[jimmontg]

I did it all the time with paper cutting D2 blades 18" to 48" and they always warped, no exceptions. That said we tempered at 425, not 400. Most of my D2 knives had a little bit of warp. 1/32 isn't bad at all. Here's the catch, I used a hydraulic press which pushes down between two blocks and I also used my TIG torch which can lay down a very precise area of heat away from the edge and it curls up on the heated area side. I recently had a blade that was slightly warped and I straightened it with a vise and it worked. Depending how big the blade is depends on if the 1/32 is a lot. A 7" blade it isn't much, a 4" blade it is.

When it comes to applying heat to the blade Peters HT does it all the time. When I welded a bolt to a hidden tang I kept the blade area under an ice cold wet rag and stopped if I heard sizzling to add water. With a blade I heated the spine a tiny bit and immediately put a wet rag on it. Again I used the Cadillac of welding, the TIG, but a small oxy/acetylene tip will work too. Just a tiny bit and cool with rag. You'll be surprised at how much it curls back up with that small amount.

To bend it straight take little bites, bends, start at the very center of the warp and bend in opposite direction and move the blade a little at a time, turn it around and start in the other direction from the center. That should get rid of most the warp, remember I had a tolerance of +- 0.008 or .2 mm flat. Take a feeler gauge and see exactly how much warp there is. Don't expect to get perfectly flat with this method.

To anneal an air cool steel takes all day (and then some). You have to use your oven and drop it down so many degrees per hour, I don't have the chart right now and there is still a chance it warps again.