Thread: Chainsawmill running really hot :-(

For my mill I won't be removing the brake for two reasons.

First is that when the nut came off the clutch assembly the damage done to the clutch means that it is now a bit grippy. Quite often the chain is still moving at idle and while it is not doing so with any power I don't feel comfortable inspecting the chain or insert wedges with the potential for the chain to glide past my hand. While it would not cut with enough force for me to lose a finger it could still cut me more than I'd like.

Second is that the throat of the mill is too large to be anywhere in front or behind the bar. For safeties sake the mill must be operated from the side. This mill can deal with a log slightly over 1.4m wide. When dealing with logs smaller than this there is just too much room between the mill carriage and the log. One slip or trip and it would be all too easy to come into contact with the chain.

Since I have to stop the mill to place wedges or inspect progress the discipline of putting the chain brake on before I do so is very useful. I have found that when I fail to activate chain brake before stepping between the rails it is a good sign that I am either not concentrating or fatigued. Either way such forget fullness is a good indicates a good time to have a brake, take a deep breath and if I do it again go and have a cup of tea or even stop for the day.

Finished working on reducing the lateral forces this morning and I'm not happy. Stu's Mill mark II will definitely have a four post construction. Like the Timber King Mill adds it just make sense. On the other hand it is only a chainsaw mill and I can't expect too much accuracy. As it is I think that the saw is cutting well. I think that the official kerf of 3/8 chain is 7.5mm but there is no way I'm going to get close to that without tensioning the bar. May be adding a bar support like band mills have? Probably not worth the effort.

Having said that even cutting the kerf by 0.5mm would represent a reduction of over 5%. Whether that would represent a 5% reduction in oil, time and fuel would be another matter but it would mean 5% less sawdust and around 5% more timber. Suddenly 0.5mm is looking like 10% beneifit (5% savings, 5% extra production) maybe it is worth it? If I could take from 9mm to 8mm that might represent an effective increase of efficiency of 20%. That would be cool.

Originally Posted by weisyboy

how do you know that the saw will not be removed from the mill at some stage in teh future?

You didn't read my post properly. I did say that it's very easy to design a mill without a clutch cover so that if anyone removes the saw from a mill the saw becomes inoperable and to get it to work they will have to put the clutch cover back on. If anyone cannot figure this out then I strongly agree with you about leaving the chain brake on their saw

Originally Posted by weaver

For my mill I won't be removing the brake for two reasons.
First is that when the nut came off the clutch assembly the damage done to the clutch means that it is now a bit grippy. Quite often the chain is still moving at idle and while it is not doing so with any power I don't feel comfortable inspecting the chain or insert wedges with the potential for the chain to glide past my hand. While it would not cut with enough force for me to lose a finger it could still cut me more than I'd like.

If the clutch is damaged it should be fixed, not to stop the chain at idle using the brake. Chain motion should not be routinely stopped using the chain brake - this is a way of eventually ruining the clutch and/or brake. Using the chain brake in this situation is a bit like using a handbrake to stop a car with a sticky clutch - two wrongs don't make a right. A moving chain at idle means the saw is not tuned properly - the chain should come to a dead stop - a saw that cannot stop the chain at idle should not be used.

Second is that the throat of the mill is too large to be anywhere in front or behind the bar. For safeties sake the mill must be operated from the side. This mill can deal with a log slightly over 1.4m wide. When dealing with logs smaller than this there is just too much room between the mill carriage and the log. One slip or trip and it would be all too easy to come into contact with the chain.

This is evidence of a limited mill design. If you are milling a much narrower log using a shorter bar is the way to go. As well as improved safety, using a shorter bar on a narrower log saves power, chain and fuel and the log takes less time to cut for a longer bar.

Since I have to stop the mill to place wedges or inspect progress the discipline of putting the chain brake on before I do so is very useful. I have found that when I fail to activate chain brake before stepping between the rails it is a good sign that I am either not concentrating or fatigued. Either way such forget fullness is a good indicates a good time to have a brake, take a deep breath and if I do it again go and have a cup of tea or even stop for the day.

Now that you have explained that you have so much exposed bar I would be putting the chain brake on too. But the real solution is to use a shorter bar and get the clutch repaired and saw tuned so that it idles properly.

