This carbide straightening hammer is made for correcting warps in hardened and tempered blades. It works by hitting the inside curve of the warp which will deform the material causing it to straighten out in the opposite direction. You do not need much force for this to work, I recommend letting the weight of the hammer do the work. All you’ll need is a flat metal surface to put your blade on, place the blade warp up and strike the inside of the warp 4-6 times and check your progress. You’ll be amazed how well this method works regardless of the steel type or hardness. I’ve used this method on thousands of blades with no issues on steels ranging from simple carbon steels to high alloy stainless at hardness ranges of 60-67RC make sure to temper your hardened blade before attempting to straighten. The divots left are very shallow and can either be left as part of the process or ground out, if you grind them out remember you must grind an equal amount off the opposite side to prevent counter warping from grinding. Some blades may need multiple rounds of straightening depending on the grind and specifics to that blade.