Chain tension when milling

[gobbypunk]

Hi guys, a while ago I posted about a prob with chain tension on my 880 when I'm using my Alaskan Mill, its all over the place, what do you all think? I will start the saw, rev it a little and then need to adjust the chain half way through an 8 ft long butt. The chain will be too slack so I adjust up to finish the cut but the chain then gos tight. Sometimes its so bad that its cut one of the bolts that hold the uprights of the mill almost in half. By hitting that bolt my chain is never as sharp as it should be either. Could it be a problem inside the saw with the tensiioner? I have looked and can't see owt wrong - here is a pic of the bolt. Does anybody have any ideas about what might be going wrong?

[CJM]

Is your saw oiling properly?

[gobbypunk]

Hi its useing the same amount of oil its always used so I would think it is

Thanks Mark

[OliB]

Totally agree with CJM, does sound like an oiling problem. If your chain is then getting blunted on the bolts, it will overheat even more, and it sounds to me like the overheating is what's causing your issue.

 

From my own experience even just a couple of hours milling forces me to pay far more attention to the bar and chain than days worth of cross cutting. I might be called over the top, but I clean the bar grooves and bar oil holes, give the chain a quick tickle with the precision grinder, and check the nose sprocket for lubrication or build up of debris every time I refuel with my 880 in smaller logs, and have to do it every cut in things like 36" oak at 16 foot, or the chain and bar just over heat, the chain dulls, and it takes 4 times as long. I now also oil the nose sprocket a couple of times a day, more in the big stuff, which makes a big difference (didn't used to do this at all, taking the argument that once you start oiling the nose sprocket you could be preventing bar oil from lubricating the nose, probably more because that's easier than oiling it, than because I thought that was best practice if I'm honest). I wasn't that fussy a couple of years ago, the price I paid was wearing out a couple of nose sprockets, and killing a good bar.

 

The only other suggestion is tension of the Alaskan mill bar clamps. Are you using a torque wrench? I still don't do this by feel, since too much tension causes the bar clamps to squeeze the bar, and make it harder for the chain to travel in the bar grooves. Even with the torque wrench, once set up I pull the chain thru the bar to check I'm happy with the freedom it has. With my torque wrench I set it to the minimum recommended nm, as I have these issues at 17nm,but not at 14nm. Part of the same issue is getting the bar clamp, at the nose sprocket end, fitted no closer to the nose than the rivets that attach the nose sprocket to the bar (not the rivets of the sprocket itself), as any closer and that also limits the chains movement.

 

I don't know if other Alaskan millers have the same experiences?

[Mike Dempsey]

If you are using a 3' bar or more an auxilliary oiler would help to lubircate the bar and chain

[gobbypunk]

I dont use a torque wernch but have one I will give it a try and I have hard nose bar when I first had the mill it ran ok no probs so its doing my head in ive done nothing diffrent , i have striped my mill a d saw right down and given it all a good clean will have another go on friday and report the results I would appreciate someone else who has had an alaskan and an 880 to have a look with me if anybody out there is up for it

Thanks Mark

[CJM]

Get an old cleaning bottle and squirt the chain with oil when you're milling and see if it happenes again if the chain acts normal you obviously have oiling issues with your saw. If it keeps happening it could be anything like a poor quality chain, badly worn bar or sprocket you could even have a knackered chain tensioner or side plate and the vibrations are loosing the bar slightly

[Macpherson]

hi, until I got the mill I had no experience of running a 36" bar and was quite surprised how much the chain expanded when hot and just how slack it can get.

 

I would guess you probably downloaded and read the book by Will Malloff "Chainsaw lumbering" that was recently discussed on here, anyway if not, he`s got a lot to say on the subject of bars chains and also mounting the saw differently in the Alaskan to make maintenance and adjustments easier, although I`ve not tried any of his tips yet it makes interesting reading. cheers

[josharb87]

Are you using a solid nosed bar?

[Forest2Furniture]

I mill with an 880 both 36" & 47" bars and have never needed to use an auxilary oiler, make sure the oil pump screw is turned up high.

 

The other thing is the speed at which you push the mill along, to fast will cause the chain to bind and heat up, smooth and steady is what's needed, that's where a winch is handy.

 

The other thing is, if you're hitting the bolts that will be down to uneven tightening of the clamp, screw the bolts down by hand before using a spanner.

Edited March 19, 2015 by Forest2Furniture