# Milling and saw destruction



## Walt41 (Aug 4, 2010)

I have been thinking about purchasing a small mill to cut boards for a few projects. It seems to me that milling is a death sentence for saws due to heat, the death can be slow or fast but, it is still death.

My question for those smarter than me is threefold:

1) Has anyone come up with a better cylinder design, possibly with bigger fins for extra cooling when milling?

2) Has anyone experimented with any type of auxiliary cooling, possibly liquid or Nos? I've seen the Nos thing on race cars and think it might work if the delivery system could be worked out.

3) Why do saws not have a temp gauge?


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## Taxmantoo (Aug 4, 2010)

You want head temp? 12v power source might be a difficulty:
http://www.egauges.com/vdo_mult.asp?Type=Cylinder_Head_Temp&Series=Cockpit&Units=E


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## smokinj (Aug 4, 2010)

Best just to keep on top of all the little things.
1. sharp chain
2. air filter clean
3. saw clean
4. aux oiler http://www.baileysonline.com/itemdetail.asp?item=46801&catID=
5. idle for a min or two through big cuts
6. chain tightness I now run much loser than I would cross cutting probally in the 1/2 inch of slack range.
7. I am sure there is more but thats a good start.


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## chuckwood (Aug 4, 2010)

*heat*



Walt41 said:


> I have been thinking about purchasing a small mill to cut boards for a few projects. It seems to me that milling is a death sentence for saws due to heat, the death can be slow or fast but, it is still death.
> 
> My question for those smarter than me is threefold:
> 
> ...



1. I'm not aware of any chainsaw on the market specifically designed for milling, there's just not enough of us out there to make a market. 

2. The primary problem with this type of tinkering is the added weight. Once you've tried slinging around a 36" Alaskan with a 100+ cc saw, you'll understand that weight issues are critical. The best things to do to combat heat is to run with a richer mixture than stock, open up the exhaust a bit, let the saw idle between runs and before shutting off, and be sure there's no sawdust clogging up the inside areas of the engine. Routinely take off the covers and blow the dust out. I've not burned up a milling saw yet (knock on wood!)


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## mtngun (Aug 4, 2010)

Walt41 said:


> Why do saws not have a temp gauge?


BobL and BillSteuwe have fitted a temperature gage to their milling saws. Looks easy enough to do.

Yes, milling with a chainsaw is a high-maintenance activity. A bandsaw is light years more efficient. If owned timber, I would definitely want a bandsaw.


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## smokinj (Aug 4, 2010)

mtngun said:


> BobL and BillSteuwe have fitted a temperature gage to their milling saws. Looks easy enough to do.
> 
> Yes, milling with a chainsaw is a high-maintenance activity. A bandsaw is light years more efficient. If owned timber, I would definitely want a bandsaw.



+100 on the high-maintenance chain alone will keep you busy, but thats part of the charm for me.


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## BobL (Aug 4, 2010)

Walt41 said:


> I have been thinking about purchasing a small mill to cut boards for a few projects. It seems to me that milling is a death sentence for saws due to heat, the death can be slow or fast but, it is still death.



I disagree, there are folks on AS and elsewhere who have run CS mills for many years without problems. I Know a fellow in Queensland who mills 3-4 logs a year with his trusty 07S and has done so for more than 30 years. The problem is usually that a milling saw needs to be better maintained than a firewood saw that bounces around in the back of a truck, gets fed year old gas, and gets tuned up once a year if its lucky. 



> My question for those smarter than me is threefold:
> 1) Has anyone come up with a better cylinder design, possibly with bigger fins for extra cooling when milling?


More or bigger fins are not going to assist much or at all. Some deaths from heat related events usually happen so quickly that bigger fins will not remove enough heat quickly enough, eg to defend a saw against a crankcase leak or poor tuning. Its far better if operators pay attention to tuning and not overload sawswith blunt chain. 



> 2) Has anyone experimented with any type of auxiliary cooling, possibly liquid or Nos? I've seen the Nos thing on race cars and think it might work if the delivery system could be worked out.


Liquid cooling adds too much weight to saws to retain portability. If portability is not an issue then a nice low revving 4 stroke motor is a far better option for a mill - there are plenty nice 4 stroke motors in the 15 - 30 HP range that are already used in slabbers or bandsaw mills.



