# Double power head bar?



## Boon (Sep 5, 2013)

Any advice on running a double power head bar?

Am currently running a 660 on a 48 inch Alaskan but finding it a bit slow, we all know how hard it is to mill 6 - 8 hours and be fit to work the next day.

Hoping to cut through logs a bit quicker with not so much effort.

Which would be better two 660's or two 880's


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## discounthunter (Sep 5, 2013)

how long is your bar. if your cutting 48" i would say a 660 is too small.an 880 or 3120 husky may be a way to go.still will be slow but a little easier on the power head. knowing aussie woods are notorius hard, im not sure anything will be fast,lol.


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## BobL (Sep 5, 2013)

Boon said:


> .
> .
> Hoping to cut through logs a bit quicker with not so much effort.



The most tiring thing about CSMing should not be the cutting but the movement of the cut slabs.

Assuming you are not making full width cuts all that often and the saw is not bogging down too much I'm guessing you are just pushing the saw/mill too hard which should not be necessary.

Are you
- getting the logs up off the ground and/or sloping the logs?
- using log rails for every cut
- using progressive raker depth setting
- how often do you touch up the cutters?

RE: Dual head arrangement
Remember CSMs are chain speed limited so doubling the power doesn't increase the chain speed so cutting speed won't increase much unless the rakers are dropped substantially -


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## PhilB (Sep 5, 2013)

Two power heads won't increase the chain speed, but if a single power head is bogging down, two power heads potentially have double the torque. I use two 84 cc power heads and it works well although I haven't milled more than 35" oak. My signature has a link to my mill.

Phil


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## Boon (Sep 15, 2013)

am cutting at about 35 inches at max ATM on a 48 inch mill

Not always able to slope the logs due to weight or position

And have taken Bob's advice on using log rails on every cut

I usually only sharpen the cutters on a c/s grinder as it saves my sanity sharpening every tooth, but stop and change chains when the pressure to cut shows the cutters are blunt

Bob am not sure what you mean by - using progressive raker depth setting. I usually set the rakers to what Stihl recommends...there is a tool I purchased that lies across the teeth and shows the gauge needed for the rakers to be set. All are set to the same height, should they increase and decrease across the chain or all the same height at the same time

Yes understand the speed won't increase but am hoping there will be more torque when needed, like in fresh wet woods & hard woods. The 880 is a bit out of my price range ATM so was thinking two 660's will do the trick especially when am using the full 48 inches. Finding the 660 will bog down at times.

Recently read a web page where the person stated after tests the double headed bar/saw arrangement will only be of use in wider cuts, I can only guess as there are more teeth cutting and the double torque come into play as mentioned in your responses.

I have concerns when turning up to any customers place to mill out the full 48 inches and the torque is not there thus effecting the speed of the cut. Aussie hardwoods are just that and a wet log does not help from experience so far.

any suggestions on how far to drop the rakers in hardwood on the 660. 

Think soon will be attempting to cut an old gum that has been on the ground for about 5 years and is about 35 inches wide at max width. Am hoping this will indicate performance and if anything needs to change on the set up.

Thanks for the replies and help


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## BobL (Sep 15, 2013)

Boon said:


> I usually only sharpen the cutters on a c/s grinder as it saves my sanity sharpening every tooth, but stop and change chains when the pressure to cut shows the cutters are blunt


I don't wait for the cutters to go blunt but touch up the chain after about every tank full of mix - that way the cutters don't go blunt. On some cuts that means touching up after every slab, just two swipes per cutter is enough to stop the cutters going blunt.

Although I have many chains for my 42" bar I can touch up manually about as fast as it takes me to swap out and re-tension a chain. 
On my 60" bar I also do it manually on the mill because I only have 3 chains for that bar and would run out of chains if I constantly swapped chains.

Have you removed the bar clamps and drilled the bar because this makes chain removal much faster.



> Bob am not sure what you mean by - using progressive raker depth setting. I usually set the rakers to what Stihl recommends...there is a tool I purchased that lies across the teeth and shows the gauge needed for the rakers to be set. All are set to the same height, should they increase and decrease across the chain or all the same height at the same time


Progressive refers to dropping the rakers further as the cutter wears. Most conventional raker gauges use a fixed or constant depth eg 0.025" but this only works for near new cutters. The raker depth should be progressively dropped as the cutter wears. A basic guide is the raker depth should be about 1/10th of the cutter gullet width so when the gullet is 0.5" the raker depth should be about 0.05" - It sounds like a lot but it really does work. 

