learned some time back not to drag the file backwards.?ÿ Didn't know if this was common knowledge.
It's only a file, and you can always buy more.?ÿ Is it common knowledge ?
A quick search shows that this advice is commonly given, even by sites like Popular Mechanics, but that a lot of expert machinists say that you only need to take the pressure off the file on the back stroke, not necessarily lift it.
https://bbs.homeshopmachinist.net/forum/general/69429-file-question#post1445722
I have a file that I must have bought in the 1970's or 1980's and have used a lot, that is starting to get a bit dull.?ÿ I always take the pressure off but don't worry about whether I lift it.
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I always take the pressure off but don't worry about whether I lift it.
I usually lift it on the backstroke, but I'm not obsessive about it.?ÿ As long as I don't have pressure on the backstroke I'm happy.
It's to do with heat. Lifting or depressurizing the file on the backstroke provides cooling to the faying surfaces, thus reducing the possibility of heat damage.
I don't think I can produce metallurgically significant temperatures by hand filing.
Actually it more about the rasp and not the file. Dragging a rasp backwards is not recommended. Rasps for wood and horse hoofs, files for metal and wood, I once bought a rasp to file down rods thinking it would go quicker, not a good tool for that. And dragging it backwards didn't work anyway.?ÿ
I don't think I can produce metallurgically significant temperatures by hand filing.
Likely not in the workpiece or even the file overall, but at the cutting edges I think it's possible, and that's where excessive heat buildup can be a problem.?ÿ I'm not sure that's a *likely* case with hand filing, just that it could be an issue under the right circumstances.
It's all about heat transfer.?ÿ "Speeds and feeds" is the mantra for work on a metal lathe.?ÿ Even though the cutting bit is relatively small (sometimes tiny), if you get the rotational speed and longitudinal feed rate right you can have blue-hot chips coming off the workpiece while maintaining a low bit temperature, even without running coolant.
A file, like all cutting tools, is just a collection of cutting bits, so the same applies.
I don't know just exactly how damaging it is, but my 8th grade metal shop teacher certainly insisted that it was a mortal sin.?ÿ
@rankin-file
Mr. File has told us about various family members over the years, but I do not recall any of them being named Metal File.?ÿ I'm confused.
Maybe Metal File is the one no one in the family talks about because he, you know, got dragged backwards.
I'm the idiot. I pictured a 4 drawer metal file cabinet being "dragged backwards" and was contemplating if that meant all of the drawers were facing downwards and opening up. Then the revelation of OH! that kind of file.
I'm the idiot. I pictured a 4 drawer metal file cabinet being "dragged backwards" and was contemplating if that meant all of the drawers were facing downwards and opening up.
If it makes you feel any better, I once bought a large flat-file cabinet, loaded it in the back of my truck, and headed home.?ÿ At the first left turn the top drawer flew out and landed in the intersection of a very busy street.?ÿ I had to go around the block in order to retrieve it, but by the time I got there it was gone.
FWIW, when we were taught filing at metalwork class at high school, we were instructed to chalk the file, which I think had something to do with reducing the amount of filings clogging the file.
