Turns that are too fast will over heat the blade tremendously and they will break on the spot every time.Blades should be tight.On the corners try to hollow it out a little before turning that will cut down the friction. i've thought of oil or wax ,maybe even coconut oil but never read anyone using the oils except for manual hand saw cutters.Keep track where you break your blades as that where you need to change what your doing,Slow speed mean less heat build up to.Sometimes i watch the blade go up and down whole cutting critical areas ,that's as slow as you go sometimes. If all you ever cut in coins is these your a master only breaking a few blades(6) perfect work.You will be the one to watch in metal cutting! :thumbs: :thumbs: :thumbs: :thumbs: