milling in a heat wave

[mtngun]

We are experiencing a heat wave, with temperatures above zero. In fact, this afternoon it cracked double digits. It was a great day to head to the woods and saw some boards.

Today's victim. An 18" doug fir blowdown. Lots of branches and not very straight, but beggers can't be choosers. Besides, I have almost cleaned up the fir in this patch of blowdowns, only one or two left. There's more snow on the way so this may be the last day of milling in the woods for quite a while.

Tree limbed and bucked with cancer-curing CS62. Temperature was about 5 degrees when this picture was taken. My camera battery didn't like the cold, and ceased working. The two spare batteries were useless, too. Oh, well, nothing really new here, except ...........

.......Santa came early this year and left an ENM PT15 tach in my stocking. Santa paid about $30 at a former AS sponser. For now, the tach is attached to the saw with zip ties. Hopefully I'll eventually find time to fabricate a better mount. Sorry for the fuzzy pic.

The $30 tach refreshes the display once per second, however, it seems to employ an "averaging" algorithm to filter out noise, and as a result, it takes 5 seconds for the displayed RPM to reflect what the saw is actually doing. For example, if you are running wide open and then release the throttle, the tach rpm drifts down gradually, taking 5 seconds to show a steady idle rpm.

So..... you could use the $30 tach for carb tuning if you had to, but it is not ideal for that job. I bought it to monitor RPM while milling, and for that it works fine.

A little trial and error showed that this saw/chain/log combo cut fastest around 8500 - 9500 rpm, so I adjusted the feed rate to keep it in that range.

Below 8400 rpm, power dropped off fast, and below 8000 rpm it was prone to bog.

BTW, the carb was last tuned (by tach) a couple of months ago, on a cool fall day. At that time WOT was 12,000 rpm and it sounded rich to my ear. Today, the cold dense air made the saw run a little stronger and leaner, hitting 13,000 rpm WOT, and it sounded "just right." I didn't adjust the carb because the previous tuning was conservative enough to give me a safe margin of error for days like this.

After cutting 7 slabs, the chain was getting a little dull, and the saw struggled to keep revs above 8000 rpm, so I swapped in a freshly sharpened chain, and revs went back to 9000.

A couple of cuts later, the auxilary oiler plugged up at the valve -- or more likely, the oil gelled up due to the cold -- and the saw lost some rpms. I could keep it around 8400 - 8600 but 9000 was elusive, proving that an auxilary oiler effectively boosts your power and also proving that a tach is handy on a milling saw.

BTW, all my Poulan bar oil had been thinned with 25% diesel because straight bar oil turns to jelly around 0 degrees F. The diesel worked to the extent that it was mixed well, but either I didn't mix it thoroughly, or else it separated, because I could see some 30 weight jelly as I was pouring the oil, and that's probably what plugged up the aux oiler.

Looks like I ended up with ten 2" x 12' slabs shown in the picture, plus one 8"x8"x12' post not shown. A decent day considering the conditions.

 

[carvinmark]

Good info about how the aux oiler helps RPM's. Too cold out for me to mill, I must be getting old.

 

[Andrew96]

.......Santa came early this year and left an ENM PT15 tach in my stocking. Santa paid about $30 at a former AS sponser.
A little trial and error showed that this saw/chain/log combo cut fastest around 8500 - 9500 rpm, so I adjusted the feed rate to keep it in that range.

.... proving that an auxilary oiler effectively boosts your power and also proving that a tach is handy on a milling saw.

Geez mtngun..you are hardcore. Even though it might be above freezing...that's still too much snow for me. I'm still a "crawl around on the ground too much" kind of guy. I've got two trees waiting until spring for me now.

With comments like this (above) you are certainly not helping my milling equipment project (How long do you go before you admit you have CAD?). I didn't need any more proof that an aux oiler works (though your actual numbers just mean I'll run it all the time). Mine is 'almost done' and ready to show it off with some photos. Now I read that a tach can prove usefull on a mill?
I'm a die hard 2 stoke guy, I think I'm well versed. I've raced/built/tuned many types of 2 stroke motorcycles (singles, twins, 4 cylinders) in a professional capacity and proved to be quite good at it. When an engine runs unloaded, it will either be limited by spark (I don't think my 660 has a rev limiter through the ignition), or by intake, exhaust, port flow limitations. Max power will be reached lower than this unloaded max rpm. Of course, max unloaded rpm can be damaging by many means. Now this tuning by max unloaded rpm by mixture is something new to me. However, I'm going with it, since the end result seems to be, a safe mixture at max power, working rpm, and it's quite simple to set.
Other than the use of a tach to set an unloaded max rpm...why...with respect...do I need one on my milling saw? Just to come up with a number that max power is developed (you found that by feeling the cut, timing the cut)...then continue to cut with the saw running at that rpm? I'd agree that having the instrument (and a trained ear) can help to pin point problems. You had quantitative data that your chain was dull, your oiler was plugged and increased friction. All good reasons that I can see. Am I missing something?...or is that it. I'm not saying that's bad....$30 to pinpoint a problem of some kind before it causes any real damage is great.

If your $30 Santa present isn't the best for carb tuning AND milling...what is?

 

[excess650]

Diesel gels in the cold, so no surprise there. Kerosene is often mixed with diesel in cold weather to prevent gelling. I've mixed ATF with bar oil on occasion, but kerosene or diesel would be less costly.

Your observation about rpms with and without the auxialiary oiler is a bit of a surprise, so I'll have to bite the bullet and get one.

It was 20*F here this morning, and colder than I appreciate. I won't be out milling until its closer to 30*F or higher.

I milled quite a bit of DF with both chainsaw and bandmill this summer. With the CSM, its no problem. I don't care to cut it again with the bandmill.

 

[Can8ianTimber]

Geez mtngun..you are hardcore. Even though it might be above freezing...that's still too much snow for me.

F verses C. in double digits is still way below freezing. That snow is not melting.

Way to go on milling in the cold though. You can't always wait for good weather. I was milling in a back yard last weekend and it was a couple deg below freezing, just enough to freeze the ground and make it so I did not mess the grass up anymore than it already was.

 

[mtngun]

Other than the use of a tach to set an unloaded max rpm...why...with respect...do I need one on my milling saw?

What does NEED have to do with it ? :biggrinbounce2:

Reasons why I wanted a milling tach:

-- I'm trying to keep up with BobL's hi-tech CSM

-- because in a previous thread, BobL wanted to know my saw's operating rpm, and seemed shocked that I didn't know

-- Something to break the monotony of breathing 2-stroke exhaust

-- emergency carb tuning in the field (I'm comfortable tuning by ear, but a tach provides a sanity check)

-- it was only $30, so what the hey

Seriously, the tach only confirms things that I was already "sensing" by the seat of my pants. I had "sensed" the aux oiler was freeing up power, now I can quantify it. I could always "sense" when a chain was dull, now I can quantify it. I had "sensed" that this lame 066BB has a narrow operating range between not biting the wood and bogging, now I can quantify it (the lame 066BB was actually running decently in yesterday's cold dense air, reinforcing my theory that it needs more compression). Ditto for any other experiments with the saw or chain.

In other news, yesterday's fir was 93 years old, and 19" diameter at the stump. I believe similar sized dougs on the west coast would only be 30 - 40 years old ? They grow slower here because of the cooler, drier climate.

The ENM tach also has an hour meter, which logged 1.8 hours yesterday, including the cool-down idle at the end of a cut. I did 16 passes alltogether, including the initial slabbing cuts, and the logs were 12 1/2 feet long. That works out to 2400 inches divided by 6480 seconds or 0.37 inches per second. When you factor in the idling time, actual cut speed was probably closer to 0.5 inch per second. That's slow compared to what other folks have reported, but I seem to have just as many boards at the end of the day.

 

[BIG JAKE]

Mtngun what is your compression at now? I remember you put in the BB a few months back and comp was low. Wonder when baileys is getting the Wiseco piston sets in?

 

[mtngun]

I haven't checked compression recently, but I'll check it whenever I do my post-woods clean&sharpen and let you know.

I'm sure it's gained a few psi from carbon build up if nothing else, since I run rich on oil and carb adjustment. Even my 10 year old Oly has gained 5 psi in the year that I've owned it (145 psi, not bad for a 10 year old stock saw at 4600 feet). Hey, I'll take it, at my altitude the saws need a little compensation for the thin air.

I haven't asked about the Wiseco pistons, but the revised BB kit is supposed to be in around Jan 15. The revised kit has a smaller combustion chamber -- yea ! ! !

Or I may buy a Meteor piston for the OEM cylinder. However, IN THEORY, the BB kit is ideal for milling -- if they ever get the darned bugs out of it.

