gmax
Addicted to ArboristSite
Gday Chris, Yes A few of us have them, unfortunately their pretty scarce these days in OZ.
Older saws.....why gear drive???
- Thread starter Dan_IN_MN
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Gday Chris, Yes A few of us have them, unfortunately their pretty scarce these days in OZ.
sawmandave
ArboristSite Operative
the old days of logging
gear drives were loved to be used on the deck of a logging job because the wood was always dirty and the slow chain speed coupled with large chain pitch usualy kept the chain sharp...bow saws and gear drives were a great marrige. pulp wood and fire wood cutters loved them
gear drives were loved to be used on the deck of a logging job because the wood was always dirty and the slow chain speed coupled with large chain pitch usualy kept the chain sharp...bow saws and gear drives were a great marrige. pulp wood and fire wood cutters loved them
DEG305
ArboristSite Operative
Way back when, I traded the original Mac 33B that we had on the farm, for a Homlite gear drive/direct drive "Stick shift, HEAVY is all I remember it to be! Now I'm wishing I had it back.
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sawmandave
ArboristSite Operative
cutting down trees the older loggers used different metods than used today with newer direct drives
sawmandave
ArboristSite Operative
gear drive saws need to respected
sawmandave
ArboristSite Operative
I have a nice homelite superwiz-66 .. i am installing a 3 ft bar with 404 pitch full skip super chisel chain.. ifound 1 404 sprocket for one of those saws .. which i think is hard to find:
RandyMac
Stiff Member
What differences?
All chainsaws do, the little saws are the most dangerous. The main thing with gear-drives is that they will walk out of a binding cut with surprising speed. Most direct-drives will stall when bound.
Full skip will reduce efficiency, not the best choice.
Thats blazeing fast compared to a misery wip! I sure that Ol' timers thought that they were a marvel (I do) and once they got used to the increased speed and ease of use they embraced the new power saw and their growing mid section. I'm sure there was some fellas that didn't think that way though. Loud, heavier, you have to start it, more dangerous, extra jug for fuel, ect.
Dan_IN_MN
Addicted to ArboristSite
WoW!
I never thought that my thread would live this long! This thread has really become a good read!
I never thought that my thread would live this long! This thread has really become a good read!
paccity
Addicted to ArboristSite
yup though's geardrives are cool. have a few that i need to get bitting some wood again.View attachment 213810View attachment 213812View attachment 213813View attachment 213814View attachment 213815
paccity
Addicted to ArboristSite
randymac, show a pic of that monster yellow geardrive you have.:msp_wink:
paccity
Addicted to ArboristSite
and don't forget to get in on the 137cc geardrive saw raffel for stump.
RandyMac
Stiff Member
Here we go paccity.
Rose bushes tremble in terror when a Cox Beaver is mentioned.
At 1.4 cubic inches, with a 3.5 to 1 gearbox, it will knock the fluff off any size dandylion.
I used this 660 for years back in my heathen days.
Rose bushes tremble in terror when a Cox Beaver is mentioned.
At 1.4 cubic inches, with a 3.5 to 1 gearbox, it will knock the fluff off any size dandylion.
I used this 660 for years back in my heathen days.
Here's a few of my geardrives.
Lee
Homelite 990G
Mac 797G
Mac 101G Video
Stil 090G
Stihl 090G
Two Homelite Super 1130
Restored Homelite 3100
Lee
Homelite 990G
Mac 797G
Mac 101G Video
Stil 090G
Stihl 090G
Two Homelite Super 1130
Restored Homelite 3100
RandyMac
Stiff Member
Where are those 900 series Lee buddy?
Here ya go Randy, Is this what your talkin bout.
I have a few more since these pic's were taken.
They're Is a 9-26, 900G, 2 909G's, and a 990G
Lee
I have a few more since these pic's were taken.
They're Is a 9-26, 900G, 2 909G's, and a 990G
Lee
RandyMac
Stiff Member
that be them Lee
thanks
thanks
While the basic concept was answered pretty well in the second post, http://www.arboristsite.com/chainsaw/123923.htm#post2000406
...no one seems to have explained why they used gear drive. Modern saws are quite effective with chains that travel at high speed. They get this effectiveness by using very high revolution speed. So a 5 hp motor at 12,000 rpm can take MANY tiny bites of wood and cut very effectively.
Switch to an old fashioned saw at 5hp. The engine RPM is only about 4k, so your chain is going to turn pretty slowly. This means that chips will not clear the groove as well as modern saws, it means that even a slightly dull saw will not pull easily through the wood, and it means that you must FORCE the chain through the wood.
Much like it takes tons of raw force to push a nail into a 4x4, a one pound hammer can do the job pretty well with fast light blows. The physics are not much different for saw chain in wood: slow it down and the force required goes up exponentially. This additional force requires a big heavy chain to survive, and mandates larger contact surface at the sprocket to deliver the torque required.
So the engineers went to work: they could put somewhat bigger diameter sprockets on the big chain drive to capture the bigger forces applied by the wood against the chain; but this reduced the ability of the engine to pull the load. A bigger diameter sprocket means reduced torque delivered to the chain.
How to correct this problem? Gear reduction ! This drives the chain with MUCH more force and relieves the clutch from having to deliver all that torque, too.
Since the chain is being forced through the wood, rather than slicing through quickly, you will also see that the older chains were all "chipper" tooth, rather than semi-chipper or square toothed, like we see today. I won't even go into the older styles of cutters that have fallen by the wayside.
Obviously, all that "bigger, heavier, stronger" stuff makes for a damned heavy saw, so the manufacturers have been working on "lighter and faster" for at least 40 years.
...no one seems to have explained why they used gear drive. Modern saws are quite effective with chains that travel at high speed. They get this effectiveness by using very high revolution speed. So a 5 hp motor at 12,000 rpm can take MANY tiny bites of wood and cut very effectively.
Switch to an old fashioned saw at 5hp. The engine RPM is only about 4k, so your chain is going to turn pretty slowly. This means that chips will not clear the groove as well as modern saws, it means that even a slightly dull saw will not pull easily through the wood, and it means that you must FORCE the chain through the wood.
Much like it takes tons of raw force to push a nail into a 4x4, a one pound hammer can do the job pretty well with fast light blows. The physics are not much different for saw chain in wood: slow it down and the force required goes up exponentially. This additional force requires a big heavy chain to survive, and mandates larger contact surface at the sprocket to deliver the torque required.
So the engineers went to work: they could put somewhat bigger diameter sprockets on the big chain drive to capture the bigger forces applied by the wood against the chain; but this reduced the ability of the engine to pull the load. A bigger diameter sprocket means reduced torque delivered to the chain.
How to correct this problem? Gear reduction ! This drives the chain with MUCH more force and relieves the clutch from having to deliver all that torque, too.
Since the chain is being forced through the wood, rather than slicing through quickly, you will also see that the older chains were all "chipper" tooth, rather than semi-chipper or square toothed, like we see today. I won't even go into the older styles of cutters that have fallen by the wayside.
Obviously, all that "bigger, heavier, stronger" stuff makes for a damned heavy saw, so the manufacturers have been working on "lighter and faster" for at least 40 years.
