The Forestry Forum

General Forestry => Chainsaws => Topic started by: Jim_Rogers on May 20, 2013, 04:02:07 PM

Title: Chain length, bar length, drive links, questions
Post by: Jim_Rogers on May 20, 2013, 04:02:07 PM
Ok, so a few years ago, I bought a husky 450 rancher chain saw.

I thought it was a regular 16" bar.

After a while I needed another chain and took the one on it down to a store to have it ground as it needed it bad to get everything lined up again. While there, I bought another chain to put on the saw to keep going.
Some how I lost that box.

I was trying to figure out and find another chain to replace the first one, so I'd have two, one on and a back up one just in case.

I took the first one and I counted the drive links, there were 72 of them. I thought that's how you make sure you get the right length chain.

Then I measured the bar, just the part sticking out of the saw, and sure enough it was 16" long.

Knowing that I was going to go to the logging equipment show in Bangor, Maine, where for sure there would be a chain saw dealer or two, I took the extra, old, dead chain with me to make sure I'd get the right one.

Well, I got out of my truck in the parking garage to walk up the hill to the show and completely forgot about putting the chain in my tote bag.

When I got to a dealer, I asked him if he had a 72 drive link chain for a Husky 16" bar. He told me that 72 drive links were for 20" bars. I said it all depends on how you measure the bar, doesn't it.
He said you only measure the part that's sticking out. I said ok well that's what I did and it was 16".
My friend and I looked up online and found out that the size should be .325 for the pitch of the bar groove. At least I think that's what the .325 is for, but if not then educate me.

So I told this dealer I needed a 72 drive link chain, with the .325 size. And he said it was for a 20" bar and that it was too long for my 16" bar. I told him that's all I know and I want one like that.
He sold me one. 72 drive links and .325.

Sunday, my mechanic came over to talk about the next things to repair, and I started asking him about chain saw bars and how to measure them.
He said that the size of the bar was stamped on the bar, under the clutch cover.
So we got out a bar wrench and took the cover off and cleaned up the bar and sure enough there was a stamp there saying point 325 and it also said 18".

I was totally confused. The whole bar measures from end to end 20". The part that sticks out is 16".
The chain I got matches the chain on the bar with 72 drive links.
So bottom line is I got the right chain I needed.

But what's up with this measuring the bar thing?

Where do you measure your bar?

Why is mine sticking out 16", says 18" and is 20" long end to end?
I measured it to see where the 18" comes to and it doesn't line up with anything on the bar, not the hole for the bolt or the slot for the adjustment or anything.

I really don't understand this at all.

Any advice or education would be helpful and appreciated.

Sign me "confused"

Jim Rogers
Title: Re: Chain length, bar length, drive links, questions
Post by: petefrom bearswamp on May 20, 2013, 06:47:21 PM
Boy Jim
You got me.
I ve never paid attention to length, just took the old chain with me when buying a new one.
Title: Re: Chain length, bar length, drive links, questions
Post by: sawguy21 on May 20, 2013, 07:35:19 PM
Bar length refers to the amount that is actually exposed to the cut, not the overall length. A 16" bar normally requires 66 drive links with .325 chain, Stihl is 67 but they gotta be different. 72 indicates an 18" bar. The dealer is correct if you had 3/8" chain. Thoroughly confused yet?
Title: Re: Chain length, bar length, drive links, questions
Post by: Al_Smith on May 20, 2013, 08:13:14 PM
It's an 18" which takes 72 drivers of .325 .72 drivers of 3/8" would be a 20" .
Title: Re: Chain length, bar length, drive links, questions
Post by: bill m on May 20, 2013, 08:50:41 PM
To measure the max. possible cut you need to measure from the tip of the bar to the edge of the clutch cover or body of the saw. Some saws it is the same on both sides of the bar but on some the clutch cover sticks out more. Don't measure to the dogs, some saws don't have them.
Title: Re: Chain length, bar length, drive links, questions
Post by: beenthere on May 20, 2013, 08:54:15 PM
It's an 18" which takes 72 drivers of .325 .72 drivers of 3/8" would be a 20" .

