Choosing Sprocket Nose Sizes

[JohnCusickjr]

Hi-
I looking to get a 25" &/or a 28" Stihl Type RS bar setup to use on a 361 & 460. What I am wondering about is why one would choose the 10 tooth vs. the 13 tooth nose.
The saws are used for felling & bucking up to 24" standing material and general processing of larger firewood logs.

Thanks
John

 

[computeruser]

I believe that the smaller tooth count results in a narrower nose profile, resulting in less kickback potential. By contrast, the larger tooth count makes for a larger nose profile, better suited for plunge cutting but with a larger kickback zone.

 

[ShoerFast]

For most cutting, get the 10T , as the larger is heaver and a higher kick-back rating.

The best use of the larger nose-sprocket is more for bore cutting and gets a little longer life.

Edit: we must have been typing at the same time, John, what he said!

 

[hautions11]

John, if you look closely the 25" and 28" with a 13 tooth tip are yellow or non-kickback reducing bars. The smaller 10-11 tooth tips are for the green label low kickback bars. I use the yellow label Stihl bars. The green bars are your choice for enhanced kick back safety. I do not believe they really cut a lot different. The larger 13 tooth tip sprocket will probably last a little longer. My 2c.

 

[tek9tim]

John, if you look closely the 25" and 28" with a 13 tooth tip are yellow or non-kickback reducing bars. The smaller 10-11 tooth tips are for the green label low kickback bars. I use the yellow label Stihl bars. The green bars are your choice for enhanced kick back safety. I do not believe they really cut a lot different. The larger 13 tooth tip sprocket will probably last a little longer. My 2c.

Umm, no. None of the Rollomatic S bars (non laminated, replaceable tip) are rated green. Both the wide and the narrow are listed in the same yellow column, one above the other, with an asterisk on the wide tip bar. Neither are rated low kickback.

 

[Lakeside53]

The larger is for better boring; the narrow for general work.

 

[Lakeside53]

Umm, no. None of the Rollomatic S bars (non laminated, replaceable tip) are rated green. Both the wide and the narrow are listed in the same yellow column, one above the other, with an asterisk on the wide tip bar. Neither are rated low kickback.

There is now a green rated 24/25 inch ES bar... and the tip is only a tiny bit different to that of the yellow.

 

[JohnCusickjr]

If I read the Saw Chain Selection chart correctly, it appears that there is a 25" bar that is both green, # 4030, at 10 teeth, as well as a 25" bar , # 9630, at 13 teeth, that is yellow. Both RS type. Though it seems this is not true of the 28" ( i.e. only available in yellow).
Is there something else about a given bar that is designating a yellow vs green classification other that the nose profile, i.e. # of teeth).
Appreciate all that have helped me sort out my confusion.

John

 

[Lakeside53]

Yes.. the difference is that it's been tested for kickback.... It's all a very flaky "science" IMO..

 

[smokechase II]

theory behind this

OK;
You’ all can chew me out soundly if I'm incorrect on this theory behind bar tip size and kick back potential.

The larger sized sprocket tip has an increased kick back risk because it has a greater area where the tip type of kick back can occur. {Similar thought process on the old bow bars.}

This does not mean that a smaller tipped bar could not have the greater kick back risk, depending on how the bar & chain are set up in certain woods.
Because the smaller tip bars place the tooth out even further from the raker than a larger tip on the sharper turn. (Admittedly a slight change.)

Now look at this guy from Scandinavia boring with his tip at the 2:30 minute mark. Go to http://www.skogforsk.se/KunskapDirekt/default.aspx?p=11362&bmp=11727
Then click on Film för bredband then Motorsågsarbete i stormskog (8 min)

In a lot of the dead wood that I cut, some hardwood and especially dead hardwood that I've cut occasionally, you would never consider boring at that angle of attack. I believe he is cutting spruce which is a very soft softwood.

Now the obvious caveat; Your understanding of how your saw is set up plus the knowledge of how that set up will work in the wood in front of you plus your boring technique. Will have a lot more to do will avoiding kickback during bore cuts than the tip size.

Stihl does admit on their web site that the smaller tipped bars will have greater wear in repeated boring operations.

I'm ready for my ___ chewing.

 

[JohnCusickjr]

That's an interesting site. If I could only translate!! Cool shots.

 

[B_Turner]

That's an interesting site. If I could only translate!! Cool shots.

It was interesting as they have a slightly different approach to the whole thing.

My wife gave me some pretty weird looks while I watched the vid for a second time (laptop on kitchen table) even though I couldn't understand a word of it.

 

[RaisedByWolves]

It was interesting as they have a slightly different approach to the whole thing.

Like the cut your thigh off aproach, 8:40


http://www.skogforsk.se/KunskapDirekt/Templates/WMPage____15452.aspx

 

[Tzed250]

Distance

The larger radius bar end will theoretically give the chain a longer run while in the kickback process, IMHO.

 

[B_Turner]

Like the cut your thigh off aproach, 8:40


http://www.skogforsk.se/KunskapDirekt/Templates/WMPage____15452.aspx

I want to see the Scandanavian approach to pumpkin slicing. Probably pretty good at it because with all the pretty orange gear they look a bit like a pumpkin already.