Finished working on reducing the lateral forces this morning and I'm not happy. Stu's Mill mark II will definitely have a four post construction. Like the Timber King Mill adds it just make sense. On the other hand it is only a chainsaw mill and I can't expect too much accuracy. As it is I think that the saw is cutting well. I think that the official kerf of 3/8 chain is 7.5mm but there is no way I'm going to get close to that without tensioning the bar. May be adding a bar support like band mills have? Probably not worth the effort.

Hows your bar sag? Bar sag will also create a wider kerf and other problems if it not attended to.

i dont remember you saying to make it so i cannot be used when not on teh mill. if its so easy how is it done cos i cant think of a way.

obviously you have never whinesed why teh chain catcher is tehre. teh cahin dosent just come of in a streight line. it whipes around and with a bar that long has the potential to get the operator around teh legs. it is highyl unsafe to operate a cahinsaw without chain catcher in place.

having a long bar on will not cause any problems on smal logs. on teh lucas mill on most logs tehre is over 2' of bar exposed it takes verry little power to run the chain on teh bar if propper lubrication is used.

it would be near imposable and a pain in teh ring to put a shorter bar on a caridge mill like teh one weaver has got.

bar sag is not that bigger problem i tends to come out once teh chain is running and especialy when its pulling hard doing a cut.

any more pics weaver?

what have you done to strengthen it up.

Originally Posted by BobL

If the clutch is damaged it should be fixed, not to stop the chain at idle using the brake. Chain motion should not be routinely stopped using the chain brake - this is a way of eventually ruining the clutch and/or brake. Using the chain brake in this situation is a bit like using a handbrake to stop a car with a sticky clutch - two wrongs don't make a right. A moving chain at idle means the saw is not tuned properly - the chain should come to a dead stop - a saw that cannot stop the chain at idle should not be used.

The problem is the clutch because it wasn't doing it before the clutch fell to bits. I was kind of thinking that I needed to get it fixed so that I didn't have a damaged clutch and a damaged chain brake. Mostly I have been stopping the chain by throttling down and then easing off the mill so that the chain stops in the log. At the end of a cut I can often get the chain to stop moving by bringing the bar back into the cut and at idle the sawdust in the kerf stops the chain. Not ideal I know but if I have to stop to get the clutch fixed I'm out of action for a while.

Originally Posted by BobL

This is evidence of a limited mill design. If you are milling a much narrower log using a shorter bar is the way to go. As well as improved safety, using a shorter bar on a narrower log saves power, chain and fuel and the log takes less time to cut for a longer bar.

The right angle bracket that holds the tip of the bar is reversible. The idea being that reversed the bracket extends into the throat of the mill and then with an appropriate extension a shorter bar can be mounted to the mill. Havn't got round to testing how that works yet.

Originally Posted by BobL

Hows your bar sag? Bar sag will also create a wider kerf and other problems if it not attended to.

I thought that that was unavoidable to a certain extent. Center of the bar would sag around 3mm. When the bar goes into the log though it seems to straighten up because the surface of my wider slabs are not dished.

Originally Posted by weisyboy

any more pics weaver?

Wife and camera get back tonight so I'll post more pics this evening.

Originally Posted by weaver

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The right angle bracket that holds the tip of the bar is reversible. The idea being that reversed the bracket extends into the throat of the mill and then with an appropriate extension a shorter bar can be mounted to the mill. Havn't got round to testing how that works yet.

Good idea!

I thought that that was unavoidable to a certain extent. Center of the bar would sag around 3mm. When the bar goes into the log though it seems to straighten up because the surface of my wider slabs are not dished.

Whether it eventually straighten up or not and how quickly it straightens depends on a number of things, main one being the angle of the cutter top plates. It's important that these be filed evenly and to the same length for left and right cutters.

How dished it is depends on how wide the logs are. Narrow logs cut with the inboard side of the bar will have minimum dishing. On full width logs the full 3 mm across the slab would occasionally be apparent.

Bar sag is avoidable. If you start out level the bar will stay level. To do this you need an anti sag device like this.

Originally Posted by BobL

It's important that these be filed evenly and to the same length for left and right cutters.

At the moment I;m able to get my left and right cutters to within 0.1mm of each other.

Originally Posted by BobL

How dished it is depends on how wide the logs are. Narrow logs cut with the inboard side of the bar will have minimum dishing.

Why would the outboard side induce the bar to dish?

Originally Posted by BobL

Bar sag is avoidable. If you start out level the bar will stay level. To do this you need an anti sag device like this.

Yep I do.