> 3) Why do saws not have a temp gauge?


Temp gauges are just something else that can go wrong, but it is very easy to fit a gauge if you wish.


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## huskyhank (Aug 4, 2010)

+1 on what BobL wrote.

And I'll add that if you just want a few boards you can take your logs to a sawmill and save yourself a lot of work.

I consider chainsaw milling something that I do to get wood I can't get any other way. For 2x4s I'm headed to the lumber yard.


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## bobsreturn (Aug 4, 2010)

theres a good chance with a properly maintained saw the operator will wear out first :jawdrop: or find something easier to do with their time the logs i get are a long walk and portability is needed , otherwise i use my lucas saw . cheers Bob


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## kugss (Aug 5, 2010)

When i built motocross engines we use to put temp stip stickers on the cylinder. Pretty good sticker very neat item.
http://www.motosport.com/dirtbike/p...TICKERS-3-PACK/?catalogId=110448&usersearch=1


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## BobL (Aug 5, 2010)

kugss said:


> When i built motocross engines we use to put temp stip stickers on the cylinder. Pretty good sticker very neat item.
> http://www.motosport.com/dirtbike/p...TICKERS-3-PACK/?catalogId=110448&usersearch=1



The problem with these strips is that they cannot be put located enough to the spot where the typical heat problems arise (just above the exhaust manifold. Even if they could be placed there they would be hidden by shrouds etc.


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## Hillbilly3995 (Aug 5, 2010)

I assume you're talking Nitrous Oxide when you say Nos?

If so, its on the drag cars for boosted horsepower and increased RPM's
its an accelerant injected into the plenium or straight into the CC to increase power
no help on cooling...It will make you FEEL cool if your'e in the dentist chair...
(its also a sedative/anesthetic when inhaled, laughing gas)


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## mdavlee (Aug 5, 2010)

He probably ment a system to fog the cylinder fins to help it cool down some. I'm sure he didn't mean inject it into the carb or intake. Some drag racers use it to fog the intercooler on a turboed rig to cool intake temps down.


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## Walt41 (Aug 5, 2010)

Nos hits at -128 below zero, so I was thinking of it's cooling properties. I still think there is a better cylinder design out there, possibly fins of another material that dissipate heat faster


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## smokinj (Aug 6, 2010)

Walt41 said:


> Nos hits at -128 below zero, so I was thinking of it's cooling properties. I still think there is a better cylinder design out there, possibly fins of another material that dissipate heat faster



I have ran in 90+ heat I am sure nos would have helped....But at what price!
keep it as simple as possiable and the little things taken care of and really never had an issue if they are taken care of. You can only push the saw as hard as the chains will let you so the saw has time to cool down.


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## BobL (Aug 6, 2010)

Walt41 said:


> Nos hits at -128 below zero, so I was thinking of it's cooling properties. I still think there is a better cylinder design out there, possibly fins of another material that dissipate heat faster



The temperature is largely irrelevant, what's critical to remove heat is the specific heat capacity of the material. NOS has a lower heat capacity than air (a mix of N2 and O2). Water has by far the greatest heat capacity of any material but don't forget water in contact with a hot cylinder turns to steam and that only has a heat capacity of about twice that of air. Given the complications of carrying and spraying water on a CS it's easier to just up the air flow across the engine.

To illustrate the above, a lab assistant I know was working in a laboratory where the air con was not working so he decided to release some Liquid Nitrogen (-320F) into the room to cool it down. He released about a half a gallon of the stuff which quickly evaporated making a pleasantly cool gas that only lasted for a few minutes but then the room was just as hot as before so he decided to release more. After he release about 5 gallons of the stuff it still didn't seem to make any significant difference so he release another 5 gallons - no difference. Now he started feeling dizzy because he had changed the O/N ratio in the lab and was in danger of asphyxiating himself, fortunately he had the sense to leave the lab and was OK. Just because it's cold does mean it has much of a cooling effect. In the opposite sense have you seen the mythbusters quickly stick their fingers into a bath of molten lead and not suffer any significant effects?

