Safe edge on a file

[tom in nc]

I just bought a bunch(15-18) of good looking old American made files at a local flea market for $10.
There are several different sizes of flat files, a couple of round ones, and a few three cornered ones. I'd like to make a safe edge on one or two of the three cornered ones, for dovetails and such. Any tips or precautions I need to know about first? Thanks.

 

[kansas_volunteer]

I just bought a bunch(15-18) of good looking old American made files at a local flea market for $10.
There are several different sizes of flat files, a couple of round ones, and a few three cornered ones. I'd like to make a safe edge on one or two of the three cornered ones, for dovetails and such. Any tips or precautions I need to know about first? Thanks.

I did one on an India whetstone.

 

[akroguy]

It can be ground off but be careful not to overheat it which can change the temper.

 

[tom in nc]

It can be ground off but be careful not to overheat it which can change the temper.

Yeah, I figured I'd do it on my bench grinder, with my brand new fine stone. It would be nice, I suppose to have access to a milling machine so the cuts could be as straight and smooth as possible but I don't so I guess I'll do the best I can, being sure to go slowly and not overheat the file.

 

[Phil Coffins]

It’s really pretty straightforward, have a generous sized pan of water handy and dip more often than you think you should. Use the grooves as you grind to judge whether you are even all across.
IMG_0539 by Oliver Sudden, on Flickr

 

[Robin101]

I did mine on a belt sander and as Phil says, keep a pan of cool water close by, and use it! I've done hundreds of dove tails with it and still cuts clean.
Robin

 

[Clark Badgett]

Yeah, I figured I'd do it on my bench grinder, with my brand new fine stone. It would be nice, I suppose to have access to a milling machine so the cuts could be as straight and smooth as possible but I don't so I guess I'll do the best I can, being sure to go slowly and not overheat the file.

I do have access to a mill but won’t safe side a file on one. I use a belt sander with dunks in water after each pass.

 

[Sam squanch]

I just chewed the teeth off one side. Now I need to see the dentist.

 

[sdilts]

Ditto on the belt sander.

 

[tom in nc]

I have a table top belt sander. Guess I should install a fine belt for doing the file(s). Also, someone who's opinion I value says never oil a file, but chalk it, with common school chalk.

 

[Rob M.]

As stated before ... Just swipe it across the rotating grinding wheel then into water ....repeat until done , dont skip a water dunk or youll ruin the file . Those safe edge files I made are great , it helps so.much ... Best of luck

 

[SDSmlf]

It would be nice, I suppose to have access to a milling machine so the cuts could be as straight and smooth as possible but I don't so I guess I'll do the best I can

If you had access to a milling machine, what kind of carbide cutter would you be using to take the teeth off of a file? Believe good files check in with a HRC in the 70 range. Would be pretty tough on milling machine cutters….

 

[TDM]

Just like @Phil Coffins said.
Regular grinding wheel works fine for me as long as you keep it cool.

 

[bptactical]

The chalk keeps it from loading up with swarf(cuttings). Especially critical when filing soft materials such as brass, aluminum etc.

Another thing rarely discussed is proper technique- always lift the file off of the work at the end of a stroke. Too many people just drag the file backwards.
You dull the file and increase the chances of gouging your work.

 

[tom in nc]

I have removed my files a couple of times since putting them in the vinegar on Thursday evening, about 48 hours ago, and brushed them with a very stiff nylon brush. Most careful looking good.

 

[ZUG]

Grinding wheel, belt sander and a diamond or other type of stone will do the job. As others here have already said when using power tools you must keep the file cool. If it is too hot to hold on to then you need to get it into the water BEFORE you look at it to check your progress. Using a fine grinding wheel or a fine belt will heat up the file QUICKLY. It's best to start off with a course wheel or belt and then finish off with the fine stuff. Leaving a course finish is OK - the material you are filing will not know the difference

 

[tom in nc]

After pickling the files I cleaned them with degreaser and rinsed with very hot water. Then I heated them each with my MAPP torch just enough to make certain they were dry. Last step was dipping them in WD40. I don't buy WD-40 but I have about 3/4 gallon that my dad had 30 years ago. All but a couple look and cut like new again.

 

[CzarJL]

The best way I have found is a belt grinder or sander as you can keep the edge flat against the platen. On a bench grinder you are more likely to end up with a bit of an hollow grind or wavy profile on the file.
The most important thing is KEEP IT COOL. If the metal changes color you got to hot. Personally I keep the file very wet and as soon as its starting to look dry, back into the water.

 

[Felix the Cat]

A Belt sander or linisher will give a better finish than a grindstone.

Also, I use welder's soapstone chalk (looks like marble) to load up files.. much cleaner than board chalk.