On inboard and outboard cutting. When you tension a chain on the bar I generally put the tip of the bar on to a piece of wood and let the saws weight sit on the nuts of the saw through the bar, adjust the tension and then tighten the nuts. When cross cutting I can now use the either the top or the bottom of the bar without stuffing the tension. Why is it different when milling as suggested by an earlier post on this thread?

If using a mill that clamps to the bar rather than bolts on to the saw how could it possible change the tension?

I ask because I am keen to able to cut in both directions because I want to be able to cut off the bottom of a cant some of the time. Another time I would want to cut in both directions is when taking a slab out of the center of a log. 1st cut below center, 2nd cut above center, turn log, remove slab and continue to process remaining sections of log, into cants or 1/4 sawn one edged slabs.

I've just found out that you can't post on old threads

One of the last posts on Bobl's thread about his anti bar sag device had a question about whether titanium bars sag. I was going to add to the thread that they do since mine is and it does (I know that there is a word for sentences like that I wish I could remember what it is).

I'm turning my attention now to how to add an axillary fuel tank.

I think that I've got three options:

Add fitting through the saws tank wall. Attachment 123956

Extend fuel hose from saw to Auxiliary tank

Add fitting through the saws fuel tank cap.

Option one is simple but modifies the saw. If I ever want to use the saw off the mill I've got to worry about the fitting I've added.

Option two is the easiest but I'd still want to seal around the cap somehow to stop crap getting in the saws fuel tank. While I would be using the saw on the mill it wouldn't be a problem but again if I ever wanted to use the saw off the mill I'd have to make sure that the FT was completely cleaned out.

Option three is the best but how do I do it? Can I get some sort of cap off another saw or other piece of machinery that I can then put some sort of bulk head fitting through? I could all ways buy another fuel cap from a Stihl dealer but the shape of the cap doesn't lend it self to just drilling through and adding some sort of fitting.

Originally Posted by weaver

I've just found out that you can't post on old threads

One of the last posts on Bobl's thread about his anti bar sag device had a question about whether titanium bars sag. I was going to add to the thread that they do since mine is and it does (I know that there is a word for sentences like that I wish I could remember what it is).

I'm turning my attention now to how to add an axillary fuel tank.

I think that I've got three options:

Add fitting through the saws tank wall. Attachment 123956

Extend fuel hose from saw to Auxiliary tank

Add fitting through the saws fuel tank cap.

Option one is simple but modifies the saw. If I ever want to use the saw off the mill I've got to worry about the fitting I've added.

Option two is the easiest but I'd still want to seal around the cap somehow to stop crap getting in the saws fuel tank. While I would be using the saw on the mill it wouldn't be a problem but again if I ever wanted to use the saw off the mill I'd have to make sure that the FT was completely cleaned out.

Option three is the best but how do I do it? Can I get some sort of cap off another saw or other piece of machinery that I can then put some sort of bulk head fitting through? I could all ways buy another fuel cap from a Stihl dealer but the shape of the cap doesn't lend it self to just drilling through and adding some sort of fitting.

I recently saw an add on tank for stihl saws which basically screws on where your cap would. When you want to change back it just undoes and you stick the normal cap back on. I think it was on a site through ebay us, and there was an extended oil tank as well to go with it.

Originally Posted by BobL

Chain brake on a CS is designed to;
- activate on kick back - alaskan and carriage mills don't experience kickback if their noses are protected.
- prevent person cutting themselves while moving around with a running saw. This is not a problem at all for a carriage mill and is also not a problem with Alaskans if saw is started on log rails and turned off before removing from log rails.
- Finally it allows the operator to safely inspect the chain while the saw is running - NO -wait the operator cannot also do this with the chain brake on anyway - so the operator should stop the saw to do that

In short the 3 main reasons for a chain brake on a CS are either irrelevant or make no sense on an Alaskan or a Carriage mill - it's just dead weight.

The main reason for leaving the brake on a CS in a mill is because some idiot will forget to put the brake back on when they go to use the CS in the conventional manner. However, if the bolt cover plate remains firmly fixed to the mill the saw will not operate at all and the operator will be forced to reinstall the brake.

So let me get this right bob if you hit a bolt while cutting a slab or lets say a piece of pipe or a iron dropper you will not get kickback?

I have cut plenty of logs where the bar sticks out the far side of the log and if you hit something you still get kickback. To say an alaskan mill will stop this is just wrong. And you were having a go at me about safety.

