Long vs short scale setup question

[thistle3585]

For those that build and/or setup longer scale instruments, do you set the same height at the nut regardless of the scale length? I've been building some octaves and tenors and it seems like I can't get the action as low without buzzing. Also, do you strive for the the strings to be parallel to the board or have a slight increasing angle towards the bridge? Since I don't normally play longer scale instruments, i really don't have a players feel for them.

[HoGo]

For me nut height (meaning depth of slots) as low as it goes (down to original new fret height, I don't lower the slots when I dress frets), though on mandolins I sometimes add a bit which seems to help IMO with chops of the C chord or low A chord.
Action and relief generally the longer and/or lighter the strings are the higher action and more relief I use.
For mandola I would use more relief and higher action than on mandolin with strings of similar tension. On guitars even more. If I setup guitar for 0.013" strings I use lower action and less relief than for similar guitar with 0.010" strings.

[pops1]

HoGo has it right. More tension and shorter scale can have lower action than a lighter tension and longer scale. Even changing to lighter strings on the same instrument you may have to raise the action, a lighter strings vibrates more than a heavier string with more tension.

[Bob Schmidt]

I play a longer scale OM and am still trying to find the best setup. I play fairly hard so I do have to set more relief in the neck. I am still trying to find the sweet spot for the action, but in general higher seems to be better. It probably depends on who is playing the instrument, but most long scale players are primarily playing accompaniment and can be somewhat aggressive, so probably erroring on a higher action if you don't know the players style.

[Tavy]

Since I use a zero fret, the action at the nut is necessarily as low as it can go

So yes, the action must obviously increase as you go along the fretboard.

For something guitar sized, you're looking at guitar style setup with approx 2mm action on the low strings at fret 12. For "in between" scale lengths the action the also "in between" a mandolin at say 1.5mm and guitar at 2mm. As ever the top strings will go lower.

The other thing you have to watch for is the 2 strings bashing into each other and buzzing rather than hitting the frets and buzzing. This is harder to solve, more prevalent with lighter strings, and requires an adjustment to the string spacing at nut and bridge.