.325 faster than 3/8?

[timberwolf]

I have pushed, or rather pulled stihl .325 with an 066 on pipe, 14k plus with both 9 tooth and 10 tooth .325.

I had no problems, knock on wood. run your own chain and at your own risk.

one chain in specific also had a lot of extra metal removed.

yes it is fast, not always the fastes but none the less fast.

9T 325 L 7 spline is available as a stock stihl part.

 

[ol'homey]

Now that's what I'm talkin' about Timberwolf! The 066 uses the standard size spline and a .325 9T sprocket is readily available. I think as more folks start fooling around with .325 chain they will also realize its fast when set up right. In a few years somebody will come out with stronger(special alloy steel etc.) .325 chain that will withstand the torque from the hot saw guys. Then .325 chain will be the hot ticket and will push 3/8 out just like 3/8 pushed out 404 many years ago. Smaller, lighter chains running at faster chain speeds has been the progression so far. I see no reason for the trend not to continue.

 

[timberwolf]

Though put the 325 in larger wood or a block of maple and I have found that it chokes fast.

also with my 026 the fastest cuts I have made yet on 10 inch poplar (2.65 seconds) were with .325 8T beating 3/8 7T by 4/10 of a second. Note though the .325 chain had more work done to it.

325 is on the left in both photos, lots more gullet room on the 3/8, this adds up as the cutters are the same size and the drive lengths different.

 

[klickitatsacket]

Thanks Timberwolf.

 

[ol'homey]

Looks like it needs a smaller cutter to go with the smaller gullet, right? Maybe the Oregon,Carlton, GB etc. .325 chain has a smaller cutter and won't load up like the Stihl chain does in larger wood? What happens when you file the Stihl .325 and open up the gullet? Does it clear the chips better?

 

[timberwolf]

One other angle though minor to think about is chain weight.

a 16" 325 stihl chain weighs in at 260 grams or 9.2 oz
a 16" 3/8 weighs in at 310 grams or 11.0 oz

20% difference = if my prior energy loss calculations were correct, thats in the order of 1/10 of a hp at 12k, may be more if increased friction is taken into account. When more weight is accelerated around the bar the preasure the chain exerts on the bar goes up proportionaly with chain mass and friction increases proportionaly with that preasure betwixed bar and chain.

I have not found any use for the .325 with smaller cutters in terms of cutting speed.

opening the gullets up is assumed to help chip flow, and seem to be step one in making a stock chain cut faster step two being square filing.

 

[oldwild]

just checked all my chains, only one is .325 for the 220, all the rest are .375 or 3/8th's. The 220 will cut faster than than any of the other saws, but IMHO, it has a higher RPM, plus a smaller chain. I will put the Husky 353 against it and see what happens. Same RPM range, and the same size bars, just different chains. I don't think I want to try a .325 on the Husky though! The .375 for the Husky is a low kick-back, not as radical as the .325 for the 220, which is a full anti-kick-back. Once I start wearing chains out again, I will probably start getting some Woodsman Pro, especially for the 3 bigger saws.

 

[glens]

The 2X Stihl chain not only has less fore-aft room than the 3X Stihl chain, but there are more cutters in the wood, by a factor of 9:8.  More freed material with less room to convey it.  The other manufacturers' .325 chain has even less room yet (but they're not cutting a "full" kerf so maybe it's a wash in terms of "conveyability").

Glen

 

[Crofter]

Timberwolf; nice photography

 

[rahtreelimbs]

We need EHP to shed some light on this!!