I will not be removing my chain break chain catcher or for that matter the clutch cover. DO NOT get me wrong on this topic I rarely wear chaps (dont own any) Always wear good solid pants, usually wear steel cap boots, and when I dont I wear good solid leather boots, Have used my boot to see if the chain is spraying oil which I know is not a good thing But I also reject any chains damaged by hitting steel etc. and maintain both my saw and the chain to the highest possible level and thoroughly inspect the chain and bar for possible damage at regular intervals. (this meaning every few cuts when breaking in a new bar and chain and at least every tankfull of fuel with any chain which is broken in, and when sharpening, and regularly DEGUM each and every chain.)
I am also very conscious about keeping my body and appendages well out of the line of the cutting chain and will not cut if anyone is standing within about 20 feet of me in the line of cut.

To remove the chain catcher and chain brake is not only stupid but possibly suicidal. To remove the clutch cover makes this worse in my opinion. fair enough make a few small mods for increased chip clearance but remember if the chips can hit you so can the chain should it break. as Carl said he has seen a chain break and hit the operators wrist, I saw a bloke near lose his hand and to this day have a fairly severe disability in what he has left from an 090 without a chainbreak or catcher, and knew of a bloke whose son was standing opposite the cut when the chain broke and near lost his arm.

My chain brake and clutch cover will remain in place.

Originally Posted by Travis Edwards

So let me get this right bob if you hit a bolt while cutting a slab or lets say a piece of pipe or a iron dropper you will not get kickback?

That is correct - for an alaskan mill where the bar nose is held in a clamp and the bar nose is protected, kickback is non issue. I have hit plenty of things in milling around 120 logs but never experienced kick back. This is not to say that strange things don't happen in a log but whatever that is, it's not real kickback. Kick back results from a rapid change in angular momentum (turning moment) and happens when something hits or even just touches the top quarter of the nose, the chain and bar then tries to rotate out of the cut. Holding a CS in a normal usage position results in the rotation of the CS upwards with the tip of the bar rotating back towards the operator and smacking them in the head or shoulders. Operators can severely injure their face and upper body and even die.

I have cut plenty of logs where the bar sticks out the far side of the log and if you hit something you still get kickback. To say an alaskan mill will stop this is just wrong. And you were having a go at me about safety.

If the nose of an alaskan mill is properly protected (which it should be) kickback won't happen. Even if it does happen, to activate the CS brake the operators hand MUST be on the top of the wrap handle so that it comes into contact with the handle to activate the brake mechanism. If the operator's hand is not on the wrap handle the chain brake will not activate anyway. In 99% of milling operation, one hand is on the CS throttle and the other is on the mill so the brake is as useless a tits on a bull during this operation.

CS mill operations are also quite different from a naked chainsaw. If kickback does ever occur on an alaskan mill, the chances are that the operator will have their hand on the mill about 1/3 of the down the mill. This provides about 10 times more leverage than normal CS operation and should be more than enough in most cases to counteract the forces involved. The ultimate factor that prevents the saw coming out of the cut and causing any problems is mill itself. The mill rotates only as far as the uprights and then hits the log and stops. The only point where this could be a problem is at the start of the cut. This is the point where the operator can stand directly in front of the mill and direct the blade into the cut and apply maximum forward pressure to counteract any rotational force.

Finally if and when the mill does rotate out of the cut most likely thing to smack the operator is the trailing mill rail and not the bar.

Any half decent risk analysis of a convention alaskan milling operation will demonstrate that kickback represents one of the lowest risks during alaskan milling.

Now let's analyse the chain catcher situation.
In normal CS operation the CS is held with the bar vertical and out in front of the operator. If the chain breaks the sprocket pulls the chain remaining between the break and the sprocket back towards the operator and if no chain catcher is employed the chain can swing right back and hit the operator. In an alaskan mill the inboard bar clamp bolts automatically act as chain catcher - this is even further away from the operator than a conventional chain catcher and affords better safety than a catcher. It can be more of an issue for alaskan mills that do not use bar clamps but bolt direct to bar bolts. In this case the mill uprights will act as a part catcher.

For reasons I cannot understand I know some operators like to pull their mills instead pushing but the easiest place to stand is facing the top of the saw. In this case if the chain breaks a chain catcher is irrelevant because the operator has the whole body of the saw between them and the broken chain. If the chain breaks on the top of the bar the chain is squirted away from the operator anyway.

The critical factor with removing the chain brake and chain catcher is designing a mill such that when the CS is removed from the mill the naked saw is inoperable until the clutch cover chain brake and chain catcher are put back on the saw. This is not rocket science and completely feasible.

