Annealing a file.

Gliden07

Gliden07

Well-Known Member
How hot do I need to get a file to anneal it? After heating I was told to cover file with Vermiculite till cool. Or if someone in the KD family has a better way please
 
General rule of thumb with carbon steels is to heat to non magnetic, (have a magnet handy & test) and slightly beyond, then cool down slowly. I have just left it by itself in normal room temperature, but your procedure of placing in vermiculite or dry sand or a similar insulating material works very well.
 
Walter Sorrels suggest leaving it in a bucket of sand after the heat treat. Check out his videos, they are very informative. I also have read that you need to stick with quality files like Nicholson files.
 
Depends on why you need to anneal it. If you just want it soft enough to drill a few holes, heat 2 or 3 times to a low red heat letting it air cool between heats. If you want a machinable anneal, heat to between 1275° and 1290°, hold for an hour, then let cool about 50° per hour until it gets under 900°. Then let air cool. A good file will be a hypereutectic steel. You do not want to use a standard anneal, if you want it really soft.
 
I want to make a knife out of them. I like the look of the Ferriers file knifes, plus I figured it would be a good way to practice cutting bevels on my 1x30 HF grinder. Figured I could pick beat files at tag sales or flea markets cheap to practice on. Hopefully make a useful knife out of one or 2 of them?
 
I like the ferries files too! I think files make an interesting knife texture if just a small bit of the pattern is left on the flats.
 
opaul said:
Walter Sorrels suggest leaving it in a bucket of sand after the heat treat. Check out his videos, they are very informative. I also have read that you need to stick with quality files like Nicholson files.
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Yeah I like Walter. I will look for that video. Sands is way cheaper than Vermiculite! I may even have some play sand around somewhere!
 
That's "farrier" gents.
A farrier is a specialist in equine hoof care, including the trimming and balancing of horses' hooves and the placing of shoes on their hooves, if necessary.
If you are going to use stock removal, you might want to stay with regular files. Grinding the teeth down on a rasp will wear out sanding belts pretty quick even if they are annealed. All those teeth add up to a lot of steel to grind.‎
 
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Just a word of caution when it comes to using "old files"..... these days many files are NOT made of high carbon steel.....but rather of a cheaper grade/low carbon steel and are Case Hardened. What that means is that many files only have a hard "skin" of .005-.015" or so. In many cases you can go to all the effort of creating a blade from a file, and then it simply will not harden. I would suggest making sure the material will actually harden before putting all that time/effort into it.
 
LRB said:
Depends on why you need to anneal it. If you just want it soft enough to drill a few holes, heat 2 or 3 times to a low red heat letting it air cool between heats. If you want a machinable anneal, heat to between 1275° and 1290°, hold for an hour, then let cool about 50° per hour until it gets under 900°. Then let air cool. A good file will be a hypereutectic steel. You do not want to use a standard anneal, if you want it really soft.
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Hypereutectic! That is a big word that I did not know and had to go look up. Perhaps you can explain the implication of that term please, because it seems to implicate complicated annealing and hardening.
 
Sorry. Hypereutectic is a steel with more than .77 /.8 % carbon. Iron will only absorb that amount into a homogenous solution. Hypoeutectic steel has less than .8% carbon. Any extra carbon is in the form of carbides and will be distributed about as sort of free agents. When steel is slow annealed as in a common anneal, a lamellar structure is created. Basically layers of iron/ferrite, with layers of cementite/carbon. These layers in steel with less than .8% carbon will easily allow tooling to cut the steel. In steels with more than .8% carbon, the cementite/carbon layers will be thicker and more resistant to tool cutting. To be softer, hypereutectic steel needs a spheroidized anneal, in which the carbon forms into spheres rather than layers. This done by heating to above 1333° and somewhere under 1414° which is the temp that steel loses it's magnetic attraction. Say around 1375° and hold there at least a few minutes, then cool at about 50° per hour until under 900°, then let air cool to ambient. If you have no way of controlling temp, just give the steel multiple heats that are just under non-magnetic and let air cool. You can slowly bring a piece of scrap steel to non-magnetic and take note of the heat color, then do the annealing heats at less than that. This is not a perfect explanation of it all, but close enough I think. As I mentioned though, a few red heats on the file, with air cooling, always got me by. Not the best way, but made the files reasonably workable.
 
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