What sprocket?

[marti384]

Hi all,
I am somewhat new to milling. I have a 3120 that I plan on milling with. My question is what size sprocket would work best? I would like to stick to a 3/8, since then some of my other bars and chains would fit the saw when stumping and bucking. Should I go 7 or 8 pin? It has a .404 on it now. Also, if I went 3/8", then what gauge would you all recommend? Currently I have a lot of .050 gauge chain. I only plan on milling stuff up to 36". I don't know if it matters, but it is an older 3120 so I don't think that it is rev limited. Thanks in advance for any suggestions.

 

[Dave Boyt]

I'm using .050 chain on a 2100, and it seems to work fine. Only 36" diameter? It will seem a lot bigger when you're actually milling it, especially if it is hardwood. I use a 7 pin sprocket for more torque. Be sure to check the threads on chains. There are some differences between ripping (sawmill) chains and regular crosscut chains.

 

[Bigdgb]

When milling with my 090 i use 7 pin, 404 semi chisel on an 48" bar,
you say you are only going to cut to 36" is this how long your bar is? (if so you will only be able to cut about 30" wide tree)

 

[marti384]

Right, that is how long the bar is. So it sounds like 7 pin is good. Do I need to be concerned with the gauge? I know some .050 chains say something like "for chainsaws 50-99cc." Is there a much higher chance of them breaking with 118cc? Thanks guys for the answers.

 

[Dave Boyt]

Use the same gauge chain as your bar. A narrow gauge chain has too much slop in a wide groove. It will cut rough, and put excessive wear on both the bar and the chain. Also make sure the bar's tip sprocket, the chain, and the saw's drive sprocket are all the same pitch. Mixing a 3/8 (.375) and a .404 will break something!

 

[marti384]

Maybe I worded that wrong. What I was asking is if I should use a .050 or a .058 with that big of a saw. I will make sure everything matches up.

 

[Bigdgb]

Maybe I worded that wrong. What I was asking is if I should use a .050 or a .058 with that big of a saw. I will make sure everything matches up.

I run .063 on the 090, i would not go smaller then .058

 

[john taliaferro]

We use 3/8 .50 on 660 36' cuts 27'' and 3/8 63 on 088 60" . I wouldn't be scared to run .50 on 88 thats just the size of bars i ended up with .

 

[BlueRider]

pitch is a factor in figuring chain speed. If your saw is set to run .404 and you drop down to 3/8 and use the same pin size you will loose chain speed.

here are some examples assumeing 9000 rpm while under load.
.404 with a 7 pin=4242 ft/min
3/8 with a 7 pin=3937 ft/min
3/8 with an 8 pin=4500