Thanks Bob why do you use full comp chain , I think I read some where , where it cuts faster but finish is a bit ruff , is this correct
Perhaps I should be more specific, I use semi chisel, full comp because its cheap and if required can be turned into many different skip chain combos but you can't do the reverse.
I also don't want to have too may of rolls of different chain types and sizes on hand.
Full comp cutters can \ be converted to milling profile cutters either immediately or on successive sharpening if required - This something that can be done vice/versa.
Roughness of cut has nothing to with the fact that a chain is full comp or not.
The most important factor for roughness of cut is the operator, and to a lesses extent if its full or semi chisel chain.
There way are too many folks pulling new chains out of boxes without properly optimising all their chains and then making all sorts of claims about speeds of cuts.
Cutting speed testing is VERY time consuming and difficult to do accurately because the exact same piece of wood can never be cut twice so most comparisons are not worth much.
Cutting speed for all chains depends on chain optimisation - it may be possible to optimise a skip chain to cut as fast as a full comp chain on a particular saw, for a particular hardness and width wood, sometimes a skip chain may win the optimisation race other times the full comp chain will come out tops but usually there's not much in it.
One of the few things that can be said to be correct for full comp compared to skip chain is that full comp is slower to sharpen but stays sharp longer.
Can I get away with std chain for ripping or would that put too much load on the saw
30" bar on a 30" or larger mill will give 24" of cut.
In general I would say this is too long for milling on a 75cc saw.
However you could ease the load on the saw using a skip chain, or use a full comp chain and not drop the rakers so much.
Whether you use skip or stock chain, don't assume that chain out of the box is optimised for your specific setup and if you want to mill efficiently you still need to optimise the chain
The two critical angles are the top plate cutting angle and the raker angle (or depth)
The way to find the raker setting is to mill with it using stock chain
a) - if the chain grabs and stalls the saw then file the cutters back 2/3 swipes and try again until the chain stops grabbing.
b) - if it's cutting OK then start the optimisation by dropping the rakers 2-3 swipes and try, if it starts to stall - STOP- swipe the cutters 2-3 swipes and that's your raker setting.
To measure the raker setting you have to measure the raker angle - see the Milling 101 sticky for how to do that.
The other thing to note is that optimised cutting speeds usually occurs at settings that have greater vibe, and greater wear and tear on bars and chains. There's also greater potential for kickback although this is not that relevant on a saw in an alaskan mill.
I realise this is a lot of stuff for a newbie to take in before they have even cut one slab. To take a couple of steps back, YES you can use a non milling chain full comp out of the box to mill but limit the size of the logs you cut to less than ~18" in diameter until you get a feel for how the saw is cutting. I assume you have it all tuned up to run slightly rich etc.