Buffing: Do you bother to keep your blades cool?

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godogs57

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Apr 16, 2004
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Got a question: Some of my blades require more buffing than others to get a properly finished product. I have quit using ATS 34 because of the inconsistancy of the product. (last 6 sticks, 2 were eaten up with inclusions/crap/etc). I am now going with 154CM and CPM154CM. When learning the craft, my mentor (strictly a 440C man) showed me how to buff blades prior to attaching handles...he would buff the ever living hell out of the blades with no regard to the obviously high temps on the blade he was causing. His choice in buffers was a 1.5 hp Baldor because anything less would bog down when he was "gettin' down on the blade", even bragging that he caught a hard wheel on fire one time it got so hot! Well, this was the guy I learned from and I knew no better. It suddenly dawned on me, after getting my own heat treating oven and learning about that end of knifemaking, that I might be ruining my ht/temper of the blade by copying his buffing technique.

I now keep a bucket of water next to my buffer and really watch what I am doing now...buff till it starts getting hot and immediately dunk it...same as when I am grinding...not letting it get too hot.

I am just wondering if I am on the right track with this situation. I posted a question awhile back about a blade that just plain old would not sharpen and a reply was received that I may have screwed up the heat treat in some way and in fact annealed my blade unintentionally. That got me wondering if I am thinking correctly about all this.

Your two cents worth is appreciated!
 
I grind my blades to 800 grit, then hand sand lengthwise with WD 40 and 1200grit paper. Only light buffing with K and G stainless or pink no scratch compound is required after sanding - no need to worry about heat. The hand sanding also minimizes the problem of grain showing in the steel after buffing.

Thanks to Jeff Higgins for this technique.
 
If your getting the blades hot enough to the point that you can burn your fingers, they are getting too hot! You probally won't change the temper but you could cause yourself bodily harm from not being to hold onto it.
 
I only use the buffer for handles. I finish my blades on a fine scotchbrite belt.
Scott
 
I wouldn't ever buff that much. If you need to buff that hard, you are just blending scratches, rather than buffing. All my buffing equires only a light touch. I would take it much higher in grit first.....
 
Your mentor is a crazed man. You dont even need a buffer. I seldom use mine but if I do it is for only about 30 seconds. Listen to these makers and follow their suggestions.
 
It's very easy to overheat a blade on the buffer. With 440C, the tempering is done at roughly 400 degrees and it only takes a couple of seconds to reach that along the edge or point if you're pressing hard. The edge is the part that all the rest of the knife supports. Without that, it's not a knife, IMO.;)

ATS34 or 154CM is more forgiving as it's tempering temperature is over twice that of 440C, usually, so It's safer as far as overheating, you have more leeway.
But again, you can reach dangerously high temps in the thin edge/point area quickly.

The bare hands will burn at about 125, 150 degrees for sure, so that's not a good judge, but it is a guidline that you're starting to heat up and if not cooled, it can get really hot rapidly. If you get it hot enough to ruin tempers, you'll most likely discolor the blade.

It is a good idea to keep it cool anyway, if only for your hands sake if nothing else.

I use a very light touch on the buffer and use it mostly for handles anyway, preferring satin finishes(either hand rubbed or machine applied) for blades/guards.
 
There're 2 Schools of Buffing: one with folks really leaning into the buffer.

Others say that if you have to apply this much force, you don't add enough of the buffing
compound. They prefer much lighter touch and add compound every 20-30
secs.

My buffing preferences are somewhere in the middle :) . I never get the blades close to tempering temps, when buffing. I mostly buff bare-hand,
so you feel when the temp rises and back off.


Have a few compounds, including coarser grit, handy - this is how you polish and color. Think of a dull belt - no matter how hard you feed metal
into it you're not getting much of cutting action going.

http://www.grizzly.com/catalog/2006/Main/170


Grizzly has some excellent hard buffing wheels:

http://www.grizzly.com/catalog/2006/Main/168 , yellow on the bottom left. Boy do these cut !

If yer buffer is 3600 RPM, stick to wheels 8" or under.
 
Thanks for your help....I have been careful not to get down on it, but got to thinking about it and wanted you folk's opinions. I appreciate your replies.

Hank
 
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