Official Luthiers Forum!

Does anyone know where I can get a set of these nut slot cutting tools? I purchased these several years ago (eBay?) and have used them to make well over 100 nuts. I use them with cutting fluid but they are starting to show their age.

I appreciate any contact information regarding the manufacturer.

Mike Franks
http://www.mjfranksguitars.com

Look like Norman's Nut files.
He has stopped selling them as I understand. He still has an ebay account under "norman_1957", but hasn't sold them for a while.
Have you tried sharpening them? Maybe a small saw file would work, or a diamond feather file.
I hope so, I have a set. and know they will blunt eventually.
I know they have not been so popular, but I have had reasonable success with them.

_________________
The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Norman was a total Ebay legend ...we shall not look upon his like again ...

those look suspiciously like lengths of hacksaw blades that have been milled thin

"those look suspiciously like lengths of hacksaw blades that have been milled thin"

Now that's a thought! I wonder what would be the best way to do that?

Actually they were feeler gauges with teeth cut in them. That is if these are the Norman files? I thought they were junk and quickly re-ebayed mine. If you need cutting fluid to cut nut slots something's wrong.

_________________
Another day, another dollar.

The nut files appear to be made from feeler gauges which have a radiused edge and teeth cut in them. They show the mark of flame hardening along the teeth.

To be clear, I never said that I NEEDED to use cutting fluid, I CHOOSE to use cutting fluid because it prevents loading of the slot and subsequent chipping of bone or ivory. As I mentioned in my previous post, I have cut over 100 hard bone and fossil ivory nuts and the cutters are still sharp enough to do the job. I wonder if Shaw got a set that were not hardened properly.

Mike Franks
www.mjfranksguitars.com

Frank, yours look the same as mine, heat treated.
May I ask what you use for lub?

_________________
The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Colin, I use a water-based tool cutting fluid. Liquid detergent works also to keep the file from binding. I shy away from oil based lubricants due to the porosity of bone. I don't want an oil soaked nut which may not stay glued.

Any acid will sharpen the teeth of a file. I use the muriatic acid that the mason left behind a few years ago. I find that for finer files, a couple of hours is all it takes, so for this small file you might try 30 minutes, rinse it off, then give it a try. A friend uses citric acid and it takes overnight, so is much more controllable.

And these people will do it for you for about $2 a file:

http://www.boggstool.com/

I have put about 8 files in a flat rate USPS Priority Envelope, but yours would fit in an envelope.

Ed Minch

Hey Mike, I don't come 'round here often these days, but for you...

I'm not a fan of that style of cutter. No angle behind the face to actually create a proper cutting edge, sub-standard materials to qualify as a file, and quite frankly, lots of far better alternatives for extremely reasonable prices. Here's a post from another forum where I went I to more detail a few years ago -

http://www.tdpri.com/forum/tele-technic ... ost2477598

I have some Grobet files that I've put through over 20 years of full time use, thousands of slots behind them on bone, synthetics, brass, aluminum, and steel, and are still going strong. The current StewMac files come in as a surprisingly close second to me, good steel, good cutting shape, and quite cheap in a wide selection of sizes. If you don't cut slots every single day, they will last you a lifetime and will prove a purchase you'll never regret. If you are cutting with them every day, then you might need two sets. File life should be measured in thousands of cuts or more, not tens or hundreds.

_________________
Eschew obfuscation, espouse elucidation.

David, Thanks for the info. I remember seeing your collection of nut files and being quite impressed. I'm going to upgrade my set of files to some Grobets.

Hey, Dave. Good to see you on the forum! Are you referring to the Stew Mac "Gauged" nut slotting files? I have a set of double-edge files I got from some years back and have never been real happy with them.

_________________
Max Bishop
Brighton, Michigan

One fine Grobet round needle file. That's all that I use. I ground the teeth off two opposite edges, so it works a little like joint file but it's tapered - a little like the LMI Pippin file. You don't really need to grind the teeth off though. Once you get your eye in any string gauge is possible. Using just one needle file is actually MUCH easier than many folk think if you follow the rule of half (or a touch over) string depth. I see far too many top nuts where the strings are buried in the slot.
The LMI Pippin file. Now that is a poor choice for nut slots.

Michael, could you perhaps elaborate on why your DIY grind on a Grobet needle file results in a superior tool to the LMI Pippin file ?

It's simply not very good for doing thin strings. The edges are a little too rounded (fat?) for thin gauge strings. I also don't think that the cut is as fine as those found on a Grobet needle file. In fact I'm quite sure it isn't. My Grobet file is a delicate tool and finishes at a very fine point, in comparison the LMI Pippin file seems much clumsier. Might be good for doing bass strings. Bass as in double bass.
There are other Pippin files. Some on UK ebay that are NOS - supposedly very good quality although I've not tried them.

Are Grobet files gaged? Where are they available?

Very interesting, Michael. Thanks for your post.

Could you elaborate on your techniques.
- How do you do .010" up to .056" slots with one file size?
- do you measure the slot width you are cutting?
- what accuracy to you target (i.e. how much bigger is the slot than the string)?
- do you have a link to the actual Grobet file you use?

The thinnest string that I do is 0.4 mm's - which I think is a little larger than 0.10". In any case it's still possible to do very thin steel strings because most Violin repairers use a single needle file. With a string as thin as that you hardly do anything to the top Nut, a few strokes with the file. It just has to sit in there, sufficient so that it doesn't pop out under playing.
I can't give you a link to my needle file. I've had it so long I can't remember where I bought it. All I know is that it's a Vallorbe/Grobet (Swiss) and it comes to a very fine point. It's just a good quality needle file but nothing special about it. You have to be extremely careful when using it at the pointed end. It's very easy to break the point, which is why I ground the sides of one! A round needle file is tapered, that's what allows you to do different gauges with one file. I don't measure anything. I place marks on the top Nut, just a nick with a fine zona saw. Strings are put on, I judge everything by eye but also by pushing the string across into the slot. I just do it until it looks right. I have a tapered piece of wood that has a few pencil marks on it. That is pushed under the string, above the fretboard (right next to the Nut) and it sets the depth or the action at the Nut end. I made a few of those for different height frets.

One source is http://www.ottofrei.com/Joint-Round-Edge-Hand-Files/

_________________
The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Great! Thanks much, Colin. There are lots of good size choices there.