saw sizes to cuting width information

[Rail-O-Matic]

For the past fifteen years I have been collating information on chainsaw milling systems and their effective uses, the following information is what I have worked out, some of it might be of use to those contemplating buying or starting out in the art of chainsaw milling.

A good guide to having all the power needed to mill any given timber with a portable chainsaw mill, is to take into consideration the following.

How much water has the timber lost after being first felled or being blown down and what type of timber and how often you might use your equipment to carry out this task.

Was the tree dead standing or growing, and at what time of year it was cut down, all these can have a dramatic effect to how much strain is put upon any given outfit or sawmill.

As an old teacher during my engineering apprentiship said to us all, there is no substitute for CC's, in part this is true, but not in all, this can be explained when comparing a bandmill to a chainsaw mill, a smaller or half sized engine on a band mill will give enough or the the same amount of energy needed to cutting the same log with a chainsaw mill, but lets concentrate on the chainsaw mill for now.

A chainsaw with a motor size less that 80 cc does not really give you the cost effective power needed to power a chainsaw mill greater than 20 inches, if you add an extra 30 % of power needed to cut along the grain to what the original manufacturer recommends for using a saw normally, you will have a better balance to power your chainsaw mill.

A chainsaw with around 7.5 Hp is really only cost effective when cutting widths of around 24 inches, it will cut wider material, but tests have shown that it is really past its limit after then and the long term effects upon the saw will soon show their face, not to mention the larger fuel cost of running for longer periods, will quickly out way the extra cost of buying a bigger saw motor.

For the best results, the biggest saws are what is needed to carry out the really big tasks of 36 inches and over and to gain back some of the handicap from really wide boards, a smaller curf or chain width is needed, which can easily be acheived today, with the miriad of different products on the market.

Other saw mills which I have experimented with are, larger 4 stroke engines with a vertical shaft outlay, converted to drive bigger bars of 50 inches and above, they consist of a conversion plate from motor to bar, rather like those seen on racing saws, they are driven by a conventional harvestor sprocket straight onto the engine shaft and thus onto the bar, which is mounted to the same plate, for the oil supply, I have fitted an external oil tank, driven by the crankcase pressure from the engine in question.

They have proved to be very cost effective, with an outlay for a motor of 13 Hp costing a third that of a big chainsaw motor, there is no clutch to soak up any of the power, so you get full power to the chain, with a top crank speed of around 3600 they are slower than a chainsaw motor, but the extra perifral speed of the larger harvester sprocket makes up for this.

The only down side of things is they definately need two people to guide them manually, but run nicely on any rail or trailer system and they are good for twice the capacity of a conventional chainsaw milling system.

for those who are interested I can send information on how to build youself something along the lines regarding the latter.

Its now 00.37 GMT, Happy new year to you all.

 

[woodshop]

Thank you for that rail-o-matic... very interesting, and informative. I appreciate you sharing that with all of us. You have really delved into the science of chain saw milling.

I for one am interested in your 4 stroke vertical shaft mated to a large bar csm. It would seem to me to be the most bang for the buck when slicing up very large slabs like something for a rustic tabletop. I don't suppose you have a picture of one you can post for us do you?

 

[lumberjackchef]

I would also like to see some pics if you have any. Four stroke engines are a dime a dozen around here. Thanks and Happy New Year!

 

[Ianab]

Lucas and Peterson sawmills both make 4 stroke chainsaw mills here in NZ and Aussie, and also an attachment for a chainsaw bar onto a normal swingblade sawmill.

The dedicated slabbers I have seen use in idler shaft to mount the chain sprocket. 2 reasons for that, the gearing can be adjusted by using different sized pulleys on the engine and idler shaft, so you can bring the chain speed up to normal speeds. And the engine crank bearings are protected from the side force and vibration that the chain causes. A vbelt drive system is pretty efficient and reduces the stress on the engine.

Lucas sawmills have shown a 9ft chainsaw slabber at last years Ag Fieldays, now that was impressive

Yup... I do have some pics

The chainsaw mills do come into their own with those big logs as those big slabs of wood a worth good money. The log they are cutting was 4,000 year old swamp kauri, (that is, the tree fell into the swamp 4,000 years ago and was dug out recently) and were selling for over $1,000 EACH slab.

Cheers

Ian

 

[Rail-O-Matic]

Thank you for that rail-o-matic... very interesting, and informative. I appreciate you sharing that with all of us. You have really delved into the science of chain saw milling.

I for one am interested in your 4 stroke vertical shaft mated to a large bar csm. It would seem to me to be the most bang for the buck when slicing up very large slabs like something for a rustic tabletop. I don't suppose you have a picture of one you can post for us do you?

Unfortunately I do not have any good pictures of the experiments I did back then, but I will have some when I have perfected things on what I'm doing now.

