How To Sharpen Mill Files And Rasps

[cabinetman]

I use mill files on wood, plastic laminate, veneers and metal laminates. File cards and stiff brushes are the common methods for cleaning files but in no way will they sharpen them.

After I had a stash of a coupla dozen I had a brainstorm of cleaning them in a bath of muriatic acid (just the ordinary pool type). I used a plastic tray with sides, and set the files in on edge and let 'em soak. Well, when I finally pulled them out, they were clean alright, and were sharper.

I must say that this is an incredibly hazardous method, as the acids emits toxic fumes and more so when the acid was added to the files. If tried it should be done outside, away from the house or shop. Appropriate gloves, arm and face protection should be used. Proper disposal of the used bath should taken as with any hazardous material.

It won't make them like new, but will give some new life.
.

[docrowan]

I've read about this method of sharpening files, but have never tried it myself. Good to know it works.

[jackellis]

How about trying household vinegar. Much weaker acid but at that concentration it's not toxic and I don't feel guilty about tossing it down the drain when I'm through.

[cgallery]

I can't underline the importance of keeping muriatic acid away from the shop and home. The fumes "have feet" and will land on and rust your tools, furnace, etc.

When you're done w/ MA, you can dump baking soda into it until foaming stops. Once adding baking soda causes no more foaming, the acid can be disposed of safely.

[ironhat]

Are you saying that the MA is undiluted for this purpose? I've got 3/ of a gallon and about 8 nearly dead files to try this on. Let's see, how's Saturday...?

[crokett]

Another use for MA. Who knew? I use it in my pool to bring the pH down.

[tfm37]

If tried it should be done outside, away from the house or shop. .

Don't even think about storing a bottle of muratic acid in your shop,even if you have sealed it well. It will emit enough fumes to corrode any machined steel surface.

[sd]

Somewhere in another forum or newsgroup I read about a company that sharpens files using a liquid honing process. Googling turns up Boggs Tool and File Sharpening Company. I have not used their services myself, but they might be worth looking into if you've got a lot of files that need sharpening.