Sharpening files.

[Buchanan]

Has any body first hand experience in resharpening files with battery acid or by means of electrolysis. I have a large number of very good quality fine second cut files that have lost their edge and do not cut brass any more. I would like to resurrect them if at all passable. You can see what I use them on at http://www.my-time-machines.net/my_current_project3.htm I originally used hardened filing buttons and this caused most of the trouble.Now I never harden a filing button, I just make them real long and they last plenty long enough but my files are blunt.
Thanks.
Buchanan

 

[Swifty]

that's truly amazing work, do you make every single part yourself? How long to make one clock?

Paul.

 

[goldstar31]

I recall that there was a lot of correspondence in the past in Model Engineer.
As far as I can see it, electrolysis will do two things. One is to properly clean clogging and the second is to slightly sharpen the teeth.
Obviously, the only way to create or recondition cutting tools is to mechanically do it as chemical treatment is pretty ineffective.

I hope that this helps to discourage old wives' tales.

Regards

Norman

 

[Buchanan]

Paul initial correspondence started in 03, and construction proper 07, there are a few more years to go.
Gold star. I remember it coming up in Model Engineer but wondered is there have been any recent progress or experience. I tried it once many years ago in battery acid but it attacked only sections, which I put down to oiliness.

 

[goldstar31]

Paul initial correspondence started in 03, and construction proper 07, there are a few more years to go.
Gold star. I remember it coming up in Model Engineer but wondered is there have been any recent progress or experience. I tried it once many years ago in battery acid but it attacked only sections, which I put down to oiliness.

Whilst something like a boil in a strong caustic soda solution will remove fats, plastics( and your mother in law) etc, sticking the files in dilute sulphuric acid will give no better results than expecting a similar treatment of lathe tools left to 'sharpen'

So one simply employs a wallet spanner to provide sharper equipment-:hDe:
Sorry but nevertheless true

Norman

 

[Tin Falcon]

BOGGS tool in Paramount CA will sharpen files. from $).50 for a 4" flat file to $5.00 for a horse rasp. most files $1-2 each. IIRC fist time customers could send a file in for a free trial .
http://www.boggstool.com/page74.html
tin

 

[Brian Rupnow]

I didn't know that files could be sharpened!!

 

[t.l.a.r. eng]

Overheard an older machinist talking once, told another guy to throw the file out in the weather for a year or so. Didn't know if he was kidding or serious.

Turns out I had a chance to find a couple of files left out in the rain for a couple of years, and while it is true the files were sharp, they couldn't be guaranteed to cut flat or smoothly.

 

[velocette]

Hi Buchanan
Yes This is possible with electrolysis.
Use a plastic bucket and a solution of "Washing Soda" and a Battery charger.

Full Details on the method is here

http://antique-engines.com/electrol.asp

IMPORTANT!!!!
To "Sharpen" your files you must Have the file connected to the Positive + lead on the power supply to erode metal from the file.
The time it will take can best be determined by monitoring progress every couple of hours as the area of the file and the electrode combined with the amount of current from the power supply.
The results can vary depending on the condition of the file.
You should have a file that will remove metal again though sometimes not as well a brand new file.
BE Aware that Hydrogen Gas is produced by this process so adequate ventilation is essential.

Eric

 

[Buchanan]

Thank you everybody for your input. Eric ,I will have a look at that that website.

My files are mostly old high quality Valorbe and Grobet Swiss or Bedford English. They have given years of good service but have lost that beautiful new file sharp feel while they cut fine on steel. Give us a while and I will post the results.

Buchanan

 

[barnesrickw]

So using a file card is not good enough? I know at some point they just wear out, but I've had good luck file carding them thus far.

 

[Buchanan]

Barnesrikw
Yes I do clean my files and this helps when the teeth get clogged, but I need real sharp files as the material I file mostly is brass and it is often very delicate . I cannot just push harder as the part will bend. Have a look at the website in my first post and you will see what I mean.

 

[bazmak]

A file card or wire brush only cleans the files.But from experience i do know
that dipping them in water and letting them rust a no of times over a few days
with a good wire brush daily to remove the rust does improve the sharpness
But at the end of the day i would suggest buying some new files and restrict their use to important jobs and using your old files for general rough work
I use the same principle for my drills etc.Keep the best set for important drilling and use old drills for step drilling and general use etc

 

[imagineering]

There is a Business in Wellington, New Zealand who does just that. "Filesaver' is the name of the Company. When I had a chat with the Owner, he said that he uses Nitric Acid, and gets 3 Lives from every File before discarding them. I purchased a couple of 18" Files from him and found them to be as sharp as new.

 

[Buchanan]

Here is a photo through a microscope of the wear on the teeth of one of my files. You should be able to see them as small diamond shaped flats. I will show an 'after' photo when I have made an attempt at sharpening. They show better in the original photo on my computer so I will take one at a larger magnification.
This file has about 80 cuts per inch.

 

[goldstar31]

I came across an article by Barry in Model Engineer. My old but very incomplete records.
2 pages with the need for 1000 amps and 50volts.

Won't do Vallorbe and such files- or so its says.

Drop me your E-mail address if you want a copy.

Regards

Norman

 

[Buchanan]

Norman.

Thank you very much for the Model Engineer article. I have many Model Engineer but no as old as this article, mine go back to the early 70’s

From the article it seems that the amps make things go faster, 100 amps per file for fast sharpening. Swiss files often break teeth as they are so brittle and this seems why he says that they will not sharpen. The degreasing is vital as well as the rust prevention afterwards.

I will start to accumulate the necessary chemicals, I have a good power supply.
Thanks.

 

[David Merrill]

https://www.google.com/webhp?complete=0&hl=en#complete=0&hl=en&q=sharpening+files+acid

David Merrill

 

[velocette]

Hi
be careful 100 amps and 50 volts will boil a few litres of the solution in a very short time.

Eric

 

[Buchanan]

Yes Eric that is 5 kw! They have lead cooling pipes and it is an industrial environment where through put is everything. i will be monitoring every thing carefully and taking it slowly. Especially as most of my files are very fine cut.
Thanks.

Buchanan