Re: Was chain sawing a dead Monterey Pine today & had a few basic questions

On Mon, 29 Sep 2014 21:25:04 +0000 (UTC), "Danny D." wrote as underneath :

So what is the difference between the kerf width of the three chains? I doubt that a few thou would start catching on the chainsaw body unless the body clearances are tighter than they should be on any chainsaw. You may get accelerated wear on the bar rails if you tend to tilt the bar in the kerf with the wider chains. But the chain you got should be usable in my guestimation, just try to keep the bar straight in the cut. C+

Charlie+ wrote, on Tue, 30 Sep 2014 08:06:29 +0100:

These are good questions.

All I know is the difference in cutter is a few thousandths.

How many? Vic said he didn't know, but when I had pressed him, he said not more than 5 or 10 thousandths.

When I pressed him on how that would damage the bar with the thinner rails, he said that that's what they tell him.

So, I have had three (3) customer service personnel tell me the same thing - but not one of them can tell me why.

One of my saws, a small Stihl, has a 14 inch bar and is aimed at homeowners who want to cut up small stuff. It uses an anti-kickback chain made for infrequent users, folks who don't have much experience with chain saws and how to use them. The part of the chain that fits into the bar is about .005" thinner that normal chain. So even though there is a chain that has the same pitch and so on it will not fit easily into this bar. I was able to find a more aggressive chain than the stock one but the better chain for lots of cuts won't fit in the bar so I will be buying another bar for this saw because it gets lots of use. I imagine your chains are the same. I can push the thicker chain into the bar but it drags so much that the bar would overheat quickly. I suppose I could put the chain in with some lube and run it slowly and eventually wear the bar to fit but I'm just gonna buy another bar. I'll get a 16 inch bar because the Stihl dealer says that a 16 inch bar is really the longest bar the saw can pull and still cut fast. Eric

On Tue, 30 Sep 2014 08:51:35 -0700, snipped-for-privacy@whidbey.com wrote as underneath :

OP said all three chains were .050 so this is not useful, an extra .005 would be a major difference. I wouldnt dream of force using a .055 chain in a .050 bar. asking for a jam and superfast sprocket wear. C+

Note how many different types of 0.325 pitch chain is available.

I suggest you buy or download the Oregon "Maintenance and Safety Manual". Lots of good info that might keep you out of trouble: I'm not sure where to get the printed version. I forgot where I stole my copy.

For your amusement:

etpm wrote, on Tue, 30 Sep 2014 08:51:35 -0700:

According to my three phone calls (two to Oregon, and one to Husqvarna), there are four (4) dimensions that matter when matching a chain:

1. pitch (distance between three rivets divided by two), e.g., 0.325"
2. gauge (thickness of the part that goes into the bar), e.g., 0.050"
3. # drive links (number of parts that go into the bar), e.g., 72
4. width of cutter (e.g., narrow kerf or standard kerf), e.g.., G72 vs H72

Charlie+ wrote, on Wed, 01 Oct 2014 07:34:33 +0100:

True.

The amazing thing is that all three customer service personnel insisted that *damage* could result to the bar, even though the two chains in question, namely the Oregon H72 versus the Oregon G72, all have the same three primary dimensions of pitch, gauge, and number of drive links (as do the Husqvarna H20 and H30 chains).

They all said there are four (4) dimensions that must be matched!

1. pitch (distance between links)
2. gauge (thickness of the part that goes into the rail)
3. drive link number (determines the length of the chain, with pitch)
4. kerf width (a major determinant of the power needed to cut & kickback)

REFERENCES: Vic of Oregon @ 503-653-8881 Becky of Blont International @ 800-223-5168 (aka Oregon 3rd-party repair) Keisha of Husqvarna @ 800-487-5951

Jeff Liebermann wrote, on Wed, 01 Oct 2014 01:23:46 -0700:

That looks like my Husqvarna 445!

Did you have a photo of the 7-tooth spur type sprocket?

I had accidentally used a 62-drive-link 18" chain (instead of a 72-link

Jeff Liebermann wrote, on Wed, 01 Oct 2014 01:23:46 -0700:

That link explained the four (4) types of kerfs:

1. Chisel Kerf
2. Narrow Kerf (Must Be Matched with Narrow Kerf Bars!)
3. Semi-Chisel
4. Skiptooth Versions

Notice that, even though the pitch, gauge, and number of drive links are the same, the "narrow-kerf" chain (#2 in the list) must be used with the narrow-kerf bar (which is also called the "micro-lite" bar), which has the same depth of slot and the same width of slot, but which has thinner rails.

What I can't fathom is *how* the outer part of the chain can damage the bar, since the part that fits into the bar is the *same* gauge!

For example, the 18" "standard" Oregon H72 chain is what I had been told at Lowes to buy, but, the correct chain for my Husqvarna 445 (also from that Lowes store) is the 18" Oregon G72, both of which have the same pitch, gauge, and number of drive links:

Jeff Liebermann wrote, on Wed, 01 Oct 2014 01:23:46 -0700:

The strange part about that link is this sentence: "This chain will not work well with standard chainsaw bars, so you will need to match your chain with a narrow kerf bar..."