There are jigs around like the Carlton File-o-plate or the husky raker guide but these are generally conservative raker setters.

Instead of raker depth we normally talk about "raker angle" and ideally you want something that sets the "raker angle" to about 6º+.
I use 6º in hard aussie woods (wet Janka hardness above ~2000 lbs ) and 7.5º for softer woods.
Members like Mtngun use 9º which for new chains which is equivalent to a raker depth of around 0.04"

To read about how to set "Raker angles" see http://www.arboristsite.com/milling-saw-mills/93458-8.htm#post4107285
Unfortunately the diagram link (showing what is meant by raker angle) is broken but it is posted in the next post in that thread - 



> any suggestions on how far to drop the rakers in hardwood on the 660.


see comments above


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## Dai Sensei (Sep 20, 2013)

Based on Bob's recommendations, I adjust the rakers too, it does make a difference. I usually get a reminder that they need a trim when the scarf comes out like powder on a log that normally it is courser (super hard dry logs come out like powder sometimes anyway).


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## Boon (Sep 20, 2013)

an expensive question and realise the consequences of hitting objects, has any one tried carbide?


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## hypnolobster (Sep 24, 2013)

BobL said:


> Are you
> - getting the logs up off the ground and/or sloping the logs?
> *- using log rails for every cut*
> - using progressive raker depth setting
> ...



Can you talk a bit about that (or suggest where you've talked about it before)? I do everything else (I even use a hi-lift jack for getting logs up on sills to cut!), but I haven't seen any talk about using rails for cuts after the first slab. Is it a friction thing?

I'm using granberg EZ rails at work currently and they're pretty nice, but if rails make a big difference in friction, it'd be really easy to setup two rails of extruded aluminum with bars between and just tack them down flat with a few duplex nails.


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## BobL (Sep 24, 2013)

hypnolobster said:


> Can you talk a bit about that (or suggest where you've talked about it before)? I do everything else (I even use a hi-lift jack for getting logs up on sills to cut!), but I haven't seen any talk about using rails for cuts after the first slab. Is it a friction thing?



Friction is part of the answer. I have HDPE skids under my mill rails which slide a little better on cut wood surfaces, but they slide even better on hard metal surfaces like log rails. If the saw/chain is on song this picture show how little slope I need to get the saw cutting.






The main reason I use the log rails is because it gives me somewhere off the ground at the start to perch the mill while I start the saw, and at the end of the cut the mill has somewhere to perch while it cools down. That way I am not carrying a running saw at the start or end of the cut.

The log rails can also be used to correct for any twist that might have developed in previous cuts. This is done by checking the two ends of the cut using a digital angle finder. Thin long wedges under the rails are used to remove the twist. This requires the use of stuff log rails OR lots of supports under something like ally log rails.

The log rails make it easier for the mill to move smoothly so I think it helps in getting a good finish.

I don't use them all the time - mainly for wider cuts.


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## sun64 (Oct 10, 2013)

There are pros and cons with the set up. The thing with double headed chainsaw mills is that you need another power head, more fuel and usually a helper unless you set up both throttles with a single control.
I have heard of others that have run different sized power heads. They will even out when running.
You will get more power and torque, and if using larger saws, there should be no bog down. You will get higher rpm in the cut than a single head so that will give a higher chain speed than a lower rpm/ chain speed.
You wont need an aux oiler .
And you can get faster chain speed . You have the power so larger sized sprockets can be used increasing chain speed and still have reasonable torque because of the double headed set up.
There is a guy on e bay selling 9, 10 11 and 12 tooth sprockets for 090's and 880's .
You will need more chain links in your chain to suit these sprockets.
The one thing with larger sprockets is to not go too big a tooth count and make sure your bar is in good condition.
The larger sprockets will have the chain sitting in the bar groove higher up from the bar heel so with sloppy bar grooves etc there is more chance of chain derail. 
If say you had 2 x 880's , running 2 x 10 tooth sprockets that would make a fair difference in chain speed over the standard 7 tooth sprockets.
The bigger the power head, the bigger the sprocket can be used 
If you had seriously wide slabs then that would slow down the saw up but not as much as a single head.
So you will have the cost of the bar, another power head, repairs , fuel and probably a helper but hopefully less time milling and breathing in fumes and dust. Also depends on how much time you have / want to spend milling.
Cheers Wayne


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## tolman_paul (Oct 10, 2013)

The one real bummer with dual powerheads is one of the heads is upside down. Doesn't sound like a big issue unless you need to add fuel and/or oil to the powerheads while part way through a cut and realize you have to back the whole rig out of the cut and flip it over to add fuel and oil to the upside down head.


