2XL, I did a small tutorial once and maybe someone can link it for us. I'm not good at that.
But basically you line up the blade where you want it in any mold. Close it and hold tight and pour. You will get flash, lead may even pour on the bench a little, but just clean up the head with a side cutter, knife, file, etc. A lot of it just breaks off.
You wouldn't want to make 100 like this but for 4-6 at a time or working on prototypes, it works fine.
The only time it doesn't work is when the blade has to be really close to the hinge and you cant get it to close properly.