Sawmill chainsaw Questions

[symamania]

Gday guys more CSM questions! I had these questions in another topic but was politely suggested i start another so here goes Ill keep it short and not ramble on,

Do i remove the dog spikes from the saw for milling?

Do I run my chainsaw at 40:1 or 25:1?

When buying ripping chain do I buy skip tooth or just normal?

And also should i be running my saw richer?

Saw is a Stihl 076 with a 36inch bar

Thanks Lads

[lamimartin]

Hi, There is no question you've got enough power for a sawmill, your saw is designed for such workload. I don't see any reason to change the standard carb settings.

On my Logosol M8, I use a MS660 with dog spikes removed, otherwise it might just interfere with operation.
I don't have the service manual for your saw. I've never heard a recommendation to use a richer mix than 40:1 (what I use) instead of the Stihl basic recommendation of 50:1. I already have to change the spark plug periodically, but at 25:1 I would expect spark plugs to get fouled in no time with no benefit.

I have no indication of the diameter and type of wood you are milling. Semi skipped and skipped tooth patterns are most useful in clearing chips when ripping softwood logs larger than 24 inch for instance. On a Logosol M8 sawmill, this is the maximum manageable diameter, so I don't use skip tooth chains.  I noticed low profile chains are faster, but it may not be compatible with your 36" bar.

I hope this helps.

[symamania]

thanks mate big help. the logs im sawing range in sizes about the biggest would be around 90cm so semi skip is for mainly soft wood?

I`m sawing mainly hardwood sheoak, Jarrah and some willow for an example 

[clww]

No bad questions. I removed the bucking spikes on my 084 or 090 when milling. I will mix at 40:1, and use a skip-tooth chain set at 10 degrees. I don't rip too many trees, but this works for me.

[mobile sawmill services]

why does this question keep coming up, do I run at 40:1, 25:1 or something stupid, NO, NO, NO,  the modern oils are designed to run at 50:1 mixes, and your saws are designed to use this ratio, why cant users realise that when you use more oil, your not richening the mixture, you are in fact making it leaner, causing the saw to run hotter. more oil = les gas= leaner mixture. use the mix the manufacturer recomends, buy the best quality gas, and use good quality oil

[lamimartin]

thanks mate big help. the logs im sawing range in sizes about the biggest would be around 90cm so semi skip is for mainly soft wood?  I`m sawing mainly hardwood sheoak, Jarrah and some willow for an example 

Softwood, tends is easier to cut, but clogs the chain faster than hardwood. For logs at 90cm, the skipped tooth pattern is leaving more room for the chainsaw chips between the teeth waiting to be expelled because each tooth produces more chips as it makes a much longer pass than on smaller logs. A regular tooth pattern would cut faster at the beginning of the log but would drastically slow down and probably overheat as you get deeper into a very big log.

As for the oil mix, I agree with our friend that you can't go wrong with a 50:1 mix which is Stihl OEM recommendation as opposed to old school 2 strokes that called for richer mix. Let's say, 50:1 mix is mandatory minimum. If you are not 100% certain, dropping a few extra drops in the 50:1 mix is not as bad as too little oil. In fact, overheating will destroy lubrication, so it defies the purpose to run richer mix. You can compensate with your carb adjustments, but it ends up costing more in. fuel, oil and spark plugs, not to mention more air pollution. Manufacturers of 2 stroke engines have struggled with pollution standards in order to remain acceptable for newer government regulations.  For instance I got a 8HP Evinrude outboard (1985) that was labeled and marketed as designed for 100:1 fuel mix, but soon after, the dealers received a notice to warn them to get back to 50:1 because 100:1 made engine fail under warranty.  Things like that made customers suspicious that getting too far into pollution restriction may be at the expense of realiability. In fact, I'm probably closer to 50:1 than 40:1 on a regular basis. I simply compensate extra oil for the error margin caused by fuel and oil containers graduations as weather swells or shriks them. I prefer to add a little too much than too little.

Stihl recommends a MINIMUM octane level of 89 on MS660 user manual. I ALWAYS use FRESH super unleaded gas, and avoid using regular gas with ethanol on any 2 strokes engines. Ethanol in gasoline is apparently the most common cause of carb failure on small engines, because ethanol absorbs moisture and ends up degrading fuel prematurely. If you store gasoline more than a few weeks before you use it, it is better to use fuel stabilizer. Current automotive fuel shelf life is about 3-4 months.

