location.

Now you can find the centreline of the bass by finding the line directly between the lines you drew from the sides of the neck to the butt of the body. You need this centreline visible on either end of the bridge to help locate it.

From there, you can just mark where you want it, predrill and mount your bridge. Make sure that when you place the bridge, you first zero all the saddles and then move them about 1/8" towards the back. This is your zero location. Place the G string saddle (or whatever your highest string is) right over top of the witness line - the rest of the saddles will be moving back from the witness line when you intonate the bass later.

Pictures would help this description a LOT, which is why I recommend looking up some pictorials. There are also good resources in the stickies at the top of this forum...

 

[RPIcka]

On a 34" scale bass, if you are using a Fender replacement style bridge, a Gotoh 203, a Hipshot bridge or Schaller roller type, it should measure 35 inches from the nut to the center of the bridge mounting screw holes. Typically what should happen is the saddles will be around 34 inches from the nut to the saddle if the saddles are zeroed on their intonation screws, meaning they are half way from their sharpest and flattest point.

 

[Mad Russian]

yeah seems I didn't search enough. Found some other threads. Thats for the help though!!

 

[Beej]

On a 34" scale bass, if you are using a Fender replacement style bridge, a Gotoh 203, a Hipshot bridge or Schaller roller type, it should measure 35 inches from the nut to the center of the bridge mounting screw holes. Typically what should happen is the saddles will be around 34 inches from the nut to the saddle if the saddles are zeroed on their intonation screws, meaning they are half way from their sharpest and flattest point.

In theory, this explanation of the zero point is true. In practice, unless one is restringing with light gauge strings for a piccolo configuration, the saddles will never need to move forward for adjustment. So further in practice, one does not need to accommodate positioning for neckward movement of the saddles.

What this means is, in practice, saddles are zeroed by putting them all the way to the neckward adjustment on their screws, and then tightening about 1/8-1/4" away from the neck. This will allow much more adjustment room for the use of larger string sets and still gives you plenty of room for forward adjustment if at some point someone wants to string it with a piccolo gauge.

Locating a bridge over the scale line at the middle of its adjustability just limits its ability to be adjusted in the future...

 

[Greenman]

In theory, this explanation of the zero point is true. In practice, unless one is restringing with light gauge strings for a piccolo configuration, the saddles will never need to move forward for adjustment. So further in practice, one does not need to accommodate positioning for neckward movement of the saddles.

What this means is, in practice, saddles are zeroed by putting them all the way to the neckward adjustment on their screws, and then tightening about 1/8-1/4" away from the neck. This will allow much more adjustment room for the use of larger string sets and still gives you plenty of room for forward adjustment if at some point someone wants to string it with a piccolo gauge.

Locating a bridge over the scale line at the middle of its adjustability just limits its ability to be adjusted in the future...

^ what he said

 

[80'sRocker]

I was also wondering the same exact thing, so far pretty helpful. Thanks

 

[RPIcka]

In theory, this explanation of the zero point is true. In practice, unless one is restringing with light gauge strings for a piccolo configuration, the saddles will never need to move forward for adjustment. So further in practice, one does not need to accommodate positioning for neckward movement of the saddles.

What this means is, in practice, saddles are zeroed by putting them all the way to the neckward adjustment on their screws, and then tightening about 1/8-1/4" away from the neck. This will allow much more adjustment room for the use of larger string sets and still gives you plenty of room for forward adjustment if at some point someone wants to string it with a piccolo gauge.

Locating a bridge over the scale line at the middle of its adjustability just limits its ability to be adjusted in the future...

I didn't realize the original poster was going for a piccolo bass.

 

[tjmdetroit]

Beej ... Good job explaining, even without the pics.... thanks for the effort!!
Tim

 

[Beej]

I didn't realize the original poster was going for a piccolo bass.

I don't believe he is, its just that its the only reason to move the zero location back from the full neckwards position of the saddles. Otherwise, it makes most sense - in order to get maximum adjustability from the bridge - to set the saddles as far neckward as possible and then locate the saddles over the scale witness line. My explanation above was designed to support the final statement: "Locating a bridge over the scale line at the middle of its adjustability just limits its ability to be adjusted in the future".

