When a rookie tries to make a new nut...

[Melt_in_the_Sun]

I recently acquired a new (old) breedlove oval hole - I wasn't able to play it beforehand, but the seller assured me it was in mint condition. That is true, well, with the exception of the trashed bone nut. Relief was jacked up to some ridiculous number and when I started lowering it, the E strings hit the first fret long before I got the neck straight.

For years I've done minor repairs and setup tweaks on my own instruments and those of my friends/relatives. Nut work was limited to very minor dressing of slots with welding tip cleaners.

I asked a few luthiers in the Tucson area for a cost to have a new nut made. $125 was the cheapest - for that price I could buy a whole set of files and a pile of bone blanks...so that's just what I did. I picked up a set of Uo-Chikyu files and a pack of six nut blanks from amazon. I've read all the instructions, pored over Frank Ford's instructional photos...so how hard can it be, right?

First problem - the crap nut was firmly glued in place. Tapping gently got me this - you can see that one of the G slots has been raised with superglue, and the lower half of the nut is still in the slot before I gently chipped and filed it all out:



Ready to go!



Starting to work on the blank. I cut it roughly to size using a coping saw and started sanding it to size on a sheet of 120 grit.



Well, once it matched the size of the old one, it still wouldn't fit. Looks like I missed a bit of the old bone still in there...removed with a metal pick and now it's starting to look like something:



Used Frank Ford's half-pencil trick to mark a preliminary line:



And with that, we're ready to start cutting slots! I marked the spacing based on the old nut. Getting the strings in shallow slots, correctly spaced, was the hardest part of this. It's a really fiddly process...the files try to scoot to the side, then when you get a slot started it's too close or too far from its neighbors. A painstaking and slow progress, but I got it looking half decent:



I put a capo on the first fret and measured string clearance above the second fret with feeler gauges. It's right about 0.004", so I would file a few strokes, check with the feeler, file a few more strokes, check...and so on. Once I was happy with a slot, I lifted it with a folded sheet of paper so I could get the feeler to the next string. So far so good...



I knew I couldn't succeed on the first try! Turns out that my D slots were not wide enough - I was using the 0.024" file and using the "rock it back and forth" trick to make the slots a hair wider. Not wide enough! I kept on happily filing away, not noticing that the string was levitating above the bottom of the slot.


On to the next attempt! I've got a few more of these...


And, I ruined the second one too...just one too many strokes even though I knew I was close to that 0.004 gauge. My third attempt will use the 0.005, and also attempt to angle the string paths a bit towards the tuners. Got four blanks left!

[pops1]

You can shim a nut if it is slightly low with a piece of paper under the nut. It will not be seen and will work fine. You probably will have to lower the slots once you do this.

[rcc56]

Now you have some idea of why we charge what we do for a mandolin nut.
You've described most of the mistakes most of us encountered while learning.

And if we go for the absolute lowest height for the slots, sometimes even the best of us go one stroke too far, no matter how much experience we have.

There are a few tricks that can be useful. I use a feeler gauge beneath the strings when I fine tune the slots. I set the feeler gauge at least .003" to .005" higher than the fret height, since it is quite common for there to be a little drop off at the end of the fingerboard.
I rough out the slots with the blank in a vise. That makes it easier to keep them square and parallel. I start the front corners of the slots with an X-Acto knife-- it gives the files something to grab on to so they don't wander. I don't cut the nut to final width until I'm finished with everything else. I use one or two drops of glue only.

Make a few dozen more, and it will be easy. Then you can set out your shingle and earn a little money doing set-up work.

[brunello97]

Our great (and sadly departed) friend Pablo Hostetter was a big help to me when I first started replacing nuts on the old Italian bowlbacks I seemed to be accumulating.

Paul's website is still up and here's a link to his page on cutting nuts.

Flush with my success I've recklessly moved on to tuning accordion reeds on my boxes.

There's some fiddly stuff.

Keep at it, you'll get it. And then you'll have it. I shelled out for a set of nut / bridge files and never have regretted it.

I'm not about to hang up a shingle or compete with any pros but I've got it going on for my basic needs.

That said, of course I take my Gibsons up to Elderly when I want anything done proper.

And I'd recommend Ben at Mudlark or Bob Snope, to really tune your button box right.

Mick

[Melt_in_the_Sun]

Pops - yep I know I could shim it, but the point is to learn to do it right! If I start running low on blanks....

I've seen Paul's site and the gist of it is similar to Frank's, though he goes into more detail about precisely shaping the slot itself.

I had no illusions it would be easy! I started this thread mostly for the benefit of anyone later who's considering trying it too. I'm not planning on making any money, but if I can learn a new skill, get my instruments playing better, and possibly help a few friends, it'll be worth it.

[Richard500]

Whether or not the exciting thing is the irreversibility of tiny invisible saw cuts, (it isn’t), the sloping of the cuts toward the tuners really is important so that you’re positive that the string is in best contact at the other side. There’s no harm in going a bit strong on this taper, not with metal strings. Same thing happens at the bridge; the string has to end its vibrating part exactly at the front of the ramps on the bridge, else odd sound will follow. Banjo-like sound to be specific.
After this stage, you can start worrying about the effects of slot pinching on tuning hysteresis (sticking) and possibly when the most auspicious astrological dates for success occur. And how to speak knowledgeably about the inadequacy of other hard, possibly lower friction materials.

