Action Adjustment

I'm back playing Uke after a 32 year sabatical. My wife bought me a Mahalo U-351 from Hammicker Schlemmer (paid too much). It looks like a solid Mahogany top and Koa (solid?) sides and back. Sounds pretty good but the action out of the bag sucks. I sanded the saddle which helped alot but still can't play a first fret bar without lots of effort. I'm thinking (and dreading) of taking a file to the nut. What sort of clearances should I be shooting for?

You should use purpose made nut files. Get them in appropriate dimensions from Stewart MacDonald. You can rock them from side to side a bit to make a larger slot than the nominal size.

The action at the nut should feel much like it would if you capoed the uke at the first fret and played it. In other words, the action should be like it's coming off of a fret. It's REALLY easy to file too far. Take your time.

Good action at the nut will even make the action noticeably better way up the neck.

Rick Turner said:

You should use purpose made nut files. Get them in appropriate dimensions from Stewart MacDonald. You can rock them from side to side a bit to make a larger slot than the nominal size.

The action at the nut should feel much like it would if you capoed the uke at the first fret and played it. In other words, the action should be like it's coming off of a fret. It's REALLY easy to file too far. Take your time.

Good action at the nut will even make the action noticeably better way up the neck.

Click to expand...

Both because it's easy to go too far, and also to account for any wear over time (albiet much less on a uke than a steel string guitar), i like to have the string height at the nut just a little more than when compared to a fretted string.

A lot of ukes have an ebony nut also,.....which seems to me could wear a little faster than a bone or ivory one. So i've found adding maybe .3mm or .4mm more than the string clearence gets when fretting the 1st fret is a good place to shoot for. Remember, it's a lot easier to take off height than add it. Having to make (or pay for) a new nut because you filed a few too many strokes is not fun.

... the very slightly higher nut action will not be noticed anyway, once you get the really "extra" nut height off. I've had a few that were 2 to 3 times heigher than optimum string height at the nut,......unplayable. Besides the much harder fretting at the lower fret positions,.....all the notes are noticably sharp.

BTW, i was a bench jeweler for 35 years, (repairman and diamond setter) and used to using small files. I got along fine with 2 small tapering rat tail files for most of my nut slot work. One was coarser and used to get close, with the finer file finishing up. You had to taper the nut toward the headstock sometimes with a sanding block, because a wide nut can't be slotted with a tapered round needle file. ( the taper catches before you get to the far side of the slot)

......but in finishing up my recent Cordoba 25CK adjustment i was day-dreaming a bit and snapped the tip off of the finer file! Looks like i'll be getting a set of nut files at 55 years old! :drool:

You say you sanded the saddle? I always start
at the nut,then check the action/intonation,
before even looking at the bridge!

The action at the 12th fret was just under 1/2". I dropped only 1/8" to get it playable. The saddle was removable and I figured that if I screwed it up I can always replace the saddle. How do I check the intonation? Is that were you make sure the overtone is over the 12th fret?

Are you seriously saying that you have 3/8" clearance between the top of the 12th fret and the bottom of the strings? Great for bottleneck...

Yep, that's why I'm asking how to tweek it.

You need to get the action at the 12th fret close to proper height. Then go to the nut. Then perhaps back to the saddle again. Good action at the 12th fret is going to be around 2.0mm to 2.5mm from the top of the fret to the bottom of the strings for. Adjust for string type and playing preference.

At the nut you fret the string at the 3rd fret and look for just a whisker of space between the top of the first fret and the bottom of the fretted string.

To get an idea of how much to take off the saddle for proper height you will need a straight edge of some sort, a 1/8" diameter drill bit or similar and another short ruler. Strings off of course. Pull the saddle out of the slot, place the 1/8" drill bit next to the 14th fret (yes the 14th and not the 12th) and lay the straight edge so one end is on the 1st fret, middle rests on the 1/8" bit and the other end shoots over top of the saddle slot. Now take that small ruler and measure from the bottom of the saddle slot to the edge of the straight edge. This will tell you how tall to make your saddle for proper clearance at the 12th fret.

Most uke frets are approximately 1mm tall, and a 1/8" bit is 3.2mm. So simple math tells us that this gives us 2.2mm clearance. Reason you go to the 14th fret is because we are using the 1st fret to rest the straight edge on and not the nut. Makes the end of the straight edge raise up a bit over the saddle slot as compared to what the string will actually be.

Thanks for the guidance. Now I just need the courage to take a file to the nut. Hopefully I won't be asking how to replace a nut!

I appreciate the help.

I guess this is as good a place as any to ask my question, since I can't find the answer elsewhere.

I want to do a project with my daughter over christmas to put a bone nut/saddle and new strings on my daughter's ukulele. The nut is already slotted but will need work. I can't afford an entire set of nut files, so I just want to get the ones I need.

The new strings are .191, .256, .340, and .216 (Martins). For the .256 string the options are a .240 file or a .280 file. For the .216 string the options are a .200 file or get a .240 file.

In each case, the files are either .016 smaller or .024 bigger than the string. Is it better to use the smaller file to widen the slot or use the bigger file? How much wider than the string should the slot be, ideally. IOW, what is the limit of excess slot width that would be acceptable?

Thank you.

This might help: http://www.ukuleleunderground.com/forum/showthread.php?45094-Stew-Mac-nut-files

use the next size up nut file.

I use the next size down and tilt them back and forth to get the slot to the width I want.

Ha, Ha. I love it! Thanks for the responses.

I don't know if I have the skill to enlarge using a smaller file, decently, and I don't know how much bigger to make the slot with the larger file before the slot becomes "sloppy".

I guess I'll find out!

Diamond Deb nail file, I'm looking for you....

An inexpensive way to do this is to go to your local welding supply store or maybe a hardwarestore and get a set of welding torch cleaners.If they have two sizes get the long ones. It will cost about 5 bucks. It's a bunch of different diameter wires that have been stamped or cut so that they will work like little files.They are not the best tool to use but they do work.
It wont work well if you are cutting a new nut but if you're just adjusting one it works fine.

I've heard that. It sounds like a good way to touch up the grooves or to clean the grooves after filing...I wonder if the torch cleaners are fine enough to substitute for fine-grit sandpaper?

+1 for welding tip cleaners..

..for hobbiest users. (save many $$$ and still get the job done)

I have made 8 bone nuts with them for my guitars and ukes.

One tip (pun not intended)......ok two.

1. I use various grits of rubbing compound added to the texture of
the cleaners to help them 'cut' or polish more effectively.

2. If you are doing this on the insturment, mask or use a thin piece of cardboard
to protect the headstock from accidental contact with the end of the cleaner.

3 ??
I use a digital caliper to find which cleaner is one size bigger than the
string i am slotting for.

4 ??? Take the one you want out of the little holder to use it more accurately.

General tip.....If you want the bone to look more 'vintage' after you,
size, and polish it, Soak it in a cup of tea to slightly dye it. (works for bone saddles too)

Daysailer:

Thanks for the tips! I appreciate it.

I sanded down the saddle yesterday -- along with my finger tips, LOL. (The slot in the bridge is only 1/16 of an inch.) Funny how satisfying such a simple thing can be.

When I took the strings off the plastic nut I couldn't believe my eyes -- there is nothing but air behind them. The plastic nut is literally hollow. That's just wrong, LOL. I can't wait to get that bone nut on there.

Is it ok to heat the old nut a little bit with a blow dryer to soften the glue or should I just give it a whack?

-BBert.

Geez...if the action is that high I would return the uke. Just no excuse for 1/2" action at the 12th fret without something being wrong. Even cheapie ukes usually have reasonable action these days.

ksquine said:

Geez...if the action is that high I would return the uke. Just no excuse for 1/2" action at the 12th fret without something being wrong. Even cheapie ukes usually have reasonable action these days.

Click to expand...

I thought the same thing when I read the original post. Seems to me that if you have that much clearance at the 12 th fret, there must be something seriously out of whack with that uke. Either built wrong or badly warped or wrong saddle, etc. Unless you bought it "as-is" I would return it.