I did something similar 2 months ago. I stabbed my radial artery. Blood was spraying out like crazy, and wouldn't stop, even with pressure applied. With every heartbeat, the wound would weirdly bubble with blood. The way I stabbed my wrist was straight down and parallel to my arm (the old down-the-street direction). Because I stopped after merely stabbing, I didn't separate my skin that wide. It was a slit. If I had sliced more directionally, I'm sure I wouldn't have been able to close my wound without medical help and a tourniquet. Of course, that would also be more painful. Because my wound was deep but not wide, I could bandage it tightly enough to close. I don't know if your wound is similar, but it sounded familiar to me. I think this method is certainly possible, especially now that I have some detailed experience. If I ever want to use this method (it's not my first choice), I plan on trying to widen the wound and stabbing the artery multiple times, just so that it's harder to close. Maybe even both wrists to speed things up. Once you're below the layer of skin, the blade causes a dull ache rather than sharp pain, so it's bearable. Now that you've cut deep enough before, you'll have scar tissue in the same place. This makes it really easy to try again since you won't feel as much pain. It's a time consuming method, so make sure you're alone long enough. I hope my detail helps.