Given, AFAWK, the only difference with a narrow-kerf bar from a standard bar is (reputedly) the thickness of the rails, two strange questions must result from that information:

1. *Why* does a narrow-kerf bar have thinner rails than a standard-kerf bar, when the kerf is *outside* the rails?
2. How can they say we must *match* the chains to the narrow-kerf bar, when the parts that goe into the bar (i.e., the drive links themselves) are exactly the *same* in both cases?

(e.g., the gauge, which is the part inside the rails) is the *same* on the standard 0.050" gauge Oregon H72 and the narrow-kerf 0.050" gauge Oregon G72 chains)

Makes no sense, to me, but, three people (who should know) confirmed this.

Jeff Liebermann wrote, on Wed, 01 Oct 2014 01:23:46 -0700:

I called the number at that reference 707-984-8115 but it is 3am in California and only 6am Eastern, so the "answering service" took down my question and someone will call me back at 9am Eastern (6am my time) to answer my question of:

Q: How can a standard-kerf chain possibly damage a narrow-kerf bar?

Jeff Liebermann wrote, on Wed, 01 Oct 2014 01:23:46 -0700:

Wow!

That's the least expensive I've *ever* seen an 18" chain go for!

The "Woodland Pro" brand chain is only $13 (free shipping too). "CHAIN = WoodlandPRO 18" Chainsaw Chain Loop (20NK-74 Drive Links) This chain is designed to run *exclusively* on narrow kerf bars."

Here's the blurb: "20NK will fit saws using Oregon 95VP series and Husqvarna H30 chains. 20NK will not perform well unless matched with a narrow kerf bar. 20NK chain sharpens with a 3/16" round file or 1/8" grinding wheel. Chain manufactured in the U.S.A. by Carlton."

The only problem is that it's *not* a low-kickback chain!

I'll take a guess :)

When a tooth is cutting there is force applied toward the bar, thinner bar less able to resist that force. The greater the tooth bite, the greater the force. Ditto for any lateral motion.

dadiOH wrote, on Wed, 01 Oct 2014 06:43:15 -0400:

This makes sense.

I think the reason for the thinner rails (hence thinner bar) is that the narrow kerf chain cuts a narrow kerf so the bar itself must be thinner in order to have the same clearance inside the wood.

So, in effect, the thinner bar isn't there so much as to accommodate the "chain", but, I think, as to accommodate the thinner cut in the wood.

Maybe ?

Mike Marlow wrote, on Wed, 01 Oct 2014 07:30:42 -0400:

I don't know if it matters, or not, because I have never used a non low- kickback chain before.

I don't know when "kickback" kicks in. For example, it didn't kick in when I was cutting this dead Monterrey Pine this weekend:

Some of those Monterrey Pine logs are wider than the 18 inch chain, so, I had to "girdle" them to cut them fully through:

AFAIK, the saw never "kicked back" on me, but, I'm using a low-kickback chain. Would a high-kick-back chain have handled it differently?

The term refers to when the operator touches the tip of the bar to the wood.

Because of the harsh curve there, the cutting teeth are more exposed. It's possible for the bar to come flying back at you. Can be dangerous or lethal.

. Christopher A. Young Learn about Jesus

Could you explain how to use the IFR and Bird to tune the chain saw ? I have a Bird and 8924c I could use on mine. (GRIN)

first, you have to get that chain saw moving REALLY fast.

It's a Husqvarna 136. My guess is about 25 years old. I got it in a trade for some repair work because it needed a new carburetor. Some cleaning and adjusting solved that problem. The repair job in the photo was just the fuel line. I got tired of replacing it and replaced it with a thicker equivalent. In order to make it fit, I had to enlarge the hole in one of the plastic parts. The required tearing it down to what you see in the photo. It was also useful for cleaning out the oily sawdust from odd corners. A simple job that ended up taking about 5 hrs work.

The engine is very different. The 445 is a reduced emissions X-torq machine which is quite different from my old 136:

That looks brand new. The sprocket doesn't have the tradition gouge down the middle from the drive links. I have a fair collection of chains for each saw (I think I have about 6 saws), each with its own matching rim sprocket. If you're not a heavy user (i.e. not doing logging) you probably don't need to go to such extremes. However, I like to use my chains well past the traditional point where they should be recycled, so matching the wear is required.

Incidentally, Bailey's is for professional loggers. They know just about everything there is to know about using chain saws for logging, but are not terribly interested in homeowners. Locally, you might try giving Webb's a visit:

Something is wrong with that picture. You're suppose to have bar lube and grease just oozing out of the bar and chain. It looks dry to me.

My take on the narrow kerf bars and chains is that if you don't lube them properly, the reduced contact area between the chain and bar will ruin both somewhat faster than a standard bar and chain. I have a few narrow kerf bars in my pile that I traded out with owners because of this problem. I plan to grind the bars flat again, but haven't had the time or interest. Oddly, I've never bothered to compare the normal and narrow kerfs cutting abilities. These days, I just hire the locals to do my tree work for me. I'm getting too old for this type of exercise.