Potential neck swap for an SX (Rondo Music) bass

[creaturegods]

I'm thinking about buying an SX Ursa 3 bass and an Ursa 2 neck from Rondo Music and I was hoping to get some input from someone more knowledgeable than myself.

Here's the listing for the neck: SX Bass Neck Ursa 2 (SJB) MOP MN - RondoMusic.com
and the measurements:

• Total length: 33 5/16”

• Width of neck pocket (heel): 2 1/2"

• Depth of neck pocket (heel): 3/4" (not counting the fingerboard)

• Width of the neck at the nut: 1 1/2"

• Width of the neck at the 20th fret: 2 9/16"

• Diameter of pre-cut holes for tuners: 11/16"

and here's the listing for the bass: SX Ursa 3 MN ALDER VWH - RondoMusic.com
I emailed the shop asking for neck pocket measurements on the bass body and here's what they sent:
"The neck pocket dimensions on the SX Ursa 3 are
3 3/4" L x 2 1/2" W x 1" D. There may be some modification required to fit the Ursa 2 neck to the Ursa 3 body."

Since the widths are the same, am I correct in assuming this will fit, but might need holes re-drilled and possibly a shim added?

Bottom line, with these measurements, is this neck swap possible? Has anyone attempted this swap on these models?

 

[sissy kathy]

The widths are the same and they should fit together fine; but there's something they aren't telling you. Look at the width of the fretboard at the 20th fret. The width listed there is 2 9/16. Now normally the neck there is not tapered toward the back of the heel, the sides are normally parallel. Something doesn't jive, they list the heel as 2 1/2, but the fret board as 2 9/16. So does the fretboard hang over the sides of the heel, is the heel tapered as you approach the back, is one or the other measurement incorrect? And if it is tapered will the wider portion still fit in the pocket of the body? If one measurement is incorrect, then which one? You may have to carve either the neck or the pocket a little but, given the price, I wouldn't let that stop me. (do the pocket for several reasons.)

You'll need quite a bit of shim for that neck to fit depth wise, normally the neck sits high in the pocket by about a 1/4 inch, and according to them the neck will sit flush. a 1/4 inch full length shim should address that issue. (I'd use a contrasting wood for the shim, trying to match the color will be difficult, so make the shim a design feature.)

 

[creaturegods]

The widths are the same and they should fit together fine; but there's something they aren't telling you. Look at the width of the fretboard at the 20th fret. The width listed there is 2 9/16. Now normally the neck there is not tapered toward the back of the heel, the sides are normally parallel. Something doesn't jive, they list the heel as 2 1/2, but the fret board as 2 9/16. So does the fretboard hang over the sides of the heel, is the heel tapered as you approach the back, is one or the other measurement incorrect? And if it is tapered will the wider portion still fit in the pocket of the body? If one measurement is incorrect, then which one? You may have to carve either the neck or the pocket a little but, given the price, I wouldn't let that stop me.

You'll need quite a bit of shim for that neck to fit depth wise, normally the neck sits high in the pocket by about a 1/4 inch, and according to them the neck will sit flush. a 1/4 full length shim should address that issue. (I'd use a contrasting wood for the shim, trying to match the color will be difficult, so make the shim as design feature.)

This is awesome info. Thank you so much! Great idea with the contrasting wood for the shim, too!