2,493. Knife on One Side, Sickle on the Other

Hilchos Shechita 1:21

If someone took the jawbone of an animal with sharp teeth and performed slaughter with it, the slaughter is invalid because it’s like a sickle. However, if a jaw has just one tooth, then one may slaughter with it even at the outset despite the fact that it’s attached to a jawbone.

Hilchos Shechita 1:22

If one heated a knife in fire until it was white-hot and then slaughtered with it, the slaughter is valid. If one side of a knife is a sickle but the other side is good, one should not slaughter with the good side at the outset; this is a preventive measure against the possibility of slaughtering with the other side. If one did slaughter with such a knife, the slaughter is valid since he used the good side.