I made a punch version. I had plenty of 1" brass rod laying around so I drilled one end and JB Welded some carbide rod in. I used 3/8" carbide rod and rounded it on the grinder after it was all glued up. I wanted to know how much pounding it would take to fracture the carbide (or the JB Weld), so I went cro-magnon with it on a banana shaped fillet blade and it ended up cracking my tempered blade... so don't go all cro-magnon with the smackety-smack. But the carbide will hold up if you're wondering.
Mine works within reason, but it's not going to take out a 1/4" warp unless I'm just doing it wrong. Anyhoo, there's an easy solution for AEBL and other such stainless...
Great piece of advice I got from Steve Miller (Bladegrinder) on here a long time ago: Stainless takes a lot longer to fully harden than you think. It is NOT like carbon steel where it comes out of the quench glass hard. When you pull AEBL out of the quench plates and you can hold it with gloves, if it's warped you can gently bend it for a very long time. You can literally straighten it with your gloved hands, and it's easy- so be gentle.
If the steel is that prone to warping that it comes out of the plates and warps, it's going to try to warp over and over again. Straighten it when it comes out of the plates. Then, and only then, clamp it to some bar stock or something before you do cryo / freezer. Keep it clamped all the way through the cryo and all the way through the temper cycle. It will stay straight then. It may pick up the tiniest bit of warp after it tempers but by then it's truly hard and the warp should be so minor that you can center scribe it and grind a straight blade out of it.
If you straighten it after the plates and then try to cryo without clamping it, my experience is that it will go banana shaped in cryo (and then fully harden) and the only way to straighten it then is with a torch and your vise. Maybe you'll get lucky and it will be minor enough to use the carbide hammer/punch.