Filing a knife a few questions

[johnnyKnives]

I read to get two files, a bastard mill file and a smooth tooth file. One of them, I guess the mill file, is supposed to be half rounded. Why do I want a half rounded one?

When I file the knife what approximate angle do I try and file at? Does it change in the filing process?

Do I have to hit it with the angle grinder first or just start filing?

Thank you.

 

[canid]

the only need i can think of for the half round is for doing convex curvature.

with that in mind, i've had to make due without one for that purpose, and have resorted to making contoured sanding blocks for abrasive paper. not nearly as durable.

there may of course be some applications for the half round that i am missing.

 

[lonepine]

Quote: Why do I want a half rounded one?

I can't think of a use for the rounded file as far as making the BLADE. However if you're making full tang knives then it will let you make fancier convex curves as Canid said. (It's not REALLY half round)


Quote: When I file the knife what approximate angle do I try and file at? Does it change in the filing process?

The angle depends upon how the blade will be used. I've seen figures of 18-22 degrees (9-11 each side). I would say you keep a single angle for a flat grind.


Quote: Do I have to hit it with the angle grinder first or just start filing?

Why would you want to hit it with an angle grinder? When filing the bevels on a blade by hand you make the most and easiest progress the 1st 50% of the way. You get a real good feeling as you see the bevel working its way up the blade at such a quick pace. BUT...as the grind line moves up the blade you have to remove more and more steel to make progress and it seems to take forever for both sides to reach the center line you scribed. Here is where I was sorely tempted to change the angle just to get it done. Learning patience and perseverance has been a couple of the most difficult lessons that I am still working on.

Seriously though I don't see how using an angle grinder to do some initial rough grinding would hurt anything. As soon as I figured out I could use my belt sander as I grinder I only used the files at the very end to clean things up. Use whatever you have on hand that can save you labor. You're going to make mistakes regardless of what you do, but each blade you make will teach you new things and the next one will be better.

You're probably also going to need a wood rasp for shaping the handle.

LonePine
AKA Paul Meske, Wisconsin

 

[canid]

to be honest, i've always wondered whey they call files which seem to be around 1/6 round half round to begin with. also i don't know why i typed convex earlier when i meant concave. damned fingers have a mind of their own.

 

[Stacy E. Apelt - Bladesmith]

Lonepine;
I believe he is asking what angle to hold the file at for each stroke, not the secondary bevel angle for sharpening.

Hold the file at about a 30-45 degree angle to the blades length. Take long smooth strokes....never back and forth. Putting a file handle on the file helps a lot. You can also draw file the blade. That is done by holding the file as described, but instead of stroking it , you just "draw" it down the blade length like it was a metal shave.

A half round file is good if you are only getting one file in each type. If getting several, then get most in double flat and one in half round. The curved profile is to shape the handle curves in both the wood and the tang metal. The half round side is not normally used on filing the blade flats.