1926 file facts:

[sasquatch]

Last night while reading through my old "American Machinist Handbook" By "Colvin and Stanley" -1926 -i came across an article about "When a file cuts Best."
Quote:

One who has given the matter carefull attention, and has built file testing machines, "Edward G. Herbert" of Manchester England, has come to the conclusion that a file does not cut best when it is new, but after it has been used for a time, say 2500 strokes or the filing away of one cubic inch of metal.

In cutting a file, the metal is forced up in a sort of a burr, and occaisionally the top of the tooth slopes over backward which is the reasonthat a file often cuts better after these are broken or worn off. Too the teeth are not all the same height, and only a few points cut. As they wear down, more teeth come into contact and do more work.

Opinions IF this applies to todays files??

[aboard_epsilon]

think there is a guy on here from france ..who makes files ..he will give you the best answer .

all the best.markj

[boslab]

think there is a guy on here from france ..who makes files ..he will give you the best answer .

all the best.markj

andhis file shop vidio is brilliant!
i dont think that the contention of tooth height is relavent today as files are reasonably consistant, i have found that chemically resharpened files are better than new ones, i think that the etch intriduces irregularities like waviness that you find on a serrated knife, but that is only my theory.
mark

[lynnl]

... i have found that chemically resharpened files are better than new ones, ...mark

Chemically resharpened?? How's that work?

Is that just a brief acid dip, or something?

I've wondered about electrolysis (rust) treatment, and if that wouldn't tend to resharpen a file.

[sasquatch]

Lynnl somewere i think back awhile there was a discussion here or on another forum concerning sharpening a file in this way.

[metalmagpie]

I know that wafer probes (really really sharp needle-like contacts they probe right onto integrated circuits with, using a microscope) are sharpened using an acid dip. They are placed into a machine that dips them slowly in and out of the acid. The tips spend more time submerged hence are eaten away more.

[Lew Hartswick]

I know that wafer probes (really really sharp needle-like contacts they probe right onto integrated circuits with, using a microscope) are sharpened using an acid dip. They are placed into a machine that dips them slowly in and out of the acid. The tips spend more time submerged hence are eaten away more.

Yep. That is way some prof at Penn State got a point so sharp that
by using some field technique he could actually see individual atoms.
That was back in the 60s I believe. Forget his name but it was a big
thing back then.
...Lew...

[gwilson]

Nicholson triangular files were advertised as being "increment cut",so the teeth were varied in height,and new teeth would cut as the old ones wore down. I'm dubious as to how practical the concept was,though. You'd be trying to force the duller teeth into the metal while trying to bring the sharp teeth down to cut,once the higher teeth wore down to the level of the lower teeth.