How To Single cut file leaving waves in metal

Y

yugotprblms

Joined
Apr 5, 2010
Messages
25
I've been using the Pferd Chipbreaker to cut bevels in my knives, but it likes to leave a wavy pattern in the steel sometimes. It's not just aesthetic though, as you can feel the waves with your fingers. Is there any rhyme or reason to why this might be happening? I can't find anything on it.

Thanks!
 
Try finishing with draw filing.
Sit before your blade (clamped down) point towards yourself.
Have the handle of your file in your left hand and the tip of the file in your right. Now pull towards yourself.
It goes slow but gives good control
 
Hengelo_77 said:
Try finishing with draw filing.
Sit before your blade (clamped down) point towards yourself.
Have the handle of your file in your left hand and the tip of the file in your right. Now pull towards yourself.
It goes slow but gives good control
Click to expand...

Thanks, I have draw filed them out, but it's kind of a pain to have to file all that extra metal down, from the crests to the troughs of the wave. I guess I could strategically stop short of the lines I want to hit, and draw file the rest of the way.
 
Some pics may help :)
Draw filing does take time, just like hand sanding afterwards.
Also make sure no bits of steel get trapped between the teeth of the file. They leave deep scratches
 
I know exactly what you are talking about. But I could feel it happening as well, as it was caused by a weird harmonic or resonance between the file and blade, and the type of file didn’t matter. The only way I could negate it was rearranging how the blade was clamped. That was always a frustrating thing to deal with. More annoying than anything, as the filing was not as efficient when that was happening. It’s an odd thing to describe to those who haven’t experienced it. I don’t know exactly how you have your blade clamped down on the table, but try varying how you have it, and how it’s supported. Especially under the blade part of the knife.
 
It is called "chatter". There are several reasons for it. The big one is pushing too hard on the file. Next is file swarf ( bits of metal) getting trapped in the teeth as it goes across the surface. Using a controlled and smooth stroke, and file carding the teeth regularly will help a lot.

Also, files are \just like sandpaper. You need different cuts. Rough work is done with the coarse files - and they leave a rougher finish. Follow by a double cut and a finishing file if you want to reduce your hand sanding.
 
It’s definitely not a swarf issue, nor was I pushing down too hard on the file. Most of the time it would happen close to the plunge line area, and not so much near the tip. Like I said, I had to rearrange how I had the blade clamped in order to get the “chatter” to stop.

And who knows, what I experienced may not me identical to what the OP is talking about. But it would leave a wavy pattern when it happens, and again, rarely at the tip of the knife. If it happened, it happened closer to the tang where the blade was clamped. After more thought, I remember removing one of my 2 c clamps, that would help sometimes.
 
I find that if I get chatter all I have to do is change the angle of attack while filing.

Obviously you want to keep the file flat/parallel to the work, but try making your stroke more or less perpendicular to the work.
 
I usually hold the file at a 15 degree angle to the work and push with a perpendicular stroke. This is sort of like a very slight draw filing. It is sort of automatic with me, as I rarely just file with the file straight down at 90 degrees to the work. ( BTW, NEVER file on the upward stroke, as it will kill the file teeth). That may explain why Stuart had more problem at the ricasso, when he may have held the file more perpendicular. Perhaps moving the clamp allowed more angle to the file. Since I didn't see him filing, this is only supposition.
 
samuraistuart said:
It’s definitely not a swarf issue, nor was I pushing down too hard on the file. Most of the time it would happen close to the plunge line area, and not so much near the tip. Like I said, I had to rearrange how I had the blade clamped in order to get the “chatter” to stop.

And who knows, what I experienced may not me identical to what the OP is talking about. But it would leave a wavy pattern when it happens, and again, rarely at the tip of the knife. If it happened, it happened closer to the tang where the blade was clamped. After more thought, I remember removing one of my 2 c clamps, that would help sometimes.
Click to expand...


This is pretty spot on for when it was most prevalent for me. It happened on the second bevel of a blade, after I had already made the first bevel (meaning on the other side of the knife) with next to no issue. It was real strong close to the plunge line, and not nearly not-existent elsewhere. Filing in different directions seemed to help; up and away from the plunge line vs up and towards the plunge. I never could make it totally go away though, as it seemed to always want to come back.

I also managed to get it to happen the other day trying to take down and roughly square a part of the butt of the knife. It got all wavy there too. I'm sure there's some pattern I am missing, but I can't figure it out. A large part of me just wants to get some big, angry, double-cut bastard to try to avoid this.
 
Last edited:
Here is what the waves look like.

wI4JMPL.jpg


As you can see, they tend to show up right around the plunge line area. Not so much elsewhere.

And this is the overall set up, in case it helps to see how I am doing things.

SYLrZha.jpg


I know plenty of people don't care for the bevel jig, but I get much better results with it than freehand.

Thanks
 
Why are you fixing blade that much in left side ? Try like this ...and see if wave will disappear . You can finish that angle on plunge line last .....
PS . I like shape of that blade :thumbsup:
ATLioOX.jpg
 
I don t like that jig .... uncomfortable for work . Raise the front part where you fixing blade to make room for left hand . .. .

Yvagq23.png
 
Natlek said:
Why are you fixing blade that much in left side ? Try like this ...and see if wave will disappear . You can finish that angle on plunge line last .....
PS . I like shape of that blade
Click to expand...

I put it that far to the left because that's what fits the angle of the plunge line I created with a chainsaw file. How would I do it with doing the plunge line last? Would that create high/low spots?

And thanks.

Natlek said:
I don t like that jig .... uncomfortable for work . Raise the front part where you fixing blade to make room for left hand . .. .
Click to expand...

The jig doesn't bother me too much, but it's not my main concern right now.
 
yugotprblms said:
I put it that far to the left because that's what fits the angle of the plunge line I created with a chainsaw file. How would I do it with doing the plunge line last? Would that create high/low spots?

And thanks.
Click to expand...
Leave plunge line you created with a chainsaw file as it is and grind like this ...you will finish that small part last . I can bet that if you move blade as I say you will have no waves , look at the angle on file teeth .. .
vnFN9L5.jpg
 
It looks to me like the problem is with the section of particle board (MDF) jig the blade is clamped to. It is not stiff enough and causing the chatter in the jig/board rather than the file itself. The waves are worse at the plunge line side because that is at the end of a cantilever beam where you have the most deflection / chatter. You need to make a much stiffer jig to clamp the blade to.
 
I agree. The chatter area corresponds to your overhang. It gets worse as you go because you have more surface contact between the file and blade, increasing friction, swarf, and file "skipping", leading to chatter.

Maybe face glue a few yellow pine 2 x 4's into a 4" wide stack and then run them edge up through a jointer and planer. That should give you all the stiffness your jig needs.
 
You must log in or register to reply here.
Back
Top