MIMF

Building a 5string fretless for my father inlaw. The bridge is a kahler 2450. My question is placement. Where should the bridge lay in relation to the theretical end of scale line?

Jonathan,
Do you have the bridge in hand?
Start by moving all of the saddles to their forward-most positions. Draw a line across the body at the end of the scale. Because this bridge is staggered I would line up the middle (A) string saddle breaking point with the line. If the B string saddle is more than 1/8" behind the line I'd move the whole bridge forward by 1/32". Now move the G string (or C string) saddle as far back as it will go and make sure it's at least 1/16" behind the line. If you can't meet both those criteria you will limit the string choices that will intonate to the stiffer strings on the market i.e. lower quality strings.
In my view staggered bridges are a solution in search of a problem.

Technically, for a fretless it doesn't matter. This is why bridges on violins and upright basses are not intonated. You just have to get them to the right scale length.

Personally I intonate my fretless basses to the imaginary 12th fret, but on a fretless intonation is up to the player.

Thanx guys. I still can't believe it didn't come with any literature at all.

That's not the least bit surprising to me.

My experience on my 5 strings , one of which is fretless is that you need about 1/16 extra on the G string and 3/8 on the B string (with taper wound B) and a little more if the B is not tapered.

Jeff Highland wrote:My experience on my 5 strings , one of which is fretless is that you need about 1/16 extra on the G string and 3/8 on the B string (with taper wound B) and a little more if the B is not tapered.

Did you have lines on the fingerboard? If not it doesn't matter, because you will place your finger where the note is in tune, and not in some fixed position, as on a fretted neck. This is how an upright bass is. There is no compensation at the bridge. You have to correct for intonation.

Well its a conversion, I have faint lines so I intonate to that at the 12th