In rough order, my assessment of risks in my alaskan CS milling operations for green wood are;

1) Driving to and from the milling site. Funny how we forget about this

2) Skin cancer: you may laugh but if you mill outside this is worthy of consideration.

3) The next most dangerous thing is moving the logs, rolling logs around and setting them up on gluts using a loader. Risk minimization includes, leaving plenty of room around logs, orient the logs on slopes so they won't roll, using decent wedges to chock logs, always use two gluts and double wedge to reduce chance of rolling. Stay away from side of logs while setting up.

4) Next most dangerous is lifting logs to create a milling slope. This depends on how it is done. Using a kangaroo jack represents high risk but even a loader has risks, and placing blocks and gluts under logs is dangerous as logs can roll off gluts and crush and operator. Same risk minimization as 3)

5) Moving slabs, even though I use a loader for the big slabs they can still fall onto the operator and crush limbs and feet, back injury is another factor. Risk minimization includes, taking things easy, sliding rather than trying to lift, using knees rather than back, using a sack trolley, levers and cant hooks.

6) Preping the logs. This is cutting off the bumps and lumps, bits of limbs etc. I do this will either a dedicated 066 or my 441. These saws MUST have all the safety fittings attached to them. Full PPE including Chaps MUST be worn during this time to minimize risk. If an operator only has one saw and they have to take the saw out of the mill to do this then obviously the saw has to have all the safety features still attached.

7) Starting and ending the cuts. This is when the full bar is exposed and loose chains can fall off. This is also a whole topic in itself. Moving a running saw on and off the log represents high risk. This is why I use log rails for just about every cut. This means I can start the saw/mill when it is on the rails and I do not have then move a running saw. Same with taking the mill off the rails, let the CS idle for a minute or two and then stop the saw and move the mill. Just lifting my 32 kg saw/mill on and off the log without it even running also has a small risk.

8) Milling ergonomics. Tired operators take shortcuts and making mistakes. A comfortable milling position that requires minimum pushing and fighting the mill is important in reducing operator fatigue. This is a whole topic for discussion in itself.

9) Exhaust fumes: Standing for hours in a fog of exhaust is not going to do an operator much good in the long term. Minimization here requires things like exhaust modification and getting the wind behind the operators back.

10) Noise - obvious

11) Vibration: this depends on the saw. Old saws are still very capable of giving an operator white finger. Newer saws a better but better again are is remote throttles with soft vibration absorbing mountain bike handles or using a winch (although I don't like using winches for other reasons)

12) Using fuel: obvious

13) Lifting the log rails, my log rails are 4 x 3 m lengths of Unistrut joined by lengths of 3/8" all thread rod. There are very heavy but I think they are worth it.

Then come things like cutting your hands while filing, bug bites, splinters, chain breaking, kick back, shark attack and UFO deportation.

For dry and dusty wood, dust probably comes in around number 7) or 8)

Remember this is my assessment your assessment may be different.

Cheers

Originally Posted by BobL

If the operator's hand is not on the wrap handle the chain brake will not activate anyway.

Most of what I know re chainsaws is from what I've been taught rather than my own experience but one of the things I was taught was that the shock of a kick back should activate your chain brake. I don't know if it is true or not but it is one of the things I was taught.

I may rearrange the order of some of those risks but I don't think I would add any. Dust from dry logs is also species dependent. For example I have heard that the dust from black wood is meant to be as bad as asbestos.

PS I didn't get pics yesterday because the camera came home with a flat battery and I've only just got back from Ballarat now. Tomorrow arvo I promise.

Originally Posted by weaver

Most of what I know re chainsaws is from what I've been taught rather than my own experience but one of the things I was taught was that the shock of a kick back should activate your chain brake. I don't know if it is true or not but it is one of the things I was taught.

That is correct, it requires a very rapid acceleration of the bar nose meaning the inertial chain brake triggering will activate on a naked saw on maybe on a mini mill.
Here is a You tube demo of this happening.
[ame="http://www.youtube.com/watch?v=37xodIuufaQ&feature=related"]YouTube- Broadcast Yourself.[/ame]

BUT the extra mass of an alaskan mill and fact that part of the mill it is attached to the bar nose, means this is less likely. The bar nose just cannot accelerate fast enough to activate the brake. I still have the chain brake on my 880 that I use for milling and it has never gone off but that doesn't mean it will not happen on lighter weight mills. Carriage mills are even less likely to do this.