Which is the best size drive - .050,.058 or .063 and why?

[njforestfire]

I am curious to hear about the pros and cons of the different drive sizes. I have always run .050 size 3/8 RC chain but would like to know if or what I might add in performance if I bump up to a larger size (.058). I understand that the chain would be a tad bit heavier but also slightly stronger.

Just out of curiosity, what is run on hotsaws?

Thanks for the replys.

 

[sedanman]

A lot of the .050 chain is 'coined' or flattened down to .050 from thicker drivers. Take a close look at your .050 chain there is a step in the thickness of the drive links. No benefit to either set-up imho.

 

[P_woozel]

I like the .063 on my bigger saws cause I think it takes a little better beating, from a wedge smashing it, getting caught in the cut, ckearing the cut when the tip is buried, etc. :umpkin:

 

[njforestfire]

Woozel, what size are your 'bigger' saws?

 

[SawTroll]

A lot of the .050 chain is 'coined' or flattened down to .050 from thicker drivers. Take a close look at your .050 chain there is a step in the thickness of the drive links. No benefit to either set-up imho.

As far as I have concluded, after going through the archives and asking questions, I think Sedanman is basically right. I don't know if this applies to all makes of chain though.
The 0.063 chain is usually (if not always) made on a heavier/sturdier chassis, and cuts a slightly wider Cerf. This should result in slower cutting - but I don't know if you would notice it at all?

 

[tony marks]

my saw was an 028 for yrs..now they all run .50 .. cant see any difference..
i have thot about trying .63 on modified saws tho..

 

[TonyM]

One advantage to using .050 gage is that as the bar rails wear, you may get to a point that you can use .058 gage and get a little more life out of the bar.

 

[SawTroll]

One advantage to using .050 gage is that as the bar rails wear, you may get to a point that you can use .058 gage and get a little more life out of the bar.

A saw dealer (Husky) told me the same thing once.
As it is , I had a Chance to test the theory when my father in law gave me his old Jonsereds Raket 621. The .058 bar was so worn that a .063 chain fitted. Only trouble was that the wear had a slight V-shape, enough to make the combination close to useless for horizontal cuts....... .....bought a new bar pretty fast!

 

[P_woozel]

Woozel, what size are your 'bigger' saws?

70cc and up.

 

[Pioneer]

It seems to me one advantage to a larger guage might be reduced drive tooth wear because of the larger contact point. Something to consider in a big saw with lots of power.

 

[Molecule]

some numbers ...

re the bar ... 050 v 065 compared

a 20" x .050 x 72-drivelink laminated sprocket nose is .170" thick and weighs about 40 oz.

add .015 thickness to the interior spacer to make it an 065 bar, and it should now be .185 thick (an increase of 8.8%) and increase in weight by 3.5 ounces (.22 lbs).

however, the bar's structural strength to resist bowing, if a long one, or for bad habbits like flipping logs and etc., should increase by 18%.

so mainly the bar gets a lot stronger.

re the chain ...

estimate that the 1/3 of the total weight of a 72-dl chain (at roughly 11 oz) is in the drivers, and 2/3's is in tie straps and cutters. if the drive links increase in width by 30% (050 to 065), the total chain increases in weight by say 10%, or say 1 ounce. Not insignificant, but once accelerated, not enough to bother a 4 hp saw either. but look at the increase in potential life of the chain, by looking at the increased width in the rivit bearing surfaces inside the drive link rivit holes. For example, when held out sideways - horizontally, them old 050 chains will have lots of "hang" in them. the 065 chains will stay straighter.

for example, Stihl recommends 065 gauge for their .325 chains in their 260s for example ...

Dolmar recommends 058 gauge for their 3/8 chains for European and Canadian markets ...

the one difference not considered is that for a given chain tension, the cutters in the lighter 050 chains might have a faster harmonic rocking action in the cut than a chain with heavier drive links ...

 

[Crofter]

Valid points Molecule. for your calculations though the .050 (and .058) chains are both .058 through the drive link body and only the drive tangs below the side rail elements are reduced. The difference in weight does not go away after accelleration; that would only be the case if the chain travelled in a circular loop. The internal velocity changes of the elemnts as they travel their irregular path are an ongoing power loss that increases with their weight. Pioneer is correct in the difference in width of the drive tangs. Below is a link to a long thread on the mechanics of chain weight and its influence.

http://www.arboristsite.com/showthread.php?t=6920&highlight=difference+chain+weight

 

[Molecule]

sprocket torque - can we measure it ?

wow ... that thread belongs in the threads-hall-of-fame! the heavier chains surely would require more turning force, e.g. generate more waste heat, at the sprockets ... for the chain system alone 0.13 hp approx. This same force would "want" to equalize along the chain, but it can't due to continuous accumulation of sprocket and guide bar losses, until it returns back round to the drive sprocket, where more "torque" (work) is continuously supplied.

If I tension a chain loose and run it, it looks like it's pulling off the top bar just as much as the bottom one, which doesn't seem right as the losses at the nose sprocket should require the bottom chain to pull tighter ?? On that point, the heavier chains should "pull" out of the sprockets and "float" above the rails, while at the same time increasing tension within the chain substructure, and increasing internal loss across the drive sprocket.

Has anyone been able to (a) grapple the theoretical torque that would be required at the drive sprocket to spin a given chain, given rpm, groove and sprocket loss, bar geometry, etc ; (b) then compare that theoretical value with a *measured difference in chain tension across the drive sprocket, (b.1) out of the wood-? (b.2) in the wood-? I've always wondered how much more tension is in the chain on the pull side of the drive sprocket?

 

[Crofter]

The chain will indeed be standing above the rails at very high rpm on a hotsaw. That is why it is easy to derail by a mere sideways brush.

 

[Lawn Masters]

Now, this might just be me but my 250 seems to need less bar cleaning with .063gauge chain, while my 038's .050 chain needs cleaning almost constantly. now, like I said, this could just be me imagining things here which I think is the case.

I like either setup, they both cut wood, and dont slow me down much. I just wish I had a rim sprocket on my 250, so I could put a 9T 3/8 rim on it.