How to figure chain rpm's?

[Husky nut]

I'm taking an uneducated guess so you tell me if
i'm correct...
Basing this off a 72 dl chain, a 7 tooth rim and 12500 engine rpm's

72/7=10.286 (rim turns to make a full chain revolution) then 12500/10.286=1215.244 chain revolutions per minute...Is this correct?


Just an idiot trying to do math...

 

[scottr]

?

Yes

 

[1953greg]

to take that a little farther,

that 72 dl (assuming a 3/8 chain) is bout 4.4' long. 1215rpm x 4.4' = 5346 ft/min or 89 ft/sec (88fps = 60mph) or 60 miles per hour!!!!!!!
scootin' aint it??!!!

good day 1953greg

 

[Marco]

Anybody see that Sienfeld episode where George got smart?

 

[Husky nut]

to take that a little farther,

that 72 dl (assuming a 3/8 chain) is bout 4.4' long. 1215rpm x 4.4' = 5346 ft/min or 89 ft/sec (88fps = 60mph) or 60 miles per hour!!!!!!!
scootin' aint it??!!!

good day 1953greg

Good work...but its just alil shy of 60 mph try 59.8 mph 72,921.73 revolutions per hr and a 8 tooth would jump it up to 68.34 mph totaling a whooping 83,333.33 revolutions per hour

 

[Husky nut]

thats assumming your 4.4' is actually 4' 4"'s which is 4.333....but i'll have to measure a 20" 72dl chain at work to get a correct number on here

 

[Grande Dog]

72 drive links of 3/8 is 4.40".

Grande Dog
Master Mechanic
Discount Arborist Equipment and Tree Care Supplies

 

[Crofter]

Just being difficult here greg, is that using 3/8 nominal or the actual which is around .367 Lol!

 

[Fish]

Well if you were using my patented bar/chain system, then Einstienien
physics would have to be used, as my chains achieve speeds that start to
change what we take for granted. I have a hard time finding anyone to use
my saws in competition, as they age rapidly, and my company's health insurance provider has gone belly up . If you need detailed details, I will have to defer to our corporate engineers, Glens and Simon, as we mortals are too stupid to comprehend what they have to say.

 

[16gauge]

Just being difficult here greg, is that using 3/8 nominal or the actual which is around .367 Lol!

Have the chain makers also taken liberty with mathematics? 3/8 = 375/1000 = .375 at least when I went to school...what do you mean by 'nominal'?

 

[Grande Dog]

I gleened that from the Oregon application guide. Their system calls for 1640 drive links per 100' roll whether it's standard 3/8 or Low Profile. Going by that, its 4.39 feet in 72 drive links.

Grande Dog
Master Mechanic
Discount Arborist Equipment and Tree Care Supplies

 

[Simonizer]

Well if you were using my patented bar/chain system, then Einstienien
physics would have to be used, as my chains achieve speeds that start to
change what we take for granted. I have a hard time finding anyone to use
my saws in competition, as they age rapidly, and my company's health insurance provider has gone belly up . If you need detailed details, I will have to defer to our corporate engineers, Glens and Simon, as we mortals are too stupid to comprehend what they have to say.

*kisses Fish on the forehead*
(not in a gay way).,

Worry-not, my short-peckered friend. I am a self-proclaimed, infinite source of knowledge. Cheers.

 

[Crofter]

16guage; appropriate methods have been posted here to answer the original posters question of calculating rpm of a chain and I think we have gotten off into quibbling. What I took a slight dig at is that there is a bit of a terminology problen in manufacturers designation of chain sizes.

There is 3/8 Lo Profile, 370 low profile, 365 low profile an other titles for low profile chain.

There is what is sometimes called standard 3/8, .375 and perhaps other names.

in some cases components from the two lines can be mixed and matched and sometimes not, so they try to come up with unique descriptions to keep people from trying to do so. One of our former members, Glens measured a number of chains and the actual effective pitch of them are all approximately .367 of an inch and non are actually either 3/8 or .375 of an inch. You can see how much it really matters!

 

[bugfart]

"Worry-not, my short-peckered friend."

Don't let him kiss you Fish. Simon gets all confused when measuring things that are longer than they are wide.

 

[Fish]

I use millimeters when I measure, it sounds better.

 

[1953greg]

"Just being difficult here greg, is that using 3/8 nominal or the actual which is around .367 Lol!"

hey crofter, i give up!

grande dog, thanks. a newbie needs all the help they can get

stihl dm fast anyway one figures it.

good day 1953greg