[Kbeitz]

I think that some people here are forgetting that oil is also a fuel.
Chainsaws will run on diesel. This is my $0.02 but I don't believe you are hurting you engine one bit running with more oil. Diesel is an oil fuel not much different than your 2 cycle oil. I have never and I mean never hurt any of my engines run extra oil and I do so all the time. Adding oil to the gasoline will raise the octane  it's not a theory, it's a fact. Motorcycle racers add oil to there gas for an octane booster to win races.

[symamania]

I went into the stihl dealer today to have a chat with the lads, And the subject of fuel mix came up and they said i would be doing the saw a HUGE favour running at 25:1 fuel mix.. the saga continues

[Hilltop366]

Keeping in mind that "chainsaw milling" and "blocking and limbing" are two different things I would error on the side of caution and bump up the oil in the mix to 40:1 (if using oil that states 50:1) and as always adjust the carb to meet the current conditions and activity.

Also I would add that letting the saw run a bit under no load to let it cool down a bit would not be a bad idea after a long rip cut, if the saw is shut off right away it no longer has the fan on the flywheel to help cool it.

It would be interesting to have a temperature gauge on the cylinder head to see exactly what is going on.

[sigidi]

I don't entirely agree regarding skip chain only being for softwood ripping. On my Lucas Slabber you either use 3 skip or 5 skip chain. We only cut hardwoods and in qld our hardwoods are very dense. The Lucas manual recommends 3 skip chain for logs under 750mm and 5 skip for logs over 750mm.

Daily I run a skip chain on my 372xp with a 24" bar. It does felling, docking and ripping split posts. I don't use it for ripping slabs as I have the Lucas, but it does a great job with every third tooth removed.

[celliott]

I only run 32:1 in my 395xp for milling. 32:1 in all of my saws actually. Cranks are expensive.

Yes, I remove the spikes to get extra cut width. I use granberg ripping chain on big hardwoods, but smaller softwoods, I've used regular full chisel chain and it worked well.

[sandsawmill14]

for the record running a saw richer or leaner has to do with fuel to air ratio  not gas to oil ratio  ;)  i also run 32:1 

[celliott]

for the record running a saw richer or leaner has to do with fuel to air ratio  not gas to oil ratio  ;)  i also run 32:1 

Yup. You can run 20:1 and have the H jet tuned way too lean, screaming and burn it up in no time. Or run 50:1 and have it running pig rich and foul plugs. Proper tune and fuel ratio go hand in hand, but the tune is more important IMO.

Here's a video of me milling some sugar maple with 395xp. Listen to the tune. It is on the rich side, if I was bucking firewood, I would lean the H jet out some. You can hear it 4 stroke and clean up when I apply a decent amount of pressure to the mill and ease off.
Excuse my seesawing technique. Still a bit new to CSM'ing.

http://www.youtube.com/watch?v=GF93L6CFXLc

[Ianab]

I went into the stihl dealer today to have a chat with the lads, And the subject of fuel mix came up and they said i would be doing the saw a HUGE favour running at 25:1 fuel mix.. the saga continues

It may have to do with different fuel formulation in Aus and NZ? I've been told the same thing by both Stihl, Dolmar and the lawnmower dealers. To specifically ignore the manuals 50:1 mix ratio as it's not reliable with the local fuel.

As for the skip chain? It makes sense to me that you only have so much power and feed pressure available to cut with. It takes "'x" hp to drag each cutter through the  wood, and a certain amount of push to keep it biting in properly. If you are only pushing the cutter 1/2 as hard, it can't bite properly. If you increase the push, you have too many cutters digging in for the engine power, and the saw bogs down. 

With a skip chain in a longer cut, you can keep a sensible feed pressure, each cutter has the correct force on it, and the engine has enough power to drive them properly. So in a wide cut the skip (or multi-skip) works better than a full comp chain that's bogging down, or just scraping dust.  Full comp should work faster in a narrow cut.

[free_rider_151]

I run a moderately modified pioneer p61 with a 24" bar and .404 woodland milling chain. 32:1 @ slightly rich. Chain speed needs to be consistent. If you cant maintain speed when in the cut, put on semi skip. If that doesnt work, use full skip. If that still doesnt work, on a really long bar you may need double skip. Just my experience.... but my old saw is hard to compair to the fancy higher power stihl saws....

[Kbeitz]

for the record running a saw richer or leaner has to do with fuel to air ratio  not gas to oil ratio  ;)  i also run 32:1 

In cycle racing changing the gas jets has to do with fuel to air ratio.
The air intake does not change... So smaller jets causes a lean mixture

[black]

Your mix depends on your brand of 2 stroke you are using. Read what stands on the bottle, follow the mixing instructions on it and nothing will go wrong.
Listen to someone telling you how they mix and things can go wrong.
People always no better than the manufacturer.