I make a lot of sheaths. Once the are done I oil up the knife, wrap it in saran wrap and stick it in the wet sheath hard and work the leather with my hand till it fits well then either stick it over a heater vent or in the summer in the sun and let it dry well. Remove knife, wipe it down and lightly oil it, let sheath dry some more empty, then start oiling it. If you want to speed things up wet the leather well with alcohol while you form it. Gets just as pliable and drys much faster.