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beginner question from an older user

Discussion in 'Chainsaw' started by AmateurSawer, Feb 14, 2020.

  1. AmateurSawer

    AmateurSawer ArboristSite Operative

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    Would changing an 18" bar to a 16" on a 45cc saw make any difference in the power if you are cutting 12" to 14" diameter or less ?
    Seems like it wouldn't.
    .325 pitch and .063 groove on both.
     
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  2. ammoaddict

    ammoaddict Addicted to ArboristSite

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    Some say it does, but I agree with you. I can't see how 2" of bar can make any noticable difference in power.

    Sent from my moto g(7) power using Tapatalk
     
  3. DaddyFlip

    DaddyFlip ArboristSite Member

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    It's a 10% increase in RPM, everything else equal, just because you're running shorter chain/fewer links. Higher RPM plus sharp chain helps a small saw do more work with less.
     
  4. rupedoggy

    rupedoggy Addicted to ArboristSite

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    How does shortening the bar increase the RPM 10%? Answer: it doesn't
     
  5. SEAM

    SEAM Addicted to ArboristSite

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    Shouldn't make much difference power-wise but will definitely improve balance and handling.
     
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  6. hardhat

    hardhat ArboristSite Operative

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    Would improve slightly due to less friction on bar due to shorter length of chain rubbing against bar. Would accelerate faster due to less rotating mass. I don't think either of these would be enough to notice while cutting or probably while just revving it out of the wood for that matter :).

    Now switching to 3/8 lo pro (narrower kerf than 0.325) would almost certainly cut faster :)
     
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  7. DaddyFlip

    DaddyFlip ArboristSite Member

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    It does increase the RPM of the chain, everything else equal, for the same RPM of the saw; the chain is shorter... It has to.
     
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  8. rwoods

    rwoods Addicted to ArboristSite

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    A shorter chain turning its length faster than a longer chain turning its length does not equal a faster cutting speed - the cutters on each are moving the same speed except for any increase in the engine speed due to less friction. Ron
     
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  9. 2stroker

    2stroker ArboristSite Operative

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    The chain speed (feet/second) is a function sprocket/rim diameter and rpm. Bar length is irrelevant.
    A slight increase in friction from a longer bar would be a minor factor.
    2stroker
     
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  10. Philbert

    Philbert Chainsaw Enthusiast

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    If considering a different bar / chain combo, consider a 16" narrow kerf bar and chain (e.g. Oregon type 95), especially with that size saw.

    A 45cc saw should have a 14" to 16" bar in my opinion. The NK chain takes a smaller 'bite', so it takes less power to pull it through the wood. It makes your powerhead feel like a more powerful saw. Plus, it would be pulling a much lighter chain than what you have now.

    Philbert
     
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  11. Huskvarna hotellgäst

    Huskvarna hotellgäst ArboristSite Guru

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    It does increase the RPM of the chain loop but not the speed of the chain in the cut.
     
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  12. DaddyFlip

    DaddyFlip ArboristSite Member

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    You are right. The linear speed is the same. But doggone it, going from 18 to 16 on my 42cc made a marked perceived improvement. Probably due to new BnC and better handling. Oiled like a champ also.
     
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  13. Jkstihl

    Jkstihl Chainsaws make me fap.

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    Just put a 32" .404 on it and be done.
     
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  14. LonestarStihl

    LonestarStihl Addicted to ArboristSite

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    I have to agree it does I crease RPM of the chain. I think some are getting it mixed up with rpm of the engine as of tached or chain speed which isn’t what you’re saying.

    To simplify it like taking 2 runners at the same speed. Now put one on the inside lane and one on the outside lane of the track. The one on the inside lane(shorter bar) is going to run more laps(revolutions) than the runner on the outside lane(longer bar) in the same minute of running.
     
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  15. DaddyFlip

    DaddyFlip ArboristSite Member

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    Yes, runner analogy is good. Guy on the inside track will win the race at equal speed but apparently guy with the shorter bar won't win the cut.
     
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  16. LonestarStihl

    LonestarStihl Addicted to ArboristSite

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    Nope, having teeth along the whole chain helps no matter what. Just saying that the RPM of the chain is a true statement but it won’t necessarily help anywhere else. The engine still pulls at the same speed and it doesn’t matter which cutter is digging in(wether it’s the same one over and over again or another one a few less times). If anything, along those lines, a longer bar should actually dull slower because they’re sharing the work more...therefore you could get a slight increase in amount of time you can cut with the chain.... dun dun dunnnnnn
     
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  17. Duce

    Duce Addicted to ArboristSite

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    But, Cutters on chain are like cars on track. Still traveling the same speed, one car will just make contact wood more times on shorter lane.
     
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  18. LonestarStihl

    LonestarStihl Addicted to ArboristSite

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    I also said it wouldn’t cut faster or anything else. Look above your comment. Just backing up what the other gentleman said because. Would indeed increase chain RPM, without a doubt. But no actual cutting speed or anything else...which is what OP wants. But he did make a true statement.
     
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  19. Duce

    Duce Addicted to ArboristSite

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    You are correct, did not read that. Must be very slow at typing, will stay on the porch. :cheers:
     
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  20. LonestarStihl

    LonestarStihl Addicted to ArboristSite

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    Can I come sit on the porch and drink some coffee with you? Lol :drinkingcoffee:
     
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