Ok thanks, I get that, being its a long tool with sideways force. But if that was a 20mm or 25mm dia tool using compressed air, it more than likely wouldn't of snapped eh ? The shell mill was impressive in that video. But if the space was tight and you were forced to use an endmill, maybe a reduced neck endmill would be the go ? Speaking of which, I cannot find reduced neck endmills on aliexpress.