[MikeEdgerton]

The amazing thing to me is that if you follow the link on Paul's nut page to his file page there is a link for an item sold by an eBay seller that's still a valid link. Paul's been gone a few years now.

[Explorer]

Here's my method. It's not quite as quick and dirty as the half pencil solution, but I've never overcut a slot since adopting it.

I bought a couple of different sets of nut files from Philadelphia Luthier Supply, which allow me to combine them and get almost any gauge I need. That was worth it to me, since I knew I'd be using them over a long period of time, for many instruments.

I start with leveled and crowned frets. I wrote down the exact target heights I needed for each string slot.

I then learned from videos regarding the StewMac neck caul, which holds feeler gauges firmly against the nut.

http://www.stewmac.com/luthier-tools...lot-nut-guard/

http://www.stewmac.com/luthier-tools...rule-6282e9ad/

I also bought one of the logarithmic string spacing rules. I mark my outer strings, then the inner strings of the outer courses at the right spacings / distances, then marking the right-most strings of each course and the left-most set.

Then, instead of the neck caul, I just use rubber bands to hold the appropriate total set of feelers against the fretboard against the nut, adding an increasing amount of mills to the height as I go from treble to bass courses. The videos show how this method avoids cutting too deep.

Since I'm not a pro and don't have power tools / sanders and such, this method has saved me a lot of time from cutting too deep and having to make new nuts. The feeler gauges prevent overcutting.

However one decides to go about doing this, good luck!

[Tom Haywood]

Thank you, Melt_in_the_Sun, for posting such a good perspective of someone's first effort to replace a nut. I'm sure this will be helpful to a lot of people in the future. Every issue that you faced can potentially show up with any mandolin and any nut blank being worked on by any experienced luthier. I wonder what you now think would be a fair price quote from an experienced luthier prior to starting the work.

[Tom Haywood]

I started work this week on a new violin that needs to be taken apart because the neck angle is not correct for a proper action. The finger board was over-glued at the factory (and also not completely glued down), so it took about an hour to get it off instead of an estimated 15 minutes. The ebony nut was not glued to the neck (as expected), but it was basically welded to the end of the finger board. No one would expect that. I broke the nut trying to tap it off before I found the problem. Thankfully, experience taught me to order a new nut blank before I started. Now, I get to spend extra time and money to make a new nut. Should I include these issues in repair estimates in the future? Should I be willing to eat these additional costs when they show up? Should I not work on this brand again or maybe double the estimate, so the owner will take it to someone else? This is the repairman's dilemma.

[Melt_in_the_Sun]

Ira - I'll take it; thanks!

Tom - I suppose I wasn't clear at the beginning. It's not that I think the $125 cost is unfair, but it was high enough to push me over the edge to try something I've always wanted to be able to do.

I got partially done w/ #3 last night. My spacing isn't as good as #2 but I can't tell for sure that it's "off" without getting out the calipers, so it's close enough. Slots are angled towards the tuners, and I'm stopping at the 0.005 gauge. Still plenty low I think! I did get a little aggressive this time sanding down close to my pencil mark, so the top surface of the nut may not get a nice finish - we'll see.

[Tom Haywood]

I probably wasn't clear either. I'm really glad to see you undertake this project and that you've encountered quite a bit of the learning curve already. Looks like you are doing an excellent job! In many ways that is independent of costs.

Regarding string spacing, there are luthiers who eyeball that instead of measure. I've done it both ways. My preference is for careful measurements trying hard to get the first cut accurate, because I think it looks best. Free-handed doesn't look as good, but my hands don't notice any real playability differences unless the spacing is way off. Either way, I usually just go with whatever happened if it's close, figuring to replace the nut if it ever becomes a problem.

[Berto Boy]

Ira - I'll take it; thanks!

Tom - I suppose I wasn't clear at the beginning. It's not that I think the $125 cost is unfair, but it was high enough to push me over the edge to try something I've always wanted to be able to do.

I got partially done w/ #3 last night. My spacing isn't as good as #2 but I can't tell for sure that it's "off" without getting out the calipers, so it's close enough. Slots are angled towards the tuners, and I'm stopping at the 0.005 gauge. Still plenty low I think! I did get a little aggressive this time sanding down close to my pencil mark, so the top surface of the nut may not get a nice finish - we'll see.

I hate cutting mandolin nuts too. I've resorted to using feeler gauges to get the course spacing. I cut the two outside slots first, then select the feeler gauge that is 2 thousandths less than the slot and push it down into the slot to anchor it there. Then I use a combination of other feeler gauges adjacent to the anchored one that add up to the spacing I want and use them as a fence to run the slot file against as I start the next slot. It works well for me with my old eyes and hands.

