That is actually an oversimplification. Different steels have different tolerances to heat.
Quote:
Originally Posted by Irishsquid
"grinding without a cooling agent (like a water saw but a grinding wheel, either a water trough or spray nozzle) Will -absolutely- and without a doubt destroy any hardenning or specific tempering; making the temper uneven and in some cases taking it out all together. "
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Rules of thumb:
1) If you're going to use a powered sharpening system, you do indeed want to keep your blade cool. A bucket of water is fine. But heat is a function of belt speed, belt grit, pressure, and cross section of your workpiece. As an end user, you don't have any control over cross section. With a low end machine, you don't usually have control over speed. You're going to be using a higher grit belt for sharpening. So that really leaves us with one variable that a typical person can control, and that is pressure. Go slow. Go smooth. Go light.
2) Just buy the HF 1x30 and be done with it. You don't need guides, and honestly, if you're going to use a powered sharpening system, you're better off learning to do it freehand. In my eight plus years as a full time maker, I have never ever relied on a guide for sharpening, and I have never wrecked a blade sharpening. Although now I've probably jinxed myself.
3) Do not wear gloves. First, gloves and running machinery are a bad combination - they tend to get caught in moving parts. This will ruin your whole day. Second, gloves will prevent you from feeling what is going on with the steel. What we're focused on here is temperature. When you're sharpening, you're going have one hand gripping the handle of the knife and the other pinching the blade. I usually try to pinch as close to the tip as possible, and as close to the edge as possible (without grinding off parts of my fingers of course). Why? Because this is typically where the blade is thinnest, and where it will most quickly be affected by heat. 130F is right around the max where most humans can comfortably handle a piece of steel. This temp is also far below where the temper in your steel is going to be impacted by heat. If if it's starting to get uncomfortable for you to touch, get it into your quench bucket. Simple. No more wrecked blades.