Double ended chainsaw milling - What is it? Chainsaw milling usually involves using x1 powerhead. Double ended milling means you are running a chainsaw at each end.   Favourite question? Surely the chainsaws have to run at the same rpm or else one will be running the other. A resounding ‘no’ is the answer!   Say you have an MS880 and when you rev the ‘nuts’ off it unloaded it is running at 12,000rpm. Say you have another MS880 and you rev the nuts off that and it’s rev count is 1