Question about fretted notes equally sharp

Ha ha, I am as inclined as my saddles! I angle the saddle to prevent rotation, letting the strings push it down into the bridge. I agree that the ones I show in the previous post might be a tad too angled - one could argue that the string length would shorten if the saddle was lowered. Then again, a lower saddle would mean less stretch when fretting so another one could argue that this means less need for compensation.

When I chose the angle I was aiming to bisect the angle formed by the string, thinking it looked good. And it works for me. Maybe I'm underthinking this, but the ukulele is after all such a happy little instrument... it goes drring drring plunk plunk and the beer is cold and everyone so friendly.

I don't think anyone does this by measuring. The process is pretty simple for me:

Compare 12th string harmonic with fretted note at the 12th.

If the fretted note is sharp, take the saddle back a little at that point (I just slacken the string and move it out of the way).

Repeat until both notes are the same.

I usually do this with a chisel, and then when all four strings are intonated I remove the saddle and tidy up my chisel marks with sanding.

For a 13 inch scale soprano using Aquila strings with action 2.5mm at the 12th the C string compensation will be around 2.5mm, the E string about 1.25mm, and the G string maybe 0.5mm. The numbers will be lower on longer scales.

This is something a player can learn to do for him or her self. Buy a spare saddle, sand it to fit the slot, and then go to work. However, the first thing to fix is the nut height, which might require deepening the saddle slots. A high nut is the worst culprit for poor intonation.

Once the nut is sorted, drop in the spare saddle and get the height right at the 12th fret. I find 2.5mm (measured from top of fret to bottom of string) good for most players, but a heavy strummer might want 3mm, while a player of fast runs might want 2mm. Take the saddle down by sanding the bottom, marking a line on it to make sure you sand evenly. If you go too far, throw the saddle away and buy another one.

When the action height at the 12th is good, set to work on the compensation. A chisel (tiny shavings), baby file, or sandpaper stuck to a thin stick, all will do the job. On a moderately priced factory uke you will have a plastic saddle, which is very easy to work. Bone or some hard composite like Tusq is slower work, but not difficult. For first attempts, use something like cardboard to protect the top against slipping with whatever tool you're using.

When you're nearly done, don't forget that the top of the saddle needs to be rounded, so build that in as you're taking the peak back.

And if it all goes horribly wrong, put the original saddle back in and you're no worse off!

ProfChris said:

I don't think anyone does this by measuring.!

Click to expand...

Excellent post! Basically dial it in. Good advice.... However, this predisposes that the scale length and compensation is "ball park" close. You are only going to get about a 1/16 inch wiggle room forward or backwards on the saddle, so get it close to begin with.... Also I agree that a the too high nut is responsible for some of these bad intonation issues on poor setups. And also, if you have not done this before, go slow and don't take too much material or you have just ruined your saddle. Hello shim! Saddle shims are totally lame and suck up sound! Use a tuner and go slow. And like he says, have a spare saddle ready to go just in case. Be happy if you can get it to one cent.

Edspyhill05 said:

Update: today I finally had time to work on this baritone Uke. I took just a bit of wood off the front of the nut and now the fretted notes are in tune with the open strings. I can't explain this but it may have been the nut was uneven and the nut slots were cut incorrectly. I'm guessing that the forward string nut slots were filed. So the actual witness point was back toward the tuners.

This old baritone ukulele sounds awesome for its age and being all laminate wood. The last task is to lower the saddle slowly. It's the second one I made for the new bridge and wanted to wait until I fixed the nut problem.

Ed

Click to expand...

One last update. The consensus that the nut was too far from the saddle was accurate. Turned out that it is just that the rosewood nut was not slotted properly and it is warped. Someone filed the slots so the high side was toward the tuners. I got the intonation very close but the nut is just not right. The last step will be to make a new bone nut.

I also lowered the saddle to lower the string action. I left it at about 3mm at the 12th fret. I'll leave it there for now.

Thank you to all for your generous and invaluable advice.

Ed

Edspyhill05 said:

Someone filed the slots so the high side was toward the tuners.

Ed

Click to expand...

Yes, having the nut in backwards would seriously mess up intonation. Glad everything worked out and ended happily. Aloha.

One last update. I got the Uke almost fixed by cutting slots deeper in the old nut, but it was not perfect. So, I finally took the time to order bone saddle/nut material. Saturday I tapped the rosewood nut off the fingerboard. It had an unusual shape that was completely visible only after it was removed. The nut was “crowned” with three surfaces on the top of the nut, and the entire front of the nut was not perpendicular to the fingerboard.

I made a new bone nut, cut the string slots for a low action. This old baritone ukulele sounds so sweet. It is a shame this Uke, since the late 1960’s, was considered a crap instrument that played sour, out of tune chords.

All it took was a new bridge, a new bone saddle, and a new bone nut.

Thanks to all, again, for this discussion.

Ed

Edit: I don’t want to give the impression the Uke now sounds like a solid top instrument. The chords are in tune at least up to the seventh fret. A little fine tuning of the nut will smooth out the intonation a bit more.