what makes a safety bar (green bar versus yellow)

[Nine6Teen]

newb here ... what are the design differences between a low kickback bar, and a not-so-low kickback bar ? nose diameter ?
and on a related note, what is the most important factor when making a boring cut ( in terms of chain type, bar type, etc) is it easier to bore with semi-chisel ?

 

[Chainsaw Jim]

Safety bars have narrower tips to allow the safety bumpers between the teeth to thrust outward keeping the teeth from touching the wood. You cannot do plunge cuts with a green chain but if you have a yellow chain on a green bar you'll be fine.
You might prefer full comp for bore cuts. Skip can get chattery and jump on you.

 

[Definitive Dave]

A strong saw with a smooth power band also helps with clean bore cuts.
Of all my saws, the MS441 bore cuts the smoothest, even though it is far from the most powerful, as Chainsaw Jim points out semi or full skip will be jumpier in getting the bore cut started, though they might clear chips better once you are in the wood.
Dave

 

[James Miller]

That little orange spec in that giant mulberry is my cs490 bored in with the factory safety chain you can bore cut with some green chains I had nowhere to sit the saw its all briers and ground vines. I would practice bore cutting with the saw horizontal that way if you do have a kick back it swings the bar away from you instead of up towards your chest and face like a vertical kick back would.

 

[rmh3481]

The easiest way to plunge cut is to start at the base of the bar tip and rotate in. Keep your rpm up and expect some movement. Practice makes perfect.

 

[Philip Wheelock]

On plunge cuts:
1. Most important: Make sure the cutters are good & sharp and the depth gauges on the money. Begin the cut at the lower quadrant of the tip and rotate in as the tip is buried. Always use your own chains so you won't get surprised by how they react in the cut.
2. Full comp chain will be easier to control.
3. For some reason, I've found that a chain will get jumpier in a plunge cut as it gets close to the end of its service life.
4. Haven't noticed any difficulty using green "safety chains" for plunge cuts.
5. Keep your body out of the path of a possible kickback when beginning vertical plunge cuts; on horizontal plunge cuts, tuck an elbow into your body in case the saw tries to launch back at you.