Low kickback bars: disadvantages?

[GrantC]

I'm familiar with the tradeoffs with regard to low-kickback (safety) chain. What about low-kickback bars? The fact that, say, Oregon makes both safety and "pro" bars in most sizes tells me that there is a disadvantage to them, but so far I haven't been able to figure out just what it might be.

Anyone?

-=[ Grant ]=-

 

[techdave]

Drawback to low kick bar

There are two I can think of right off,

Major is that smaller nose sprocket is less durable than a bigger radius, and, the bar itself is not as heavy for balance with bigger powerheads.

ps-the chains would be stressed mroe turning the smaller radius

 

[SawTroll]

The most obvious disadvantage shows up when you try to bore-cut with them.

 

[PES+]

The life of the smaller radius sprocket bearing is less and also a slight increase in drag and heat.

I have a few guys here that do use the double guard tips for bore cutting for the lower kick back ability and they just replace the tips more often.

 

[Lakeside53]

Just dividing the world into into "safety and non-safety" isn't enough...

There is very little difference between say a 25 inch a stihl "green" and "yellow" bars of the same series... overlaying one with the other shows only a tiny difference in the transition from the rail to the tip. They do have bigger radius tips for logging..... but that a different series.

Green bars have been tweaked for the fictitious ANSI 45 degree kickback test (with SAFETY CHAIN); yellow have not.


Typical Stihl 3/8 low kickback bars have a 10 tooth tip sprocket, non-safety have 11, and the wide tip version has 13.

 

[oldsaw]

Just dividing the world into into "saftey and non-safety" isn't enough...

There is very little difference between say a 25 inch a stihl "green" and "yellow" bars of the same series... overlaying one with the other shows only a tiny difference in the transition from the rail to the tip. They do have bigger radius tips for logging..... but that a different series.

Green bars have been tweaked for the fiticious ANSI 45 degree kickback test (with SAFETY CHAIN); yellow have not.

"Ficticious"...I love it. "Crap" is a lot easier to spell.

Mark

 

[Lakeside53]

CRAP! Yep! got me there!

 

[GrantC]

The most obvious disadvantage shows up when you try to bore-cut with them.

How so?

-=[ Grant ]=-

 

[GrantC]

There is very little difference between say a 25 inch a stihl "green" and "yellow" bars of the same series... overlaying one with the other shows only a tiny difference in the transition from the rail to the tip. They do have bigger radius tips for logging..... but that a different series.

Well, since I don't own any creamscicle saws I wouldn't know about that...the Oregon bars are quite different, the safety versions having more taper toward the nose and a much smaller radius at the tip.

-=[ Grant ]=-

 

[crane]

would the smaller tip not be advantagous in a plung cut???
Just asking.

 

[oldsaw]

CRAP! Yep! got me there!

I guess I could say "sheet", but a Cub Scout camp I'm very well know for saying "shorts". Haven't slipped up in 3 years.

Mark

 

[SawTroll]

would the smaller tip not be advantagous in a plung cut???
Just asking.

Nope, the rakers get in the way of the cutters function, more so as the tip get smaller - and more with a RS or LG chain with the larger rakers, than with a LP. The best current chain in this regard is the RSK (slim rakers without ramps).

 

[HolmenTree]

Many large forestry companies who employ professional chainsaw employees have strict mandatory safety regulations where only small radius bar noses are to be used. These are usually always guide bars 24"and shorter. Since 1972 Oregon ,Windsor and a few others have spent millions of dollars in research and development in safety chain and guide bars. Oregon introduced the Guard Tip in 1977 and Windsor with their Mini-Pro Tip in 1979. The Oregon Guard Tip was replaced in the mid 1980s with the Double Guard Tip . These guide bars were used for consumer and large volume production cutting in professional use. The smaller bearing size reduced its durability especially when the tip was pinched in the cut with the chain still turning. But smaller kickback zone on these small tips meant less kickback energy which greatly reduced accidents on the job. Plunge cutting is slightly reduced with this style of tip.

 

[carvinmark]

Nope, the rakers get in the way of the cutters function, more so as the tip get smaller - and more with a RS or LG chain with the larger brakers, than with a LP. The best current chain in this regard is the RSK (slim rakers without ramps).

On my dime tip bars, I remove some of the back side of the cutter on the chain as well as take the rakers down because the angle the chain has to go around kind of makes the chain bounce in the cut. I get a much smoother finish from my cut this way too.
I plunge cut a lot with my carving bars, and of course they have a smaller tip to help reduce kick back and give more control to the operator. ANY bar will kick back IMHO.