Use of chalk with files

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    Julio T.

    Hello all.

    I’ve read somewhere that if you put chalk on the surface of files you can obtain a better finish on filed surfaces. I’ve read that it only works with single-cut files, not with double-cut files.

    Has anybody used chalk when filing, specially when sharpening? I haven’t been able to find it, but I remember a text where it was recommended using chalk on the final pass of file when sharpening a saw, in order to obtain the best finish in teeth surface. I always could try, but I would thank some first-hand information. I wouldn’t like to ruin a good file or a good saw, and I can’t help but thinking that if chalk it is so good when filing we haven’t seen Paul talking about it…

    Thank you in advance.


    Not just ‘Chalk’……’Chalk’ is Calcium Carbonate- a form of Limestone. Useless on files.

    For saw-files, you need what is termed, ‘French Chalk’ or Magnesium Silicate…………. basically, it’s refined talcum powder – without the perfume.

    French chalk, when used with files, holds and suspends the micro-particles of metal, allowing them to fall away in the powder without jamming the cutting edges of the file stitching – thereby prolonging the edge sharpness and the life of the file…… some folk use it, some folk don’t.

    Julio T.

    Thanks for the answer. I didn’t know that it was another kind of chalk.


    It is ‘Chalk’, (French Chalk) in name only….. Talcum, is a different mineral entirely.

    I’ve never used it on saw files, but I’m told that it improves the action, reduces vibration and aids clearance of filings. You do end up with a lot of powder all over the work!

    Good luck

    Larry Geib

    Just to confuse further, talc, or talcum, is Magnesium silicate.
    Blackboard chalk is calcium sulphate dihydrate, or gypsum, not a carbonate. And that’s what I’ve seen metal workers use.
    It comes in fatter sticks as industrial chalk and tinted for kid to play on sidewalks. They are water soluble, and even comes as a liquid marker.

    The base for Sheetrock is also gypsum.

    • This reply was modified 2 years, 5 months ago by Larry Geib.
    Caio Rosa

    You most certainly will not be ruining a file with chalk, either being either gypsum or talc. It may work as a dissecant to keep the files safer from air moisture, but the thing you’ll really notice is the effect it has as a lubricant. It makes the initial passes a lot easier, and it does smooth the action of the file, which could to a certain extent give a better finish – steadier, straighter and easier to control strokes, less vibration, less screeching hair-erecting high pitched noises. We absolutely underestimate how making something less unpleasant to do effects positively in the results. We dont rush as much to finish it, so we do it better, for as longer if necessary, we dont avoid doing it when needed, and the “good enough” mark goes up quite a bit.

    On a note, thats why I hate turning on machines. Need to setup dust collection, push stuff around, wear safety equip. I just want to finish the process im on as quickly as possible so I can claim my shop floorspace back. Then, I get bad results from the resawing, or thicknessing I was on. Which makes me dread the next time when ill need to it again.

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