Any long term readers will remember I acquired via the lovely Mrs F a mandolin a Christmas or so back.
Now I get the thing out from time to time to play along on. But I noticed that it wasn't brilliantly in tune as you moved up the neck. A quick check showed it was not intonated at the 12th fret.
I checked it out using a decent tuner (my Boss TU-15) I figured out that the fretted notes were about 3-4 cents too sharp. Meaning the bridge needed moving back away from the nut end. Now an A style mandolin has a floating bridge - see the picture. So moving it should be possible but how to do this?
Here is the method I used.
1. Mark the location of the front of the bridge on treble and bass sides with masking tape. I put two bits of tape up against the bridge so I knew where it had sat originally.
2. Remove all the strings.
3. The bridge can now be moved/removed. I tried to polish up the top as there has been some colour staining/marking from where the bridge was - I had limited success and didn't want to go into any major hassles I've left that.
4. String up one of the top E and one of the bottom G strings - essentially the two outer most strings.
5. Ensure bridge was a few millimetre back from where it had been previously. Through trial and error I then got the bridge as close as I could to spot on with my trusty tuner.
6. Taped the bridge down with more masking tape to stop it moving.
8. Completed restringing and tuned up.
Result? Much better it is much more in tune with itself now. I'd researched this method online before trying it out and it seems the best way to get a floating bridge in the best place - I'd use it again with an archtop guitar if needed
You can see the amount I moved it back in this picture where the mark left by it's original position on the bass side is notable.