How do I tenderize tough ol blade steaks (boneless)

Beat it with a tenderizing hammer, or empty bottle of Rothschild Chateau 1998.

I don't know how you want to cook your steaks, but this is a cut that responds very well to braising. I've never grilled chuck steak, but will try June's suggestion above!

I would marinate it for a few hours. We do that also with chuck steak, often overnight, and it grills up fabulously. I will have to post the infamous Marinade later, bc I don't have it here on my work computer. Hopefully someone else will beat me to it...