[Melt_in_the_Sun]

I hate cutting mandolin nuts too. I've resorted to using feeler gauges to get the course spacing. I cut the two outside slots first, then select the feeler gauge that is 2 thousandths less than the slot and push it down into the slot to anchor it there. Then I use a combination of other feeler gauges adjacent to the anchored one that add up to the spacing I want and use them as a fence to run the slot file against as I start the next slot. It works well for me with my old eyes and hands.

That seems like a slick trick...anything to hold these squirmy files in place helps!

Back to the updates - i have a playable nut. I'd say it plays pretty well, spacing is good, edges feel nice. Strung the thing up with a new set of monels, so this is the first time I've really played it! Need to cut my fingernails and put a strap on it - it's more neck-heavy than I'm used to.

I give it a C+ on looks. I don't have a way to polish it, so it's just sanded w/ 320 and burnished with fine steel wool. Getting the slope back towards the tuners to look nice is harder than I thought. I'm afraid to sand too much lest I mess up the important bits.

So - it's worth doing yourself if you have some attention to detail and a bit of time on your hands. It probably took me 6 or 8 hours to get to this point, so I'm certainly not going into the setup business anytime soon. I will make one for my other mando though, since it's had a paper-shimmed half-broken plastic nut on it for 20 years now...

[rcc56]

You can sand as much as you want to with 320 dry, followed by 400 dry. Use only fresh, clean sandpaper. Then you can use some extra-fine polishing compound, followed by some white violin or guitar polish. I wouldn't use any more steel wool-- the bone can pick up metal fragments which will leave dark spots in the grain.

I clamp it carefully in a vise or lay it on a work board for final sanding/polishing.

[pops1]

3M scotchbrite comes in several grits and works like steel wool, without the shedding of the steel wool.

[Chris Pile]

Steel wool is THE DEVIL. It's magnetic, shorts out electronics, it rusts easily, it breaks down into little crumbs that contaminate a whole room.
Leave it for the cabinet makers. Scotchbrite comes in various grits, and isn't the catastrophe that steel wool is.

[Melt_in_the_Sun]

Looking with a loupe, my extra slot width on the Ds is clearly visible. I cut it with a 0.032 and the string is nominally 0.025. No issues - seems to work perfectly fine.

[CL Picks]

I stopped playing the rookie game a long time ago. I take it someone who knows what he's doing, which does not include me.

Scott

[Melt_in_the_Sun]

Over the last couple days I worked a little on my other mandolin. This one I tried something a little different - reduced the spacing of the pairs and moved the outer pairs toward the edge of the fretboard, giving a wider string spacing overall. Now my fretwear doesn't line up with the strings. New trick to get more life out of your frets!

This blank wanted to chip. Every time the large files bound in their slots a tiny bit, a little chip would fly free. I guess there's bound to be some variation in a natural material. I'm sure could use more practice keeping the files straight, but the previous three didn't do this.

Overall it worked well - still not a great looking finished shape. I cut this one a hair too low so shimmed it up with a piece of paper. I didn't want to start over given I wasn't sure if I would like the spacing. Turns out I like the spacing just fine, so I'll probably try to make a nicer one. The fresh white bone really stands out against the old binding.

[rcc56]

The deeper the slots, the more likely it is that a file will bind.
If I feel a file start to bind, I kiss the top of the slot with a miniature round file to knock off the sharp corners. Sometimes it only helps a little, but sometimes it helps a lot. And sometimes you get a lousy piece of bone. I find it's worth it to buy better quality stuff from a good supplier rather than the cheap stuff from AllParts or the like.

[pops1]

If the slot starts to bind I will start at the top of the slot and turn my file sideways and take a little off each side going down to almost the bottom. You can start the slot rocking the file, a little rocking of the file will help with binding so the slot is slightly wider than the file. I don't rock on the bottom unless I am using a smaller file than the diameter of the string.

[Melt_in_the_Sun]

Thanks to both of you! I do have a set of needle files so will try knocking the edges off the top. I have gotten better at keeping a slot clean by rocking all the files at least a little bit; the bigger ones are OK but the .013 and 0.017 will stick badly if I don't!

Getting these to look nice is really a bear - I tried this time! I need to thin the blank at the top surface for this mandolin; it looks like a giant buck tooth on there. Getting level exit points on the headstock side eludes me so far, even when I go back and revisit those slopes.

[Tom Haywood]

Enlarge the last couple of photos you took and look at where the break angle of each string occurs on the nut. It should be right at the front edge of the nut. That should be the high point of the slot. Place some painters tape on the head stock to protect from your file, then angle the file from the front edge of the nut at an angle slightly steeper than the string is. That will result in the string touching the nut only at the front edge and slightly into the slot. Level exit points at the head stock don't matter. Some folks like the string to lie on the bottom of the slot all the way down. To me, that leads to buzziness or muted sounding strings. I do a slight roll off of the slot so the string is above it most of the way.

Bone has a "grain" that can cause the file to bind while cutting slots, and can cause chip outs. I use a series of nut file sizes for each slot, starting with a .010 and working up to the string size or slightly larger.