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## betterbuilt (Oct 10, 2013)

tolman_paul said:


> The one real bummer with dual powerheads is one of the heads is upside down. Doesn't sound like a big issue unless you need to add fuel and/or oil to the powerheads while part way through a cut and realize you have to back the whole rig out of the cut and flip it over to add fuel and oil to the upside down head.



That's what I thought, but it's not the case. The power heads would both be fuel and oil caps up. The way your describing they would be turning against each other and that wouldn't work.


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## tolman_paul (Oct 10, 2013)

betterbuilt said:


> That's what I thought, but it's not the case. The power heads would both be fuel and oil caps up. The way your describing they would be turning against each other and that wouldn't work.



Hey, you're right! I should have drawn a picture the first time to get it clear in my head. I've had too little sleep and too much coffee, the old grey cells are barely firing.


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## betterbuilt (Oct 11, 2013)

tolman_paul said:


> Hey, you're right! I should have drawn a picture the first time to get it clear in my head. I've had too little sleep and too much coffee, the old grey cells are barely firing.



I know exactly what your talking about. I thought the same thing till I came across a thread with some drawings in it. I was going to try running two power heads but decided to just get a bigger saw. It's all good.


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## Boon (Oct 13, 2013)

sun64 said:


> There are pros and cons with the set up. The thing with double headed chainsaw mills is that you need another power head, more fuel and usually a helper unless you set up both throttles with a single control.
> I have heard of others that have run different sized power heads. They will even out when running.
> You will get more power and torque, and if using larger saws, there should be no bog down. You will get higher rpm in the cut than a single head so that will give a higher chain speed than a lower rpm/ chain speed.
> You wont need an aux oiler .
> ...




Sounds like more trouble and money than it's worth until the time arrives, time for a bigger saw.


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## IanB22 (Oct 14, 2013)

*I think...*

And this is with very limited experience with 'just' a 394xp. If you can go from the 660, up to the 3120, and go up to an 8pin rim, and move down to 3/8 chain if your on .404 or down from 3/8 to .325 you would see SOME improvement in time. And, if you aren't sharpening your chain with the right raker height on the 3120, you won't get the advantage. 

Also, it appears 35" logs down in Aussie aren't as 'rare' as I originally thought, so if you DO start cutting large logs and want speed, you need more displacement, and you need more chain speed.

However, I think your post is about fatigue, and there are LOTs of ways to improve that, using a winch is probably the 'best' example that gets you up out of the fumes, and lets you apply constant pressure on the saw and removes you from a lot of the injury opportunity of standing 'behind' the saw. Also, if you are going 8 hrs a day, maximize the cutting time, by having the saw, and bar and guide setup a head of time. Even at 35" width, you should get between 10-20 minutes a slab, and so it's the time 'between' the cutting that adds up to a LONG day.


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## sun64 (Oct 14, 2013)

In regards to changing chain sizes, 3/8 chain has a smaller kerf so less bite in the cut than .404 chain.
This chain would help the 660 etc than .404 when slabbing.
The other thing though with 3/8 chain is the chain speed is slower than .404.
I have 3/8 and .404 sprockets and the difference is about a tooth extra for 3/8 to get to the same size as .404 7 tooth sprocket
Another thing with .404 over 3/8 is it will stay sharper longer with larger cutters..
I know of other guys today that will run .404 even on a 460 for just that reason when cross cutting.
It would be interesting to see if someone ever did a comparison in timed cuts between 3/8 and .404 chain.
If you ground your .404 down to 0 or 1 or 2 degree top plate angle , that would help with faster cuts.
Wayne


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## splitpost (Oct 14, 2013)

running the larger kerf chains can run into issues ,it some times is the difference whether you get 4 boards instead of 5 out of a cant, personally I run 3/8 semi and that serves me well,as for the guy selling big sprockets on ebay,thats fine if your willing to pay double for those sprockets but they can be had for a lot less direct from the good people at DANZCO, big sprockets and chain speeds of that sort will beat your chains around bad,i stick to 7 and 8 pin ,I have tried 9,10 and even 12 but rather leave them for crosscut play


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