What's the deal with pitch?

wavefreak · Apr 29, 2009

This has probably been asked a thousand times but I didn't see a place to get the info. What do all the variables in chain actually DO? Pitch basically changes the amount of links per foot, gauge the strength and kerf, then there is chisel and semi-chisel, skip chain, low profile etc etc.

Is there a FAQ that explains not just what these are but why you might choose different configurations?

BobL · Apr 29, 2009

wavefreak said:
This has probably been asked a thousand times but I didn't see a place to get the info. What do all the variables in chain actually DO? Pitch basically changes the amount of links per foot, gauge the strength and kerf, then there is chisel and semi-chisel, skip chain, low profile etc etc.

Is there a FAQ that explains not just what these are but why you might choose different configurations?

I don't believe it's more complicated than bigger pitch chains are for bigger & longer bars and big powerheads and VV.

LAndrews · Apr 30, 2009

Here's one tip about pitch - wish I had a pic to show this...can't get a decent image with my crappy camera.

The bigger pitch chains have the advantage of having a lot more material that can be removed before the chain can't be sharpened any more. So, a .404 chain has 29 mils (.75mm) more top plate length (probably 2-5 sharpenings) than a .375 chain. The .325 links look positively anemic compared to the .404 - from a glance it seems like they'll only get about 1/2 as many sharpenings. Seems like this would be more significant if one was working 30degree cutters down for milling.

OTOH, since chains stretch and wear with use, it may not be good to use the same chain over and over. Stretched chains tend to wear sprockets and while rims are cheap, I don't know too many folks that change rims along with chains to ensure even wear. I've never worked a chain all the way down to the nub before I decided that it was too floppy to keep using. (am a bit afraid of a broken chain, dono why)

Somewhere in there is a compromise that works for a lot of people.

BobL · Apr 30, 2009

LAndrews said:
The bigger pitch chains have the advantage of having a lot more material that can be removed before the chain can't be sharpened any more. So, a .404 chain has 29 mils (.75mm) more top plate length (probably 2-5 sharpenings) than a .375 chain. The .325 links look positively anemic compared to the .404 - from a glance it seems like they'll only get about 1/2 as many sharpenings. Seems like this would be more significant if one was working 30degree cutters down for milling.

This may well be the case, but the 404 chains also have a wider kerf so you will use far more gas in cutting that extra kerf than any $ saving in chain life. If you use the same size saw the smaller chain also reduces wear and tear on your saw as well.

OTOH, since chains stretch and wear with use, it may not be good to use the same chain over and over. Stretched chains tend to wear sprockets and while rims are cheap, I don't know too many folks that change rims along with chains to ensure even wear. I've never worked a chain all the way down to the nub before I decided that it was too floppy to keep using. (am a bit afraid of a broken chain, dono why)

. A chain that is treated properly and kept sharp should not stretch much after its initial run in period. If it does, this is a signal to me that there is something wrong and that chain is immediately retired. While broken chains are no picnic I an not too worried about them. My experience is that a chain near the end of its life loses a cutter rather than breaks.

Somewhere in there is a compromise that works for a lot of people.

Yep - I agree with that

wavefreak · Apr 30, 2009

Pitch and gauge isn't really that hard for my brain. Bigger chain for bigger jobs and saws. You basically fit the chain to maximize material removal without bogging down the saw. I'm betting a lot of experience is involved.

There seems to be even more variation in the shape of the teeth and the angles at which they get sharpened. I'm inclined to not worry about it too much for regular work around and buy stock chain, but I'm pretty sure I will end up grinding my own ripping chain (I have access to a good sharpening setup). There's some good threads here on how to grind a ripping chain, but I'm one of those obsessive types that likes to know why as well.

I'm also seeing exhaust mods on the forum here. What's up with those? More power? Makes me think nitrous oxide could be fun.

synness4 · Apr 30, 2009

it's easier to look at it like the old loggers 9/16 ,1/2 ,7/16 were standard on there big saws with long bars,the massive amount of torque would pop a 3/8 chain !!!! use smaller when you can.

BobL · Apr 30, 2009

synness4 said:
it's easier to look at it like the old loggers 9/16 ,1/2 ,7/16 were standard on there big saws with long bars,the massive amount of torque would pop a 3/8 chain !!!!

I wouldn't bet on that. The reason they were so big was because some of those old chains were soft as butter and more stretch on them than a pair of grannies bloomers

What's the deal with pitch?

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