i like coming down into the cut straight on top of under cut; often previously taking some material from sides, straight into bottom cut (do this after bottom cut, or else risk sooner pinching of the bar). This safely reserves the most leveraged wood holding the limb in place (from above, directly behind), while taking some of the side 'meat' out, allows faster backcutting on backcut (due to same power having less wood to cut). On larger limbs i might bore in and down for bottom cut, perform side cuts; use side cut(s) for speed and balanced pulls; as well as total alignmeant tool with bottom cut for backcut.
You can always slow saw cut down if ya want, but availing yourself to full speed/power over resistance to wood toughness and volume must be pre-thought i think. With that speed you can get a cleaner throw or snap if chosen, at more points of sudden decision than without the pre-backcuts(sidecuts etc.) after face cuts or faster/ more powerful saw.
i think that the taking of the saw is more prevalent when topcut extends beyond bottomcut (as in Sherril cartoon?)? In fact only remember having that problem with top cut towards trunk from bottom cut grabbing saw was with larger decayed wood; though i like to hinge mostly. And look at this as full kerf dutchmans or modifications, from the 'early interuption in face'; with the spar at totally different angle, and backcut generally not as far progressed (unless you correct for that with faster final cutting/ less meat setup) eliminating most leveraged wood against fall.
When cutting like this to snap off a horizontal, if you cut across on final backcut (rather than straight down), the remaining wood in 'hinge' of kerf face, pulls the force to it's side, slamming the faces together on that side only, and possibly throwing it the opposite direction (than you pulled from with pattern of cut). A very simple example of the power of the slamming faces isolated without hinge travel to pull from; throwing to the opposite side. There was about no hinge to ride and pull, so the final lil flap at failure places all the force rebounding off the connected side of log below the uncut wood. Doing same with felling very dangerous, higher leverage, weight, speed; tree at differnt dis-position when faces close than horizontal limb with same technique applied at that angle and class. i would think narrow Humboldt would be safer than narrow conventional; and if already playing in that danger area, would try a buried kerf into that narrow face; but total head travel/space must be free and open; as this would put high leverage confinement to motion on hinge, with slow speed, early closing faces; baaaaaad mixture IMLHO.
i also think 1/3 is good undercut guide, but that the % of undercut really depends on the wood strength and the leveraged load. ie. the same cut won't work with the same approx. weight tripled or extended 2x as far out or with weaker wood. It should all be observed and learned from with each cut, for all the factors would matter IMLHO.
i think a bigger saw generally denotes a bigger tree with more force to take against ya. Also the length of the saw giving that force a quicker snatch from ya!
Or something like that.
:alien:
