The Forestry Forum

General Forestry => Chainsaws => Topic started by: kellysguy on May 28, 2015, 11:49:49 PM

Title: If 3/8 takes more power
Post by: kellysguy on May 28, 2015, 11:49:49 PM
then why do manufactures use it on small saws? I noticed Echo uses 3/8 on everything. If it takes more power to run a 3/8 chain then why use it on a 30cc saw? Is it a production cost thing?
Title: Re: If 3/8 takes more power
Post by: so il logger on May 29, 2015, 01:08:32 AM
I wasn't aware echo uses 3/8 on everything. Pretty sure they don't, as I have had one that was .325 Put a .404 on a 70cc saw and you will understand  :) More pull via chain weight and more tooth contact will rob power out of a already smallish saw.
Title: Re: If 3/8 takes more power
Post by: starmac on May 29, 2015, 03:21:46 AM
From what I understand, what is used is a 3/8 low profile, whole different animal from regular 3/8. I could be all wrong though.
Title: Re: If 3/8 takes more power
Post by: LeeB on May 29, 2015, 04:18:55 AM
Echo's website offers 3/8 and .325 chains. I don't see any other sizes listed.
Title: Re: If 3/8 takes more power
Post by: ladylake on May 29, 2015, 05:28:00 AM
Echo uses 3/8 low pro on their saws up to 40 cc and they really cut , the big difference is they use a 6 tooth driver.  I tried a 7 tooth which cut quite a bit slower than the 6 tooth.. The 45 to 50 cc saws will have a .325 7 tooth and the 60 and above will have regular  3/8 with a 7 tooth driver.  Steve
Title: Re: If 3/8 takes more power
Post by: kellysguy on May 29, 2015, 08:34:22 AM
There was a major suppliers site that showed the "recommended" chain for all echo models from 310-590 as 3/8 which is where the statement comes from. I want to say it may have been a box store but I could be wrong.

So then I take it that 3/8 LP has less drag than .325, is that correct?
Title: Re: If 3/8 takes more power
Post by: SawTroll on May 29, 2015, 10:50:56 AM
Drive sprocket size is a major factor here, but the end result also depends on exactly which chain models are involved
Title: Re: If 3/8 takes more power
Post by: kellysguy on May 29, 2015, 12:20:09 PM
Drive sprocket size is a major factor here, but the end result also depends on exactly which chain models are involved


I understand that completely, with all things being equal are the 3/8LP the easiest to pull? (excluding 1/4 of course).
Title: Re: If 3/8 takes more power
Post by: Philbert on May 29, 2015, 01:16:09 PM
'3/8' is the pitch - the average distance between the rivets in the links.  It does not determine the height, width, shape, or size of 'bite' of the tooth.  As noted, 3/8 low profile is really a different animal than full sized 3/8 chain, as they don't even use the same sprockets.

In terms of power required to pull a chain, I think of this sequence (low power required to high power required):

1/4", 3/8 low profile AND narrow kerf (e.g. Oregon type 90), 3/8 low profile (e.g. Oregon type 91), .325 narrow kerf (e.g. Oregon type 95), .325", 3/8", .404".

Of course, there can also be some differences between manufacturers of the same size chain; if the chain is full-chisel vs. semi-chisel, how it is sharpened, etc.  Saw manufacturers will also use skip tooth, and semi-skip tooth spacing to sometimes put larger pitch chain, or longer bars, on lower powered saws.  This is somewhat deceptive in my opinion, but legal.

Philbert
Title: Re: If 3/8 takes more power
Post by: HolmenTree on May 29, 2015, 05:35:43 PM
3/8 LoProfile chain or Picco as Stihls trademark is actually  an extended pitch 1/4" chain made into 3/8" pitch. Oregon introduced  it as a manufacturing cost saving consumer  chain  in 1975. Stihl Picco in 1979.
Less pieces per foot was the savings.
Before 1976 the 1/4" chain was outfitted on all small cube saws as the preferred  chain . But many more pieces per foot make it an expensive  chain to manufacture as todays prices of 1/4" chain proves.
This chain cuts a narrower kerf over the larger chains and has a smaller bite with it taking a 5/32" file.
As said a 6 tooth spur drive  sprocket  as a " lower gear" helps the little saw powerwise too .
Title: Re: If 3/8 takes more power
Post by: kellysguy on May 29, 2015, 08:36:13 PM
Thanks guys, I really appreciate it. I finally got them both together and can see the difference now. Man that LP is small. I'm surprised how well it cuts but it makes sense on such a small saw.
Title: Re: If 3/8 takes more power
Post by: HolmenTree on May 29, 2015, 09:05:59 PM
Now I'll  make things really confusing  :D
Here's  another low profile 3/8" chain......the Oregon 76LG. Introduced in 1976 and discontined about 20 years later.
An actual true 3/8 pitch chassis to match a full size 3/8 sprocket.
Cutter bits are equivalent  in size to a .325 and chisel to boot.