+1
Title: Re: Chain length, bar length, drive links, questions
Post by: thecfarm on May 20, 2013, 08:59:51 PM
I ran an 18 inch bar and 72 drivers. I never measured my bar,I just know it's an 18 incher.
Title: Re: Chain length, bar length, drive links, questions
Post by: beenthere on May 20, 2013, 09:38:19 PM
And you know it is .325......  ;D
Title: Re: Chain length, bar length, drive links, questions
Post by: Jim_Rogers on May 21, 2013, 08:04:54 AM
Thanks for all your replies, and information.

Jim Rogers
Title: Re: Chain length, bar length, drive links, questions
Post by: CTYank on May 21, 2013, 10:31:49 AM
To identify a chain, you need the following:
1. Pitch- the distance between the centers of three rivets, divided by two. E.g. 3/8"
2. Gauge- thickness of drive links. Must match bar groove. E.g. .050"
3. # of Drive Links- self explanatory.
4. Type (chassis). E.g. "low-profile", "narrow-kerf"
5. Cutter type- shape of cutters. E.g. "chisel", "semi-chisel", "chipper"

Pitch must match that of sprockets- nose and drive.
Gauge must match that of bar groove, with some clearance.
#DL must suit bar length.
Chassis type must match bar/sprockets. 3/8" low-pro not interchangeable w/3/8"
Cutter type- best to match to work. I.e. "semi-chisel" for dirty, "chisel" for clean wood.

There are of course other variations, affecting function, but not usability.
Most important variation w/chains is EDGE. Must be SHARP, w/consistent angles.
Title: Re: Chain length, bar length, drive links, questions
Post by: Jim_Rogers on May 21, 2013, 10:35:37 AM
Thanks for all your replies, and information.

Jim Rogers

x2
Title: Re: Chain length, bar length, drive links, questions
Post by: beenthere on May 21, 2013, 11:17:08 AM
Quote
Why is mine sticking out 16", says 18" and is 20" long end to end?
I measured it to see where the 18" comes to and it doesn't line up with anything on the bar, not the hole for the bolt or the slot for the adjustment or anything.

I really don't understand this at all.

Any advice or education would be helpful and appreciated.

Sign me "confused"

Jim Rogers

So Jim, what do you have on your saw?   Anxious to know.
Title: Re: Chain length, bar length, drive links, questions
Post by: Jim_Rogers on May 21, 2013, 11:34:19 AM
I have a bar that says 18" on it, is 20" over all length and sticks out 16". It takes a .325 chain with 72 drive links.
I don't know the gauge yet, I don't know the type yet. And I don't know the cutter type, yet.

All I know is, that I think I got a chain that will fit. But I haven't tried to put it on, yet. ;D

Jim Rogers
Title: Re: Chain length, bar length, drive links, questions
Post by: MEloggah on May 21, 2013, 06:25:49 PM
you have an 18" bar sir. what you measure off the crankcase (inches of exposed bar) don't mean didly squat. FYI, you wont get 18" of cut from an 18" bar & chain. it would be more like 17" +/-.

for example, my 372's/385's  w/ a 20" bar measure roughly 19inches of cut.
Title: Re: Chain length, bar length, drive links, questions
Post by: beenthere on May 21, 2013, 07:04:31 PM
MELoggah
Sorry to slightly disagree, as you sound like you know a lot.  ;)
But I have an MS361 Stihl, 20" bar, stamped 20", 3/8 chain, and there is near exactly 20" of bar ahead of the case. A bit more of actual cut because the teeth come around the end of the bar for more cut.
Then figure in the travel of a bar with the adjusting screw may move the distance over an inch +/-

As long as Jim has his answer, we should be good with it. :)
Title: Re: Chain length, bar length, drive links, questions
Post by: MEloggah on May 21, 2013, 07:19:02 PM
why I said plus/minus ;) each saw/model seems to be slightly different. our old 262's with 20" bars give me 20 1/4 and my new 372's are much less then 20.  and an 18 on the same saw is 17.5"of cut. since we only run husky I shouldn't have guessed about the amount of cut. my bad :)