The function of pitch

[rowan lee]

Sorry for consistently asking stupid questions in this section - but why are there different pitch sizes? As far as i'm concerned as an occasional chainsaw user, the only function of pitch for me is indicating the file size i should use to sharpen the cutters.

 

Surely one universal pitch size could cater for all types of chains, irrespective of cutter size?

 

Please enlighten me folks

[Steve Bullman]

im guessing its strength. i doubt the smaller pitches would hold out too well being powered through big timber on an 880

[3dogs]

Its to do with gearing the saw. The nose sprocket and the drive sprocket make a gear ratio linked by the chain so therefor require the correct pitch of chain appropriate to the size/power of the saw. Hence changing the chain pitch on a saw will re-gear it. Hope that makes sense:thumbup1:

[Bolt]

hmmmmmmmm.

 

But, little tiny ms200s use 3/8", and so do mighty ms660s (although the gauge is different)

 

So why bother with .325" (which is a silly pitch).

 

It can only be down to tradition.

[rowan lee]

Thanks all, food for thought

[Mesterh]

The pitch doesn't dictate the file size, the size and type of cutter does. Re see Bolts post.

 

Interesting question though and would like to hear what the right answer is.

[3dogs]

hmmmmmmmm.

 

But, little tiny ms200s use 3/8", and so do mighty ms660s (although the gauge is different)

 

So why bother with .325" (which is a silly pitch).

 

It can only be down to tradition.

 

its also scaled down to suit, same pitch diferent size. A 3/8 chain on say a 346 or ms260 would cause the engines to struggle whereas a 3/8 picco/pixcel would not be upto the job expected of it so .325 pitch gives us a happy medium:thumbup1: Weve not mentioned 1/4" or 404" pitch yet.

[Bolt]

its also scaled down to suit, same pitch diferent size. A 3/8 chain on say a 346 or ms260 would cause the engines to struggle whereas a 3/8 picco/pixcel would not be upto the job expected of it so .325 pitch gives us a happy medium:thumbup1: Weve not mentioned 1/4" or 404" pitch yet.

 

Yes, But..

 

A .325" pitch chain has, per metre of chain moved, more cutters cutting than a 3/8" because the .325 is closer together, so for an identical profile, the 3/8" chain would be less work for the engine.

[ben lightfoot]

my belief is that its to do with the clearing space from the back of the cutter to the next depth gauge so the 1/4 3/8 found on top handle saws and smaller hobby saws has a relatively large clearing area due to the small power out put similar to .404 on large saws these saws dont rev massivley just plod along and with long bars need a large clearing area or they would just get blocked up, hope that helps but i hope im right too lol

[3dogs]

Yes, But..

 

A .325" pitch chain has, per metre of chain moved, more cutters cutting than a 3/8" because the .325 is closer together, so for an identical profile, the 3/8" chain would be less work for the engine.

 

But the gear ratio would not support this, unless you were purely working on soft woods were the tolerances are greater.

 

I used to run husky 254 on 3/8 pitch but i was working in Corsican / lodge-pole mix however try the same set up on a beech or ash or similar, even a knotty pine could cause problems. Simply buying a 262 would have been a better option.