Top picture....76LG
Middle picture ...old timbersport race chain trick. Full size cutter on lightweight  76LG chassis.
Bottom picture.....Stihl 33Topic Super 3/8" low profile chain compared to full size Stihl 33Rapid Super 3/8"chain.

 

 (http://www.forestryforum.com/gallery/albums/userpics/21589/20140326_165204.jpg) 

 (http://www.forestryforum.com/gallery/albums/userpics/21589/20131226_202107_LLS.jpg) 

 (http://www.forestryforum.com/gallery/albums/userpics/21589/20140327_103913.jpg)
Title: Re: If 3/8 takes more power
Post by: kellysguy on May 29, 2015, 09:21:54 PM
 smiley_dizzy
Title: Re: If 3/8 takes more power
Post by: pabst79 on May 30, 2015, 11:18:25 PM
smiley_dizzy

X2   say_what
Title: Re: If 3/8 takes more power
Post by: SawTroll on May 31, 2015, 08:56:34 AM
Drive sprocket size is a major factor here, but the end result also depends on exactly which chain models are involved


I understand that completely, with all things being equal are the 3/8LP the easiest to pull? (excluding 1/4 of course).
I believe at least most 3/8" lo-pro chain "pulls" easier than 1/4" chain, as there are way fewer cutters?

However, I am not an expert on 3/8" lo'pro, as I haven't used it for 15 years or so, and I never used 1/4".....
Title: Re: If 3/8 takes more power
Post by: Cut4fun on May 31, 2015, 09:16:00 AM
Now I'll  make things really confusing  :D
Here's  another low profile 3/8" chain......the Oregon 76LG. Introduced in 1976 and discontined about 20 years later.
An actual true 3/8 pitch chassis to match a full size 3/8 sprocket.
Cutter bits are equivalent  in size to a .325 and chisel to boot.

Top picture....76LG
Middle picture ...old timbersport race chain trick. Full size cutter on lightweight  76LG chassis.
Bottom picture.....Stihl 33Topic Super 3/8" low profile chain compared to full size Stihl 33Rapid Super 3/8"chain.

 

I understood 100% of all of that.  ;) ;D
Title: Re: If 3/8 takes more power
Post by: Philbert on May 31, 2015, 10:32:26 AM
I understood 100% of all of that.
Yeah. Some companies used to make full sized 3/8 pitch chain with smaller cutters. 

Philbert
Title: Re: If 3/8 takes more power
Post by: HolmenTree on May 31, 2015, 02:08:48 PM
Thanks to  Kevin (Cut4fun) a few years ago I was able to buy about 9 loops of the 76LG and 33TS chain from him that he found.
I haven't  been able to find this chain for about 20 years  prior. :)
Title: Re: If 3/8 takes more power
Post by: SawTroll on May 31, 2015, 03:16:05 PM
Now I'll  make things really confusing  :D
Here's  another low profile 3/8" chain......the Oregon 76LG. Introduced in 1976 and discontined about 20 years later.
An actual true 3/8 pitch chassis to match a full size 3/8 sprocket.
Cutter bits are equivalent  in size to a .325 and chisel to boot.

Top picture....76LG
Middle picture ...old timbersport race chain trick. Full size cutter on lightweight  76LG chassis.
Bottom picture.....Stihl 33Topic Super 3/8" low profile chain compared to full size Stihl 33Rapid Super 3/8"chain.

 

 (http://www.forestryforum.com/gallery/albums/userpics/21589/20140326_165204.jpg) 

 (http://www.forestryforum.com/gallery/albums/userpics/21589/20131226_202107_LLS.jpg) 

 (http://www.forestryforum.com/gallery/albums/userpics/21589/20140327_103913.jpg)
Basically true, but there are no such thing as true 3/8" chain, as the pitch basically are .366 on both regular and lo-pro, and not .375.  ;)
Title: Re: If 3/8 takes more power
Post by: HolmenTree on May 31, 2015, 09:40:12 PM
Basically true, but there are no such thing as true 3/8" chain, as the pitch basically are .366 on both regular and lo-pro, and not .375.  ;)
You know what I mean Niko :D
I was just saying the 3/8 low profile 76LG and 33TS are true 3/8 chassis to fit a standard sprocket where the 91 series or Picco 3/8 LoPro chain are not a correct fit.
The guide bar companies who have spent millions of dollars in research and development for the last 60 years or so still call the 3/8" pitch .375 as the numbers on my bar tip shows..............
 

 (http://www.forestryforum.com/gallery/albums/userpics/21589/20140326_165204.jpg)