I started out using my old bogg standard shop bandsaw, a Startrite, which has the top section mounted to a foot or stand, it took these appart and made a simple metal plate to mate the saw and the standard horizontal 5 hp Honda GC160 engine together.

I soon realised the potential that the Honda engine gave me, with more than enough power to drive the saws 12 inch depth of cut, it was almost unstoppable, things were of course too heavy to operate by hand, but it worked very well, when mounted onto a simple space chassis or frame.

To mount the engine to the chainsaw bar, I took a plate of aluminum 3/8" thick, drill four holes in it where the standard engine foot has four holes, some are already ready threaded, where a standard generator or other fixing fasten to, all Honda motors have these, drill another hole so that the engine shaft can go through and big enough so that a spacer of 1-1/2" can be put through that hole.

Work out where the center line of the bar and engine shaft will be when everything is bolted in place and mark it.

For the bar bolts, use standard car stub or wheel hub bolts, they are ready made and have a splined area where they are pressed through and have a fairly fine thread for a good hold on things.

Along the center line work out where you will need to drill these bolt holes leaving enough room for the standard harvester sproket and the end of the chainsaw bar, you can experiment with different sized sprokets to get different chain speeds, press in the bar bolts, you might need to fit spacers inside the bar slot on some bars, this depends upon what size bolts you use, I used bolts from a light truck which fitted perfectly inside the bar slot.

To line up the harvester sprocket and bar I used diferent sized spacers, one below and one above the sprocket to do this.

For the bar clamp, I used another piece of the aluminum plate, and then cut a small slot 1/2" either side of the hole to allow for chain adjustment, then shaped it to fit and cover the oil holes on the bar to be used, I actually coppied the internal shape of a standard Stihl chainsaw side cover for this shape.

For the oil hole, drilled a hole opposite the oil groove in the bar, thread and fit a standard oil banjo union to that hole for the oil pipe to fit onto.

For the oiler system, take the opposite engine oil filler of any Honda, not the one with the dip stick fitted but the other side, normally another colour, drill a hole in the center, again drill and thread it to take another oil union for another pipe to fit, I used an in line non return valve for obtaining a positive pressure to pressurise the oil tank to drive out the oil, its as simple as that, there you have your hondasawmill.

Engine I'm using now is a Honda GXV390 13hp with a one inch shaft, Cannon 60 inch Superbar, giving almost 4 and a half feet cutting capacity.

There are swing mills like Lucas who first started out with chainsaw bars and Peterson who now have a nine footer, but we are talking big bucks for these, the mill I'm making is costing me under $ 1600 USD to make, that's saw frame and all.

There is no time consuming set up times and its totally portable and can quickly stowed away and moved around with any ATV bike, right into places where the former would only dream of going, my aim is to make the most portable system for the least money, or bang for your buck as you guys say.

Hope this is of help, for more detailed stuff, PM me.

 

[woodshop]

There is no time consuming set up times and its totally portable and can quickly stowed away and moved around with any ATV bike, right into places where the former would only dream of going, my aim is to make the most portable system for the least money, or bang for your buck as you guys say.

Thanks again for all that detail Rail... you seem to have a passion for this. As you know, not having room for a permanent stand alone mill, portability is paramount for me. Once in a while I do come across a really huge log that I have to slab down to size just to get my 36 inch (thus 32 max cut) csm on the thing. I was given a 4 ft wide 3 inch thick slab of apple once I plan on making into a kitchen table. Would be really nifty if I had the means to slice those myself without having to invest in a full blown csm that huge. As Lumberjackchef says, 4 stroke engines can be had pretty cheap if you dig around. So the main expense would then be the huge bar, not counting my time. What do you think of what ianab said concerning using an idler shaft to ease the power transfer to that sprocket?

thanks again Rail

 

[woodshop]

The chainsaw mills do come into their own with those big logs as those big slabs of wood a worth good money. The log they are cutting was 4,000 year old swamp kauri, (that is, the tree fell into the swamp 4,000 years ago and was dug out recently) and were selling for over $1,000 EACH slab.

Impressive ianab... VERY interesting pics. You were there and saw this thing in action? Curious how fast it sliced through that log. I assume it was pretty slow, given the size, but could you actually see the thing move?

 

[Ianab]

Impressive ianab... VERY interesting pics. You were there and saw this thing in action? Curious how fast it sliced through that log. I assume it was pretty slow, given the size, but could you actually see the thing move?

It took them a few minutes to get through that big log, I didn't time them or anything though. The guys are really just leaning against it keeping a steady presure on the carriage. You can see the sawdust being thrown in the first shot, so it's cutting fairly well.

Another thing I noticed was the chain configuration, extra super skip chain. You can see in the 3rd picture how it has a set of cutters about every foot or so on the chain. Peterson use a similar chain on their slabbing mill as well. The idea is that you can keep the pressure on each cutter and have it cutting to it's max. While if you have a full complement chain each cutter is just scraping off dust in the cut and the overall cutting is less effecient.

