Shortscale to Long scale convertion (?)

Theoretically possible. Practically ..... not really. Bridge will need to be moved back, perhaps past the end of the body. So you may need to build an extension to the body or design a bridge that will extend past the end. That's what I mean about being impractical.
 
why do i have to move the brigde back?
The longer scale neck will have wider fret placement. That means that the distance from the nut to the 12th fret will be longer than a short scale. The bridge must be located at a distance from the 12th fret that is equal to the distance from the nut to the twelfth. Since that nut-to-12th distance is longer, so the 12th-to-bridge distance must also be lengthened. Thus the need to move the bridge back. Otherwise everything but open strings will be out of tune, getting worse as you go up the neck.
 
  • Like
Reactions: Jimmy K9 and BeeTL
You may be able to split the difference- move the bridge as far back as possible, then add a block in the end of the pocket to give more distance to the nut.
A 34" scale bass will be 34" from the G saddle to the nut.
Lay it out first before buying or cutting anything.

BTW: I have a 35" scale neck on an Ibanez RG body (had to mount the bridge at the end of the body, and the end of the neck is against the neck humbucker route) but it's 35" scale, and was made for a pickup test bass.
 
  • Like
Reactions: BeeTL
Here's an illustration:

Short-Long Scale.jpg


The yellow line aligns the heel of the long-scale with the pocket end on the short scale. In order for the instrument to play in tune, the distance from the twelfth fret to the bridge must be equal to the distance from the nut to the 12th. So the red line shows where the bridge would need to be.
 

Attachments

  • Short-Long Scale.jpg
    Short-Long Scale.jpg
    76.7 KB · Views: 2,485
+ you need to allow for compensation so the distance from the 12th fret to the bridge saddle will be a little more than from the 12th fret to the nut.
The short scale jag body is definitely smaller than the long scale version. Even if you could get a bridge in the right place, the bass would have neck dive issues.
 
  • Like
Reactions: Jimmy K9 and BeeTL
Turnaround's picture shows why, but if you want numbers; on a long (34") scale bass, the distance from the nut to the 12th fret is 17", so the distance from the 12th fret to the bridge saddles has to be 17", too (17 + 17 = 34). On a typical short (30.5") scale bass, those numbers are 15.25" + 15.25". To turn it into a long scale bass, you would have to move the bridge saddles back 1.75" (half the difference between 30.5 and 34). And, unfortunately for you, there just isn't enough room on most short scale basses to do that. You might be able to do it with a 2-piece bridge, or something, but... probably not. Personally, I could do the conversion with my Gretsch Broadkaster (I've done the math), but it would cost a fortune (custom trapeze tailpiece, custom set neck, plus the labor..:eek:). And, since it's one of only 2 lefty Gretsches I've ever seen, I'm not about to screw with it...:)
 
  • Like
Reactions: Jimmy K9 and BeeTL
Jim_Dragons, Turnaround has given you an excellent visual representation of the issue: everything on your short-scale instrument is designed to scale. The distance from bridge to nut is built so that the overall length is 32". You can't just slap a long scale neck on without changing the scale of the entire instrument.

Even if the long scale neck fits, your overall length from bridge to nut WILL NOT be 34"...probably closer to 33.2", which would mean all the fret spacing was off, and no fretted note would be correct. You have to move the bridge to make the overall scale length correct.
 
  • Like
Reactions: Jimmy K9 and BeeTL
What you're talking about can be done, but the neck has to be designed specifically for that purpose.
As far as I know there aren't any currently in production for 30 to 34" conversion.
With guitars it's easy to find necks that convert 25.5" to longer or shorter scales without moving the bridge:
ConversionNecksCompared.jpg
 
  • Like
Reactions: BeeTL
Jim_Dragons, Turnaround has given you an excellent visual representation of the issue: everything on your short-scale instrument is designed to scale. The distance from bridge to nut is built so that the overall length is 32". You can't just slap a long scale neck on without changing the scale of the entire instrument.

Even if the long scale neck fits, your overall length from bridge to nut WILL NOT be 34"...probably closer to 33.2", which would mean all the fret spacing was off, and no fretted note would be correct. You have to move the bridge to make the overall scale length correct.

If those numbers are correct, a .80" spacer in the end of the pocket will move the neck out far enough for scale length.
The question then, is- will there be enough of the neck heel in the pocket for stability?

The more frets on the neck, the farther out the nut will be with the heel still bedded in the pocket. A 24 fret neck may be more than you need w/o moving the bridge (it's got nowhere to go, at the end of the body, anyway). Best to lay out the measurements from G saddle to end of pocket, then from G saddle to nut (34") to see how long the neck needs to be.

Edit: If the body is for 32" scale, actually, a 22 fret neck with a 1/2" spacer should do it, 24 frets will be too long, unless you route the pocket a little.
 
Last edited:
  • Like
Reactions: BeeTL
You can make a short scale a long scale by changing the neck IF that neck is designed to do so, it would almost certainly be a custom job and the realitive pickup locations will change to be closer to the bridge so it won't sound the same as a regular jaguar. I think @BeeTL and @Bruce Johnson have experience doing such a conversion, but it will cost you quite a bit.
 
  • Like
Reactions: BeeTL
You can make a short scale a long scale by changing the neck IF that neck is designed to do so, it would almost certainly be a custom job and the realitive pickup locations will change to be closer to the bridge so it won't sound the same as a regular jaguar. I think @BeeTL and @Bruce Johnson have experience doing such a conversion, but it will cost you quite a bit.
Actually, my necks convert a standard 34" to 32" with no modification.

It's actually quite simple, and I'm surprised it had never been done before.

By contrast and as detailed above, converting a 30" to 34" is fraught with difficulties.
 
Actually, my necks convert a standard 34" to 32" with no modification.

It's actually quite simple, and I'm surprised it had never been done before.

By contrast and as detailed above, converting a 30" to 34" is fraught with difficulties.
You can do the same thing that you do but in reverse, the same math that makes it easy to convert the longscales to medium and short scales makes it simple to convert a short scale to a long scale, you just have to deal with the extra neck dive and having the pickups in the wrong spots.
A 22 fret neck should work.
 
Last edited:
  • Like
Reactions: BeeTL