 

[BobL]

What does NEED have to do with it ? :biggrinbounce2:

Check

Reasons why I wanted a milling tach:

-- I'm trying to keep up with BobL's hi-tech CSM

Good one mtngun - now you need the temp gauge too!

- because in a previous thread, BobL wanted to know my saw's operating rpm, and seemed shocked that I didn't know

I hope I didn't sound too shocked

-- Something to break the monotony of breathing 2-stroke exhaust

Check

-- emergency carb tuning in the field (I'm comfortable tuning by ear, but a tach provides a sanity check)

Check

-- it was only $30, so what the hey

Check

Seriously, the tach only confirms things that I was already "sensing" by the seat of my pants. I had "sensed" the aux oiler was freeing up power, now I can quantify it.

Check

I could always "sense" when a chain was dull, now I can quantify it.

Check

Ditto for any other experiments with the saw or chain.

Check

The ENM tach also has an hour meter, which logged 1.8 hours yesterday, including the cool-down idle at the end of a cut. I did 16 passes alltogether, including the initial slabbing cuts, and the logs were 12 1/2 feet long. That works out to 2400 inches divided by 6480 seconds or 0.37 inches per second. When you factor in the idling time, actual cut speed was probably closer to 0.5 inch per second. That's slow compared to what other folks have reported, but I seem to have just as many boards at the end of the day.

Excellent work - DNAU (data nerds R us)!

My tacho refreshes about every second which makes in good for tuning.

One more reason for a tacho is it reads zero if you leave the kill switch on hence reduces the chances of saw flooding

 

[Andrew96]

Ha ha....It seems my wife has managed to alter my speach patterns over the years. Around here....I've had to replace 'want' in my vocabulary with 'need' so as to avoid the conversation about 'how much do I want it'.
All good points outlining why you wanted a tach. Now I want one....no...I "need" one.

I don't know if I'm a hardcore DNAU

Excellent work - DNAU (data nerds R us)!

But I certainly like to come to a conclusion with quantifiable data.

Mtngun, I don't really know "where the salmon meets the snake"...I assume those are rivers. I forgot you guys down there use degF. Anything positive here is above freezing. Now I know you are hardcore. Milling in snow....below freezing..on a hilltop...obviously windy since you're doing windfall trees...hope you kept your hat on.

 

[mtngun]

Mtngun, I don't really know "where the salmon meets the snake"...I assume those are rivers.

Yep

I forgot you guys down there use degF. Anything positive here is above freezing.

5F = -15C

It was a very nice day. Only problem was the rubber chainsaw boots, which were like blocks of ice. The dual port exhaust served as a very pleasant handwarmer.

We're getting some snow now, so I may be snowed out of the woods till next summer. Time to do saw maintenance and mill upgrades.

 

[mtngun]

Mtngun what is your compression at now? I remember you put in the BB a few months back and comp was low.

120 psi......:bang:

 

[deeker]

Great posts and pics guys.

Keep it coming.

Kevin

 

[Brmorgan]

120 psi......:bang:

I'd bet dollars to donuts that's the culprit if you feel like your cut times are slow. Though, I'd have to take a look at your chains too. That's probably not a LOT slower than I get with the .063 chains, but it's significantly slower than I can cut with the .050 LP chain. It's too bad the compression never really bumped up for you with that top end. What were the rings like? Normally I'd suggest throwing an OEM Stihl set in, but that won't work with the BB kit. Maybe Husky 395 rings would work? I think they're the same diameter bore.

 

[mtngun]

What were the rings like? Maybe Husky 395 rings would work? I think they're the same diameter bore.

They were the grooved rings.

There's a thread on the Baileys' forum where someone tried a different set of rings and still had low compression.

http://www.arboristsite.com/showthread.php?t=111989

The fact that Baileys is redesigning the 066BB kits with a smaller combustion chamber suggests that it's a design problem.

I'm not knocking Bailey's, to the contrary, I appreciate them developing these kits and I'm convinced they'll eventually get it right, but the fact is that it's been a bumpy road.

 

[Andrew96]

OK so your low compression is a known problem. Lets say your BB kit with the low compression gets you back to stock power at that elevation, cold temp. Isn't the tree going to be a bit harder (since it's frozen) and you really do have a decent cutting speed? I was thinking...a frozen tree must increase your cutting time.