2 questions-final edge-and ht with rust

Yo Mama

Yo Mama

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Sep 25, 2011
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1. before ht I've been cleaning up the rust built up from grinding and dipping in water, should I just not care, and clean up after ht because of the scale build up that will happen anyway?

2. I'm confident in my primary bevel, but after ht, how do you put on that final edge? I'm hoping to go with the table belt sander, 120 grit, but can't figure out how to make that final edge. Is it just easier to buy a mechanical sharpener?

Thanks!
 
If I'm not going to be grinding a blade immediately I wipe it off. I usually don't have any standing rust anywhere on the blade after grinding, so maybe look at your sequence to try to remove that issue from the process. I'm not really sure if it's a bad thing to just leave it. IMO, rust is never a good thing and I'm halfway OCD about things like that but have no evidence one way or the other.

If you use a sander or grinder to set the edge, be very careful about it. I've had to fix quite a few finishes by rushing on a sharpening with the belt sander, but I mostly use a belt finish of some type so it's easier to repair than a hand sanded finish or worse yet, polished. If your not right on you can leave little trail marks above the actual edge, and it can make a damn good knife look like crap. You will need a progression of belts probably starting with 120. I go up to an x5 trizact belt then the strop loaded with compound and seem to get a damn good edge but I'm sure other people have very different methods. Just make sure to dip EVERY pass and make them as quickly as you possibly can if you go that route,as you can easily overheat the edge. Very doable, but probably best to practice on blades you didn't put a ton of hard work into. I've been considering getting some dmt stones and water stones for sharpening, but it does take quite a bit longer than a powered method of some sort.

Justin
 
Not to hi jack the thread but, it is on topic. I'm still very confused at this. After grinding the initial edge down to your desired thickness, (.03-.04) whatever it may be for heat treating. After that do you continue grinding that edge down? Or do you clean up the grind and blade and sharpen from that .03 thickness?
 
colu41 said:
Not to hi jack the thread but, it is on topic. I'm still very confused at this. After grinding the initial edge down to your desired thickness, (.03-.04) whatever it may be for heat treating. After that do you continue grinding that edge down? Or do you clean up the grind and blade and sharpen from that .03 thickness?
Click to expand...

I have the same questions so no worries about hi jacking, throw information around at will!
 
Pre ht grind thickness is not the finish grind thickness for the way I do things. I get pretty close, typically somewhere in the .025 range pre ht with the 01 I've been using. I then grind to my final thickness after ht which will depend on the knife I'm making, but usually around .015 or less. I usually make thinner knives as I like slicers. I'm no expert and I haven't made a ton of knives, but it works for me, YMMV. You will always have some loss after ht from grinding the scale off and cleaning things up. How much is ultimately up to you, but I'd suggest doing a search on different edge geometries for different knife designs. I'm still in my testing phases on things like that, but feel like I've had decent success so far. From what I understand stainless blades can get a bit closer to finish thickness because it has a tendency to be more stable during ht, plus the use of stainless tool wrap to prevent scale, but don't quote me. Another thing worth searching because I just bought an oven recently and haven't worked with a lot of different steels.

Justin
 
Edge thickness for the average carbon steel knife blade ( and all liquid quench steels) - .020-.030" pre HT and .005-.010" post HT.
For stainless and air quench steels - .010-.015 pre and .005 -.010 post.
 
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