It`s no wonder you are so confused if your "service depot" doesn`t possess any greater knowledge than you have displayed regarding this bar. Honestly, if they don`t know that bars aren`t "compatible" with a specific sprocket size, how much do they know? You can use either a 7 or 8 tooth drive sprocket as long as your saw will pull it ok. It would be very unusual for a bar with an 11 tooth sprocket nose to have a tail too narrow to accomodate the 8 tooth drive.

From the info that you have given I can surmise that you have a replacable sprocket nose bar currently prepared to run 3/8 pitch .050 gauge chain on an 11 tooth nose. 3/8(p) and .404 are both pitch dimensions and a bar nose can`t be both, either it is for 3/8 pitch or .404.

im thinking a 3/8p with .404 chain. wha other comboe will work well?
Huh??? The chain will be either 3/8 or .404 pitch. From the info you have provided, the bar is set up for 3/8 pitch .050 gauge chain (Stihl 33RSC or Oregon 72LG)which the saw has more than ample power to pull. It will handle .404. 063ga easily, that was more common on this model here, but you will need to replace the bar and drive sprocket rim.You could change the bar tip and drive sprocket to .404 and run .050 chain with your bar but that is not a common size.

This is for your 051, right?

You can go either way - 3/8" or .404" pitch chain. I run 3/8" .063" gauge on my 075 and 076 with good results on 24" to 42" bars. Stick with an 8-tooth drive sprocket with 3/8", 7-tooth drive sprocket on the .404".

Bailey's has a number of bars listed on their website that will fit your saw, and even more if you call 'em up and ask. Most Stihl dealers don't deal with the large-mount bar on a regular basis so they may not know what's going on with the big Stihl saws.

it should have read 'more' compatible or better suited. if im replacing the sprocket i have a choice of what to replace it with.

my point in questioning is that i have a choice of either 8t or 7t sprockets, ideally id like to used this bar/tip(have this, thus no cost) but will go to .404p if it is a better choice.

as to changing the sprocket size, i assume the 8t sprocket is larger in diameter and this would lower the torque but increase the chain speed?

sorry for confusing post.

dave

COMPUTERUSER. This post was a long time ago but hope you still monitor it. I have 076 AV that I run Alaskan mill and Sperber. The Sperber bar is .404 with a .063 gauge chain that I run on both. I have two 076AV and want to have the ability to run 3/8 but I know I need to change the sprocket, but wondering if it is more complicated than just the sprocket? I have a 3/8 inch bar 32 inches, that I thought was a 404 for the McCullough's have. The bar was bought off ebay, but came in 3/8th. I'm stuck with it but would like to have the smaller gauge for the milling. Any idea on that. It had.404 when I bought the Sperber package used. So I kept using the .404 chain. I have about 30 logs mostly Indian rosewood and Russian olive that I acquired and they are smaller logs, I would like to change over one of the 076's to 3/8s .050 gauge. None of the Stilths reps know or will even give the time of a day on something they did not sell or do no service.

I was able with the help of an Oregon rep locate the part number for the 3/8th drum that will fit the 076. I also found the rim sprockets. I also ordered a bar that was for sale at 30 dollars ( at this price even without sprocket tip it was a good deal) it will run .404 or 3/8th pitch and is .063 that was a 20-inch bar. Not having a sprocket tip will add drag. With the 076 that should not be a problem. I can use this with the Grandburg small log mill. One reason I wanted to go with the 3/8th pitch is the availability of the bars and chains under 30 inches, and the cost of a .404 bar is always over 150 dollars or more. In addition, I want to use the bar Granberg sells 3/8 pitch tip with a .063 chain. It has a sprocket tip, and not laminated which Granberg does not suggest on the small mill since the mill uses two bolts to hold the bar.

The problem I have with changing gauges is the climb or dive cuts you get not having the exact chain size for the grooved of the bar. If I have any problem with chainsaw milling it is the climb and dive cuts that ruin the board. I just had that problem with a .058 chain in a .063 bar, and just got terrible cuts to a point the mill just stops cutting. Just that small difference in chain gauge creating real trouble. I inserted the .063 and cut fine. Your post seems to say you can use either gauge on a .404 bar. Do I have that correct? You don't have any problems?

I have seen some cutters use .325 pitch with .063 guage chain ( small tooth heavy chain ) unless they were really stressing their bars I could not see the advantage other than less stretch & breakage potential . Running .058 chain in a .063 bar would give you really poor cutting . I always use .404 chain with .063 bar for conventional hardwood cutting , milling .404 with .080 solid tip bar with auxiliary oiler , bar & chain last forever !

I found a small 21-inch bar .063 with a solid tip based on you staying with the .404 pitch rather than spend 90 dollars on the 3/8th .063 with gear tip at this point and see how this works on my 076 with the small log mill for cutting 1-inch ruff boards. The bar was 30 dollars. So at least I got a deal on ebay.

Awesome let me know how you like it , ensure to run winter grade oil (thinner oil) it will ensure adequate flow , for the larger chain . Some put in a bigger oiler , or an auxiliary external oiler drip . You will know soon enough , heck a oil can with bar oil & kerosene mix works also !