Quick question- how hot is too hot while grinding?

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Omega Leather Works

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Jun 13, 2007
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Sorry guys, I did search...

I'm using a magnet while grinding. I've heard of burning the carbon out of steel. Is this a forging issue, or does it apply to stock removal too?

I understand the benefit of using sharp, low grit belts. I'm just a little worried about damaging the steel while I don't have "hands-on".

Thanks
 
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I'm not an experienced maker, but from what I heard, as long as you are grinding pre-heat treat, the normalizing and HT with take care of anything you could of done while grinding.
 
Learn to grind with your bare hands. If the blade is getting too hot to hold dunk it in the water bucket. Your blade will be fine.
 
i4Marc said:
Learn to grind with your bare hands. If the blade is getting too hot to hold dunk it in the water bucket. Your blade will be fine.
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I kinda figured that was coming. :D

I like the magnet. In another thread someone recommended I pick up a welding magnet from HF. I did just that a little while ago, but the thing is *really* strong. I plan to give it a go in place of my other one. Just don't want to invest what little time I have then find I ruined it before even getting it in the forge. But don't worry, I'll still be working on freehand grinding.
 
Strigamort said:
Sorry guys, I did search...

I'm using a magnet while grinding. I've heard of burning the carbon out of steel. Is this a forging issue, or does it apply to stock removal too?

I understand the benefit of using sharp, low grit belts. I'm just a little worried about damaging the steel while I don't have "hands-on".

Thanks
Click to expand...

You won't decarburize blade while grinding, unless it starts to glow :D
You will harden/soften the blade via grind tempering, but it is not a problem if it is done before HT.

After HT, you must keep the blade cold, colder than you think.
For some steels and blade thicknesses, grinding to "too hot to touch" is way to high, because the other side of blade is much much hotter.
 
Thanks idaho. Just made a quick dashi and heat treated it. The magnet was actually quite nice. I don't have any jigs and the bulk of the magnet helped hold onto the tiny knife. :)
 
I get the steel red hot when grinding profiles and bevels ( yes, it glows red). It won't hurt a thing. After grinding and before hardening, normalize the blade.

After HT, the steel needs to stay below 200F or it will affect the temper.

The best method of keeping the blade heat under control in post-HT grinding is to grind with bare hands. You will dunk the blade quickly as soon as it gets much above 100F.
 
I don't use the magnets after ht. In fact, I'm probably too careful after ht (if that's possible), dunking after every pass regardless of how it feels. It would help me to figure out where that line is, but I figure it's an experience thing. I realize that when you see color, you've botched it, but that's not much help when you really really don't want to botch it. :)

I've certainly gotten the steel glowing (just a little) while grinding, but since I've started using low grit (and sharp) zirc belts, I've noticed that it seems to be much less an issue.
 
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