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I've got a couple of sets of nut files that span the usual range of gauges on acoustic and baritones. They've served me well on the bone nuts for my own guitars, but more and more they're being used for work on client guitars running through my repair business. I find that some synthetic nut materials and especially CA used as slot filler clogs the files. It's especially noticeable on the smaller gauges that seem to lose their bite entirely.
I've tried soaking in acetone, but wonder what secrets the full-time repair guys can share for keeping their nut files cutting properly?
Maybe it's simply time to replace some files.


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I take it rubbing them across a regular brass file brush doesn't do the trick?

I have a normal old file card, and a small brass brush I got from StewMac. When all else fails, soak the file in dilute muriatic acid to remove or loosen tough to remove materials. Neutralize in water mixed with baking soda. Suggest you brush up on safety rules before using this stuff. It can be evil.

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"Act your age, not your shoe size" - Prince

My files get a lot of use often three or more times a day for years. As such I replace some of the more common ones every couple of years but I save the old ones and mark then as "OF" with a Sharpie. The older ones are great for when you need one last swipe and if you press too hard you blow the nut. With an older file that one last swipe rarely becomes get the composite dental fillings kit and UV light out....

Recently I used my miniature brass file brush that IIRC originally came from LMI over a decade ago. It cleaned the clogged files that were clogged with dental filling material very nicely and some of my "OF" files were to my surprise nearly as good as the newer ones. Go figure.

There were recent threads on FRETS and IIRC here too on this subject and some other tricks such as leaving them in the yard to rust on purpose and sending them out to someone for a chemical treatment that sharpens files.

I have not tried this, but... When filing aluminium I first put some chalk on the file. It stops the Al from clogging the file. May work for you.

Jim

Interesting idea. Certainly aluminum makes a quick mess of files.


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Pickled files -- I like it!

Gonna have to spend some time with my file brush, but I suspect my smallest files are likely beyond their best performance no matter what.

Thanks for all the ideas, guys!



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Another good tip is graphite/pencil lead rubbed on the file to lubricate the cut. Works wonders.

I have used the chalk-before-filing method with great success, but for a bone nut a file card usually does it. As for the muriatic acid trick, I have done this several times (last time 10 days ago). You have to clean the gunk off before you immerse the file because the gunk will inhibit the acid and make for a weird tooth. Also, because you are eating away at the metal, a nut file will no longer be the right size. With these small teeth, try it for an hour with acid right out of the jug. For conventional sized files, it may take a few hours - set a timer because it is easy to loose track and you will ruin the file (DAMHIKT). I know you are supposed to neutralize the acid, but half the time I just rinse them and then soak them in fresh water and dry them with paper towels

Here is my rig - card file, brass brush, glass vase, wooden block to keep vase upright (DAMHIKT), and acid. This file has 9" of teeth. For longer files, I use a heavy plastic tupperware type thingy.

The best part of this is you can buy old files of particularly interesting and expensive shapes and styles and bring them back to near-new. I rarely pay more than 25-50 cents for a file

Good luck, and be careful out there

Ed

Have used the chalk for 36 yrs! and also I use vinegar which cleans and dissolves the glue/guk crud. on files . This changes the files color.It turns the glue runny which is washed off, and then a file card or brass bristle brush from HF. I use vinegar a lot for cleaning glue brushes, and recycle the wifes old plastic trays. The glue sits on the bottom after 1 day. We use 5% acetic vinegar

I use CMT Formula 2050. It is for router bits, but it cleans files, blades, drill bits and I was shown that it even cleans sanding discs by a luthier I know. He cleans drum sander belts and reckons they last a lot longer. This stuff and a toothbrush do a great job on files