File sharpening solution question.

[Bill White]

May have asked this before (not here), but I seem to remember that files can be re-pointed by soaking in an acid bath of some sort. Can't remember the type acid or the actual procedure. Any ideas?
Bill

[Brian Vaughn]

I've heard of using vinegar and battery acid (Sulphuric), although the time to accomplish the sharpening can vary wildly with those two. For the vinegar, you'd be looking at a couple of days, for the battery acid, depending on concentration, several minutes to several hours. Check google for "sharpen a file using acid" and it'll give you several good results that have procedures you could try.

[Chris Fournier]

I did this this summer. Do this outdoors, not in your shop as the fumes will create rust on all of your tools and equipment.

This technique will refurbish a tired file but it won't bring a clunker back from the dead.

[Bruce Wrenn]

This technique will refurbish a tired file but it won't bring a clunker back from the dead.No, but there are companies that resharpen files. Actually they recut the teeth.

[Larry Heflin]

You might want to take a look at Bob Rozaieski's video blog where he goes through the process of sharpening a rasp using vinegar.
http://www.blip.tv/file/4465081

[Dennis Puskar]

Larry very good video I'll have to try this.

[Dave Cav]

I have had good luck with battery acid, but it's not the safest thing in the world to be using in the shop. Next time I'll give the vinegar a try. It's cheaper, too.

[David Weaver]

Phosphoric acid has worked fine for me (sold as concrete etch in the paint section at the borg). Several people have told me they use citric acid. I've read several times old craftsmen peed in a jar and let it age (look up "lant") and then stored their files in it allowing the uric acid to slowly etch the surface of the files to keep them sharp.

I don't think the type of acid matters so much as knowing how fast it works and what you're looking to get out of it.

They are not like new out of the acid, though, and if you get them really dull, the acid won't be able to etch enough off to make them work nicely.

Boggs Tool does files (sharpening). I have seen several people say their files are sharper than new files after boggs refreshes them, and their rates for refreshing them are less than buying new on plain american files, and especially if you start getting into swiss files that can be $20-$30+ each.

[Jeffrey Makiel]

I've read several times old craftsmen peed in a jar and let it age (look up "lant") and then stored their files in it allowing the uric acid to slowly etch the surface of the files to keep them sharp.

I just recently got over a bad gout attach and now take medication to reduce my uric acid. Had I known, I would have peed on my files while the throbbing in my big toe subsided.
Jeff :)

[Jon Endres]

I've sent several dozen files to Boggs Tool in California, and they have come back better than new. Nearly all have been old Nicholson files, some 40-50 years old and covered in rust. The worst ones, they will clean but will paint the tang red and send them back to you unsharpened. They decide what's junk and what's salvageable. I saved a dozen old Vixen files (curved tooth autobody files) and they are ideal for end grain and clean cuts in wood.

[Lee Schierer]

Just a dumb question. If you submerge the file in acid, won't all the surfaces be attacked equally? If a file tooth is rounded over why would the acid tend to make it sharp?

[Brian Vaughn]

You're right, they will be attacked somewhat equally, however if you think about the surface of a file, it starts as VVVVVVV Then once dull, more like UUUUUUU. If you attack both sides of the tooth equally, the surface will be eroded perpendicular to both faces. The reaction is that the tooth will narrow, which will also decrease the height, increase the width of the valley, but leave a sharper tooth.

*I don't know why it says "attack" twice, I've tried to delete it several times

[Floyd Mah]

An old fashioned trick is to pick up your file, go to the back door of your house, open the door, toss the file into the bushes, wait a few days, retrieve the file, use a wire brush to scrape the rust and your file is now sharp. Really. Never tried it, but it's supposed to work. Now ask me about using a potato to clean rust.

[Zane Moseley]

I work in a large cabinet shop specializing in laminated cabinetry and there is a lot of filing involved. Recently we have started soaking our files in a vinegar bath with wonderful results. I work in engineering so don't have a lot of hands on experience with the files before and after the soak but have heard good things.

[Gary Curtis]

Send your files to Boggs Tools : 14100 Orange Avenue Paramount, CA 90723-2019
(562) 634-1081

My dad was a machinist and left me a lot of gorgeous files. I live in Los Angeles, so I drove the short distance to Paramount with the old files. They sent them back to me by UPS in a week. You would have to see their operation to belief it. They blast the files from the side with steam carrying an abrasive powder. It cuts and deepens the teeth. The large rasps came back so sharp I cut my fingers examining them.

Now that is sharp! Something you won't get with battery acid solutions. And at only a buck or so per file.

[Rick Moyer]

I've read several times old craftsmen peed in a jar and let it age (look up "lant") and then stored their files in it allowing the uric acid to slowly etch the surface of the files to keep them sharp.


David, put down the mouse and slowly walk away from Google. I think you may be internet surfing too much.:D

Although I suppose that would be good to have around if one would happen to also have jellyfish in the shop.

[george wilson]

I have sharpened needle files by reverse electroplating them in a bath of sulfuric mixed with nitric acid. This peels metal off the surface of the files more quickly than just acid etching.

[David Weaver]

george...of all of the people in the world who have plenty of needle files and would never need to sharpen them again...your stash will rust before you get to it!

[David Weaver]

David, put down the mouse and slowly walk away from Google. I think you may be internet surfing too much.:D

Although I suppose that would be good to have around if one would happen to also have jellyfish in the shop.

Actually, a machinist on another forum used the word "lant" as a way to store files and keep them sharp, and I had to look it up. I didn't even have to go looking for trouble to find that one, someone else brought it up :)

(I didn't try it........but noticed when I looked up the word, wiki was one of the top entries, and apparently it's been used as medicine, an additive to beer (single lant or double lant) and brushed on bread before baking.....can you believe that? I think I recall something about towns being called to increase production as a collective effort when there was illness! Normally I wouldn't remember something so well, but when something is that odd...you remember it. I think tobacco enema was somehow linked to that article. Makes you glad to live in the era of modern medicine!)