There are only 3 metals that have a superior thermal conductivity than ally, and they are silver, copper and gold, all of which would add significant weight to the engine. All alloys made have intermediate thermal conductivities so there is nothing that will be better than silver. Even if weight or cost was not a problem you don't see any of these used in superbikes or exotic type engines. You just need to talk to old timer engineers or backyarders and they will tell you there is very little left to be discovered in engine technology.


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## Walt41 (Aug 6, 2010)

Bob, what If the case of the saw was more heat passive? BTW, I agree with your thoughts on the back yarders and old timers.


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## BobL (Aug 6, 2010)

Walt41 said:


> Bob, what If the case of the saw was more heat passive? BTW, I agree with your thoughts on the back yarders and old timers.



What do you mean by passive? Do you mean 
a) able to operate at higher temperatures? 
b) somehow store the heat? 
c) dissipate the heat?
OR?


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## Walt41 (Aug 6, 2010)

I was thinking dissipate heat.


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## BobL (Aug 6, 2010)

Walt41 said:


> I was thinking dissipate heat.



The body of most metal saws already dissipate some heat but the effectiveness of adding extra metal on top of existing fins is minimal. Cooling fin technology (developed for many uses from aircraft through to computer chips) is well understood and pretty well optimized on most devices. Most of the heat dissipation in fan cooled fins is achieved by the inner half of the fin so making the fins longer or adding more metal for the heat to dissipate into doesn't help as much as one might think. Adding an extra inch to all the cooling fins on a saw will not save it from being constantly overloaded by a blunt chain, or being run with a crankcase leak, or bad tuning where the air fuel mix inside the cylinder just gets too hot locally too quickly for the P&C to handle. You'd be better off going to ceramics or other exotic alloys but these approaches are not the way to solve bad maintenance or servicing issues.

BTW there is something else that transfers heat extremely well and that is diamond and they are used to coat fancy microprocessor chips. But even coating the fins on a CS with these would not prevent the overheating that kills saws.


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## huskyhank (Aug 6, 2010)

I think the answer is careful tuning and monitoring.


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## smokinj (Aug 6, 2010)

"these approaches are not the way to solve bad maintenance or servicing issues".

There the answer these things take a lot of that be prepare for all the little thing and the big thing will be good. I was running the chain a little tight and the veggie oil was boiling on the bar......check eveything often.


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## Timberframed (Aug 6, 2010)

Remember that internal combustion engines are designed to run at their operating temps. Too cool and your going to have more problems than you wished for. If concerned of overheating, mount a small but powerful fan on your mill frame. Inconvenient indeed but it will take a lot of the heat off.


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## jimdad07 (Aug 6, 2010)

A well tuned saw, very sharp chain, aux oiler and letting the saw idle to cool in between cuts. The easier the saw cuts, the longer it will last.


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## BlueRider (Aug 7, 2010)

I'm one of those that Bob was refering to about having a saw that has seen a lot of use milling. Up until a couple of years ago my main milling saw was an 051. I started milling with it in 1994 and the saw still runs as strong as ever. The only reason it is no longer my main milling saw is because I picked up a slightly newer 051 and converted it to an 075. to add insult to common sense I have always run 50:1.

What no one has touched on is the idea of trying to avoid as much heat as possible. the 051 and 075 both have the exhaust exiting the top of the piston with the muffler being mounted on the side of the saw. the 066,084, 395, 3120 etc all have the exhaust exiting out the front of the piston and the muffler mounted on the front. this causes the heat to bounce off the log and back into the saw. Bob did an excelent job of addressing this on his 088. (Que Bob posting a link to apropriate thread here)I would look to doing a similar mod on anything other than an old long stroker.


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## Hillbilly3995 (Aug 10, 2010)

mdavlee said:


> He probably ment a system to fog the cylinder fins to help it cool down some. I'm sure he didn't mean inject it into the carb or intake. Some drag racers use it to fog the intercooler on a turboed rig to cool intake temps down.



No they don't, they may install the fogger IN the intercooler, they use ice for cooling, some even freeze salt water. nobody is introducing their very expensive N2O to the atmosphere for cooling. an intercooler is basically a radiator to cool the intake air because the turbo causes a lot of heat to be induced (compression and transferred heat from the drive side).
They are using N2O INSIDE the IC for the performance enhancement I mentioned.
The spray bar is sometimes called the fogger, but nevertheless the N2O is going to combustion NOT passive cooling.


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