Mine is the original Alaskan sawmill made by Granberg. A friend has a knockoff made in China that cost about a third less than the Granberg and it is almost identical to the Granberg. These are the only two chainsaw mills that I am familiar with, and they work great.
The two best tips that I can give regarding chainsaw mills is to use a very powerful saw, and razor sharp ripping chain. The two largest professional Stihls are the model MS 661 and their largest model; the MS 881. Here are specs for the two models:
MS 661 - 7.2 bhp - 91.1cc engine - powerhead weight is 16.8 lbs
MS 881 - 8.6 bhp - 121.6 cc engine - powerhead weight is 21 lbs
My old Stihl 064 has very similar specs to the new MS 661. For any log over 30" I would not want to use a saw with less power than the 064 or the MS 661. I have been tempted to get a new MS 881 but that is a heavy and expensive beast and my 064 handles most of what I mill. When I start milling the 48" diameter Bigleaf maple, I will be wishing I had the MS 881.
I have tried almost every hand filing contraption on the market for filing saw chain. Those devices work but they are slow and tedious and you will never get as perfect of a sharpening as with a professionally sharpened (or new) chain. Finally I got a bench mounted Tecomec Jolly Evo chain grinder similar to what most chainsaw shops use. A bench mounted saw chain sharpener has several angle settings that no hand filing device will have (top plate angle and tilt angle). When you sharpen a chain with a device that does not include the top plate and tilt angles, the chain will not cut as smoothly and efficiently. See illustration below from the Tecomec chain grinder's manual.
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When you buy a new saw chain, the angles above will be listed/illustrated on the box, however the terms (top plate, vise angle and tilt angle) may be different. There was a learning curve to using the bench mounted chain grinder but now that I have mastered it (I only ruined one chain while learning) I would never go back to any type of hand filing device!
I use Granberg ripping chain (filed at 10 degree "vise angle" as per Granberg) and I have four chains on hand. When you are milling a log, if it starts cutting slowly; resist the temptation to keep cutting; stop and put a freshly sharpened chain on and then go back to cutting. At the end of the day I re-sharpen any chains that are dull on the bench grinder.
One more tip for now: I use a 10' section of an aluminum ladder for the first cut. After the first cut, which establishes a flat surface, you are done with the ladder. There are other ways to do this but the ladder works well for me. I drilled holes through the rungs of the ladder and I screw the ladder to the log with a screw gun. Just make sure that your screws are shorter than the depth of that first cut. I learned this the hard way!
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