flat or curved bridge?

[PH-Mando]

I have a mandolin with 12 inch radius fretboard, but the bridge is flat across the top. Is that good or bad? Should arched bridge be paired with arched fretboard?

[MediumMando5722]

The bridge should be arched to match the board.

[Rodney Riley]

If not arched like the fretboard. D and A string will be close to the fretboard and could buzz. The G and E stings will be farther away and harder to fret.

[EdHanrahan]

Yeah but... Don't think of it as "putting string notches into an arched bridge". More properly, think of it as "putting whatever string notches are needed for correct playability", and the arch will take care of itself. More specifically:

Set the bridge height for the D and A strings, then file the notches for the G and E strings lower until they are correct. When all strings are playing to your satisfaction, simply remove any excess bridge height, being anything above the widest point of each string. The saddle will now match the arch of the strings, which will match the arch of the fretboard.

[MediumMando5722]

If you keep the existing bridge, you’ll need to file the G & E saddles down first, then make the slots. If you just cut the slots deeper to accommodate, they’ll be too deep.

[AndyV]

Out of curiosity, with a 12' radius what is the height difference at the 15th fret (or 17th or.... You tell me) relative to the horizontal from the outside strings?

[Louise NM]

I get the feeling that bridges and fingerboards are often mismatched. I took my 30-year-old mandolin in to have some work done on it. The first thing the luthier noticed was that the instrument has a flat fingerboard, but some poor misguided soul had put an arched bridge on it. He also looked at my second instrument; it turned out to have a radiused fingerboard and a flat bridge.

[PH-Mando]

I don't have the correct type of files to cut the slots for the strings. I appreciate the all the great suggestions. Maybe I should just buy an arched bridge but keep the existing base which has been fitted to match arch of instrument

[OneChordTrick]

Out of curiosity, with a 12' radius what is the height difference at the 15th fret (or 17th or.... You tell me) relative to the horizontal from the outside strings?

My “back of the envelope” calculation suggests 0.06” or about 1.5mm. But I may wrong, it’s early here, I’m still in bed...