Sharpening or restoring dulled nut files?

[Mike Kolb]

I've built a sizable collection of nut files over the years...  sometimes shuddering to think what the total investment has been, and that's what leads me to my question.

An increasing number of the oft-used ones have, over time, dulled.  I've already gone the route of breaking-off the ends to present a fresher surface area, but that can only be done so often.

Curious if anyone has experience with acid-sharpening nut files?  If so, what sort of acid and at what strength?  I'd also imagine there must be an optimum length of time for sharpening without causing irreversible damage.

Or maybe I'm hoping for a magic fix that ain't there?!  Curious about all comments... thanks. 

[Mike Kolb]

Hey... where'd my thread go?!  :)

[Steve Williams]

aluminium files mike

[Mike Kolb]

Ha.... good one!  Alchemy at it's finest. 

[Ned Knepp]

Sorry Mike, I got carried away... again. 

Cleaning out some old chemicals as part of a planned trip to our local hazardous waste facility, I found some muratic acid  that I thought was long disposed of. I may have some old dull files around to try if I get a chance in the next couple of days. It would have been gone but some yahoo cut the catalytic converter out of my truck a couple of nights ago and I'm still sorting out the insurance claim.  

[Mark A. Kane]

I'll report back on my results as I've just shipped 4 Stew Mac tapered nut slotting files to Boggs for sharpening.

[Mark A. Kane]

I received my files back from Boggs (took about 2 weeks) and am happy to report they cut at least as well if not better than when the files were new. They are now marginally narrower, as material was necessarily removed in the process, but cut like a hot knife through butter. I found that now I have 16 different slot sizes to choose from, so to speak! But I really do have to watch the depth closely, as these cut through bone very aggressively. The cost was less than $20 shipped, so it was absolutely well worth the trouble!

[Mike Kolb]

An excellent report, Mark!  So the cost ran about $5 per file?   Well, based on this, I'm going to send a few dull files off to Boggs and get the set back up to snuff again!

Thanks for posting the results :)

[David Farmer]

Thanks Mark.

I have some old files that were dogs out of the box. Seems like Stew Mac files used to be hit or miss. The newer ones seem to all have good,"bite".

I could never bring myself to just pitch the bad ones. Now I know what to do with them.

[Mark A. Kane]

Upon reflection, my Stew Mac files never cut as well as these sharpened files from Boggs. I may send off the newer set as well sooner rather than later.

[Ed Minch]

Mark

Great to know.  Thanks for the report

Ed Minch