Sharpening Used Files

A couple tips of acid etching. Not done files so can't comment on how well it will work.

Cleaning: you need to degrease the steel well. Oil will protect the steel from the acid making contact.

Heat the dip tank: acid works faster/aggressive at higher temps. Heating your dip solution to 100DegF will speed up the process.

Rinse in clean hot water: This allows the water residue to flash off. Then coat with a light anti corrosion oil for storage.
 
Yesterday I took a bunch of our used up Raker files and let them sit overnight in a plastic coffee can full of Oxalic acid. It actually worked pretty good. Not as sharp as new, but certainly usable. Neat trick.

8)
 
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  • #54
Good info, I was wondering if Oxalic might work. Good stuff for taking stains out of wood, and not otherwise altering the wood. Works real well if you have used metal clamps on wood and they have left stains when you wiped off the glue with water.
 
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  • #59
I use diamond hones on carbide. Taking out a chip might take a couple of weeks, though.
 
I'm reading here........and wondering if my carbides can be sharped with acid?

Short answer is no. When I was a dental lab tech I sharpened my burs with a semi flexible diamond disc. The best burs out there are made by Brassler spendy like $30-50 per large carbide but lasted a very long time I would guess about 100 hours from new till first touch up and maybe every 20-40 hours there after.
 
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  • #61
The test with the stronger vinegar came out with quite good results. The files that merely slid over the cutters now bite and sharpen. Worked on chainsaw files, flat raker files, and super good results on a wood rasp with the more protruding edges. An old German very good rasp that has been on my bench and held it's edges for many years, so very pleased to get it more useful again. The saw files aren't brand new again, but like Grendel said of his results with the Oxalic acid, certainly usable. 2/3 back to new? A very rounded over file that I had used for something else as well, didn't see so much improvement, but I am giving it some more time in the vinegar to see if it gets better. I'm also trying the Oxalic to see my results. Remains to be seen how long the resharpened files last, but they do sharpen up to usability considerably. Twenty hours was about my immersion time. Some mild surface rust after drying showed up, but I don't think it is a problem.
 
You motivated me to get some of my old files together.


I have been told the old files(probably '70s or maybe older, not sure exactly) will make a good knife blank. Kind of brittle I would think, but your not supposed to pry with a knife.
 
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  • #64
They also make woodturning tools. I have heard that too, that they are too hard and brittle, and probably compared to proper tooling are, but they work.
 
So, would muratic acid work better, with shorter soak times?


On the burrs. The plating in these cylinders is hell on burrs. I use the duller ones to cut thru the plated edges, then switch to a sharp one for the rest of the work. I'm paying 12.00 each for these......if they do a few jugs each, I'm ok.
 
So, would muratic acid work better, with shorter soak times?


On the burrs. The plating in these cylinders is hell on burrs. I use the duller ones to cut thru the plated edges, then switch to a sharp one for the rest of the work. I'm paying 12.00 each for these......if they do a few jugs each, I'm ok.

Muriatic/Hydrochloric acid should work faster, but is much more of a burn hazard than distilled vinegar. Plus disposal of the used acid becomes more of a problem.

An option on plated product is to use a stone to remove the plating then switch to the burrs.
 
They also make woodturning tools. I have heard that too, that they are too hard and brittle, and probably compared to proper tooling are, but they work.

Untill you get a good catch and it shatters in your hand.

Yes, I know you and I don't get catches while turning, but those with less practise do.;)
 
So, would muratic acid work better, with shorter soak times?


On the burrs. The plating in these cylinders is hell on burrs. I use the duller ones to cut thru the plated edges, then switch to a sharp one for the rest of the work. I'm paying 12.00 each for these......if they do a few jugs each, I'm ok.
Brassler makes all different kinds of burs some to cut gold and some that can cut titanium and chrome/cobalt alloys, much harder than a thin layer of chrome.
 
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  • #71
Data continues to come in and be run through highly advanced programs on the super computer.

Files that were used for other things than chains, and rounded over more that what you find on the average chain file that is deemed no longer useful, with an additional day in the vinegar, do get brought up to a degree of usefulness. After only one day was still mostly useless with those. I think the vinegar works better than acedic acid. As a general rule, 20-24 hours seems like a good amount of time for the files to get worked back to functionality by the vinegar. I'm totally confused by Magnus's method of only a few minutes in the vinegar, unless it is only removing oil. My drawer is getting a new supply of files. :)
 
Perhaps my apple cider vinegar act different. I tried other stuff but this was easiest.. If It sits too long it do more damage than good.
I dip clean files, really clean as no oil, dirt or such. This way it is just the files material that get treatment and thinnest part more than thickest.
It is hard to determine how long the various dirt take to go of otherwise. If it is packed in gullet the tip of tooth will go of before that is resolved and you end up with a dull file anyway.

If I have it in 15 min the surface is browned a bit. File is not improved as its edge is of, it feels smooth on surface. Will cut, but no good.
After 1hr the file is useless.
After a day you hardly feel the edges and liquid is darkened with lots of stuff in bottom of jug.
 
Did 24 rocked out harvester chains since first post in this thread using same two files.
Pfered 5,5mm for the Windsor B8 and Oregon 5,5mm for Oregon 18X. Both .404 2mm drivers 70DL

I do it faster and better by hand than grinder if it is not rocked, if so I think time is the same.
There is according to machine operator 20-50% more wood/chain cut from the chains I filed compared to those he has grinder by a pro grinder.
 
Oh, almost forgot, did 5 (4 rocked and one that hit box) 65DL Stihl harvester chains for hi yesterday with 5,5mm pfered file. Filed almost half tooth on a new chain one one of them.
 
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