The explanation you offered for the zero point "saddles are zeroed on their intonation screws, meaning they are half way from their sharpest and flattest point" will limit the bridge's maximum adjustability by nearly one half. I noticed this tidbit and clarified for others to help them not make that mistake. The zero point is actually all the way to the flattest point on the intonation screw, minus about 1/8-1/4" to the sharp side...

Tim, thanks...

 

[RPIcka]

I don't believe he is, its just that its the only reason to move the zero location back from the full neckwards position of the saddles. Otherwise, it makes most sense - in order to get maximum adjustability from the bridge - to set the saddles as far neckward as possible and then locate the saddles over the scale witness line. My explanation above was designed to support the final statement: "Locating a bridge over the scale line at the middle of its adjustability just limits its ability to be adjusted in the future".

The explanation you offered for the zero point "saddles are zeroed on their intonation screws, meaning they are half way from their sharpest and flattest point" will limit the bridge's maximum adjustability by nearly one half. I noticed this tidbit and clarified for others to help them not make that mistake. The zero point is actually all the way to the flattest point on the intonation screw, minus about 1/8-1/4" to the sharp side...

Tim, thanks...

I was going by this http://www.stewmac.com/FretCalculator which puts the saddles roughly where I stated. Maybe Stew-Mac is wrong.

 

[fu22ba55]

Just as an aside... if anyone searches and finds this thread, be aware that Warmoth drills their Gotoh 201 holes 1/2" further back then where standard fender bridge holes are:

http://www.talkbass.com/forum/showthread.php?p=9434795

It makes perfect sense if you're using a Gotoh 201 or Badass II since they have so much travel, but if you're using an old Fender bridge, or direct fender replacement (like a Hipshot 'A' with fender holes), you won't have enough travel to intonate the G string.

 

[pedulla-2007]

Bass brother Beej answered all my questions too.Many thanks!

 

[Beej]

I was going by this http://www.stewmac.com/FretCalculator which puts the saddles roughly where I stated. Maybe Stew-Mac is wrong.

I've never read that link before. Not that I think its wrong per se, but it does not give enough information to correctly mount a bridge. For example, if you used that recommendation and mounted a Fender bridge by lining up the screw holes with the 34" witness line, you'd have absolutely no adjustability for intonation. In fact you would not even be able to intonate it, as the saddles would be maxed out before you even started to adjust it. So in that case, the bridge locator page above is misleading.

A consistently accurate way to locate a bridge for accurate intonation and maximum adjustability is to do it as I described. I'm not making this up, take a ruler and check your instruments. And its worth noting I'm certainly not alone in my understanding of this...

 

[pilotjones]

I'm with Beej but for one thing. Do you have any evidence that with thin or piccolo strings you might have to adjust the witness forward of the theoretical bridge line? I would definitely like to know. Theory does not support it, and I'm unaware of any evidence that does.

When I started a thread to address this specific subject, no one had ever heard of a verifiable case where saddles had to be moved forward rather than backward of the theoretical line to intonate.

So, as far as I know, both theory and practice properly lead to a procedure where you adjust your saddles all the way forward, place the resultant witness points on the theoretical bridge line, screw down, and intonate. In the thread, a few luthiers said that they put the saddles a smidge short of full forward just in case, but they had never had to use that extra travel.

 

[Beej]

The first time I've ever come across this was recently when I helped a friend change his fiver from a low B configuration to a low E. Its now EADGC. When we changed the G to a C string, in order to properly intonate it, I had to move the saddle about 3/32 towards the nut. This was to my recollection the first time I had paid attention to a saddle's motion and noted that it did need to be shortened. Its still right in the neighbourhood of the 34" witness line though, but its a good point - its such tiny amount its almost not worth needing to accommodate it...

 

[pilotjones]

The first time I've ever come across this was recently when I helped a friend change his fiver from a low B configuration to a low E. Its now EADGC. When we changed the G to a C string, in order to properly intonate it, I had to move the saddle about 3/32 towards the nut. This was to my recollection the first time I had paid attention to a saddle's motion and noted that it did need to be shortened. Its still right in the neighbourhood of the 34" witness line though, but its a good point - its such tiny amount its almost not worth needing to accommodate it...

Yeah, my guess is that the compensation was 4~5 /32 before readjustment, and 1~2 /32 after.