Cheers

Ian

 

[Rail-O-Matic]

What do you think of what ianab said concerning using an idler shaft to ease the power transfer to that sprocket?

thanks again Rail

I think it could be done, as on a chainsaw clutch, it has a direct drive to the chain and reduced in size to the drive sproket.

Using a harvester sprocket keeps the chain almost level with the bar end taper and is kinder to the chain because it runs with less of a climb onto the groove.
A big Cannon bar here in the UK cost an arm and two legs, but they are worth every penny, they are superbly manufactured and hardly bend along the length when held on their side.

The smooth power delivery from a Honda engine is also kinder to the chain with a less violent start up from standing and once in the timber they stay more stable and are much easier to control during a cutting load, the Honda does not die as suddenly like a chainsaw motor does.

If you hit these links, you will find some really cheap Honda engines for sale, they are made in China, they are exactly the same thing as a Honda made in Japan, but at a snip of the normal price.

http://xingyue.en.alibaba.com/product/50185911/10179207/Engine/Gasoline_Engine__EPA_.html

http://xingyue.en.alibaba.com/

With the money you will save here you can buy that top chainsaw bar and still have change to build the frame for it, now thats gotta be worth looking into.

 

[woodshop]

With the money you will save here you can buy that top chainsaw bar and still have change to build the frame for it, now thats gotta be worth looking into.

...so many tools, so many projects, not complaining, hope it never ends.

 

[Rail-O-Matic]

...so many tools, so many projects, not complaining, hope it never ends.

I have heard of those 13hp honda engines going for as little as $150.00 a piece in the USA, they are made in China, but I have been told that Honda themselves had a hand in setting up the factory in which they are made, but don't quote me on that one.

There is a tool hire shop here in my home town, who fits these motors to some of their hire gear, like whacker plates and generators, they say they have had no trouble whatsoever with them, as long as they are serviced regulary, at the prices they go for does it matter if they only last a couple of years, by that time it will have paid for itself many times over.

Genuine Honda GXV 13hp engine, 50" Cannon Superbar and chain, aluminum conversion plate, all the metal for the 15 foot saw frame cost me less than £700.00, that works out at about half the price of a new standard Stihl MS880 fitted with a Stihl 25 inch bar in the UK, this has got to be the cheaperst way forward for the low end user.

I will send some pictures as soon as I have finished and painted things, I'm having it shot blasted and powder coated in bright orange for an extra £ 60.00 quid, for that professional look.

 

[woodshop]

I will send some pictures as soon as I have finished and painted things, I'm having it shot blasted and powder coated in bright orange for an extra £ 60.00 quid, for that professional look.

Looking forward to that. Would like to see it in action... too bad you're a little too far to drive.

 

[OZDOG]

i am very impressed, you sure have done your homework and it sounds like it has paid off. i am very interested in how the bar and engine shaft are mounted , i read your paragaph on it a couple of times, but i am still not sure, from what i understand - the bar sits perpendicular to the engine shaft? I hope am not asking a stupid question, pics would be great. cheers.

 

[mickpeat]

MS880 use with Logosol mill

Just purchasd a Logosol sawmill in Norway and thinking big was better also purchased a Stihl MS880 rather the MS660 chainsaw. The problem I encountered from the start was there was no bar or chain supplied and is extremly difficult to obtain in Norway. I have since been informed that the size of bar .004, for the MS880 is not interchangable with normal stihl saws. To get to the point, I have read your article with interest and the max width of tree I plan to cut here in Norway is 22". So do you think that I have gone to big for it to be cost effective for limited sawmill use. I have not used the MS880 yet so I could easily change it for a MS660.

Kind regards
Mick Norway

 

[Railomatic]

Just purchasd a Logosol sawmill in Norway and thinking big was better also purchased a Stihl MS880 rather the MS660 chainsaw. The problem I encountered from the start was there was no bar or chain supplied and is extremly difficult to obtain in Norway. I have since been informed that the size of bar .004, for the MS880 is not interchangable with normal stihl saws. To get to the point, I have read your article with interest and the max width of tree I plan to cut here in Norway is 22". So do you think that I have gone to big for it to be cost effective for limited sawmill use. I have not used the MS880 yet so I could easily change it for a MS660.

Hello Mick

For a cutting width of 22" the 660 would be adequate using their own 1/4" chains and bar, an MS880 would not be under as much strain as the MS660, but where problems might occur is, the small 1/4" chain that the M7 runs on, would then be more suseptable to breakage if you upped the power and feed rate using the 880.

If you went for an 880, I would go for a 30" Cannon Superbar with a 325 conversion, to give more reliability over the smaller 1/4" chain.

With a bigger bar you will also be able to handle bigger trees, with their log side fastening rail system.