Questions about pitch and gauge

[Chainsaw Pete]

Why do we have two different pitch chains that are so close - .325 and 3/8? Both pitches are available in three common gauges. Is the duplication due to one manufacturer deciding on one pitch and another on the second pitch? Are there any significant differences in performance between the two pitches?

I guess the .404 pitch, which only comes in a .063 ga is meant for larger, more powerful saws although the pitches noted above are also available in this larger pitch. Somewhere I read that mechanized saws use the .404 which suggests strength is part of the reason for this size.

I'd also surmise that the .043 - low profile 3/8 chain is for small low powered saws like my pole pruner, and I consider this a specialty chain.

 

[sean donato]

Tons of variables between pitch size. Narrow curf, low profile etc. Different cutters/ profiles, differences in depth gauges, safty bumpers etc. The gauge is up to the user, generally speaking .050, .058, a.d .063/4 are rhe normal ones. Some odd balls with the .043, but you can get the same chain in .050. I wouldn't say it's a specialty item, or for low power saws per say. The .043 allows a narrower curf, which allows for less parasitic loss = faster cutting. It's more or less a stihl thing, but others have adopted it.
Gauge is Just personal preference really. I usually try to stick with .050 up to 24" then .063 for .325 and 3/8. Only have one saw running .404 .063 is about the only gauge you can get anymore.
.404 can be had .063 then .080 (harvester chain) then there's still 3/4 chain for harvester use, .122. Some old saws ran 1/2 pitch or 3/4 pitch, pretty much obsolete for hand held saws these days.

 

[Chainsaw Pete]

Tthen there's still 3/4 chain for harvester use, .122.

What is harvester use?
I'm running 3/8, .050 on my two saws, but for some reason I have 3 loops and a Woodland Pro bar in .325 for my MS250. Dinged if I know now why I bought that bar and chains. I try to standardize my tools having another gauge for the same standard Oregon chains that I use makes no sense to me (well, it does now, maybe it did not when I bought them).

 

[Mad Professor]

What is harvester use?
I'm running 3/8, .050 on my two saws, but for some reason I have 3 loops and a Woodland Pro bar in .325 for my MS250. Dinged if I know now why I bought that bar and chains. I try to standardize my tools having another gauge for the same standard Oregon chains that I use makes no sense to me (well, it does now, maybe it did not when I bought them).

Big machine that grabs a whole tree by the trunk and cuts it off at the base



The MS250 has the smaller mount bars. Most 3/8 chain bars are 3003 mount.

 

[sean donato]

What is harvester use?
I'm running 3/8, .050 on my two saws, but for some reason I have 3 loops and a Woodland Pro bar in .325 for my MS250. Dinged if I know now why I bought that bar and chains. I try to standardize my tools having another gauge for the same standard Oregon chains that I use makes no sense to me (well, it does now, maybe it did not when I bought them).

Harvester = mechanized industrial cutting.
I had that "standardize" thought for a hot second. Doesn't work in practice. I have saws from 30cc to 100+ cc. Different brands, different mounts. Doesn't make any sense to try and standardize all of them on one chain type. .325 and 3/8 belong on different saws for various reasons, and I'm not running std 3/8 on a 50cc or smaller powerhead, have a few 60cc class saws that still run .325 that have small mount bars. Beyond that it's all 3/8 or .404 for the larger saws. I'd never run std 3/8 on a ms250, spire leaving a lot of performance on the table with a full size cutter and wide kerf chain.

 

[BeatCJ]

Why do we have two different pitch chains that are so close - .325 and 3/8? Both pitches are available in three common gauges. Is the duplication due to one manufacturer deciding on one pitch and another on the second pitch? Are there any significant differences in performance between the two pitches?

I guess the .404 pitch, which only comes in a .063 ga is meant for larger, more powerful saws although the pitches noted above are also available in this larger pitch. Somewhere I read that mechanized saws use the .404 which suggests strength is part of the reason for this size.

I would guess it was a random chain development thing. Now it's a typical use perpetuated by manufacturers.

I suspect that with a smaller saw, 3/8 would be too grabby for acceptable performance. I just watched a performance video on Youtube for Ego battery saws. With the saw they were running, the 3/8 performed significantly faster. I did notice that had more issues with it bogging when they tried to push it. The video stated the saw they were testing was equivalent to a 50cc saw. My only saw with .325 is my 42cc 024. It is my belief that's about the switch over point.

 

[Del_]

Look into Stihl Pro chain .050, .325. Supposed to be a faster cutting chain and makes a narrower kerf.

I run 3/8 Stihl Picco Super on my 241C. I'm square filing it as it comes round ground.

 

[Franny K]

Are there any significant differences in performance between the two pitches?

Full sized 3/8 is sized for up to 100cc saws. tie strap thickness and height. bearing or bushing diameter, size of drive links, it is more than a decimal distance.
Normal .325 is for up to 62cc, .325 NK is for up to 55cc and the mini .325 probably up to something in the 40cc area.
.325 and down use the smaller spinner anvil.
The .043 stuff will likely call for the smaller breaker punch.

 

[heimannm]

.404 chain is not restricted to .063 gauge, still plenty of .058 available and from time to time you can find some old supplies of .404 in .050 as well as .080 gauge harvester chain.

3/8 LP is yet another variation, with the smaller chassis and cutters it also works well on underpowered saws. More of a homeowner/occasional used type chain. 3/8 LP started out as .050 gauge but in an effort to make under powered saws with long bars functional, .043 "narrow kerf" chain was introduced, reducing the amount of wood the saw has to remove making a cut. While the actual pitch (distance between rivets) of 3/8 LP and "full" 3/8 are the same, they require different sprockets due to the difference in chassis height.

The LP (Pico) sprocket is actually slightly larger in diameter due to the smaller chassis.



At one time Pioneer and Saber both made a .315 pitch (normally .050 gauge) and McCulloch sold thousands of saws with their own .354 pitch (both .050 and .058 gauge).

Older saws (the early days) had 1/2" pitch, 9/16" pitch, 5/8" pitch, 3/4" pitch, and even 7/8" pitch. The 3/4 and 7/8 pitch chain was often .080 or .122 gauge.

Some manufacturers like Draper Blue Jet made bars and chain in .070 or .074 gauge.

McCulloch manufactured some specialty chain for the BP-1 saws in 1/2" pitch with smaller drivers and .074 gauge (AR, AC, AR8).

There are still saws today running 1/4" pitch .050 gauge, and Stihl makes a narrow kerf 1/4 pitch (Pico) in .043 gauge.



The you have the options of cutter sequence...

Full house with a cutter for every driver

Full compliment with a cutter every other driver

Full skip with three drivers between cutters

Semi skip combining full compliment and full skip

Some vendors even offer super skip with 6 drivers between cutters for milling operations.



I have about 125 different chain options on this display, and that hasn't even really scratched the surface.



Then you have the various cutter types; chipper, semi-chisel, chisel, square ground chisel, carbide tipped in a dozen or more flavors, guard links, bumper links, low vibration, safety chains...

So many choices...



Mark