Rigging a Block

JOe ,

Off set your block from the face cut or vice versa. If the tree you are blocking down has a lean , well you dont have to worry about it to much . If your dealing with a straight stick , such as a conifir, use the method above or let it run to eliminate the slamming against the trunk problem .In most cases, it's not the block I worry about . Because the distance from wich your rope runs through the block and is tied off, the weight of the log and any line stretch will bring the piece below your block .You can also use slings with carabiners and or pulleys along the trunk to off set the so called static end of the line to eliminate the log from pinching the rope.

Greg
 
Even on a vertical, the direction of the loadforce is going to be down, but generally would have to be across horizontally to pinch line; to sieze system.

Forces are seriously reduced if you make no kerfs/ cross cuts in face, and muscle the load over as much as possible by groundman with line, as slowly as possible on a wide face hinge, before the line/pulley system takes the load and impact at 2:1 (unless load so long it's leveraged length becomes a factor). If you make a crosscut/kerf in face; after hinge just folds, the kerf closes, and the groundman's pull doesn't go to force more tensioned support fiber, but more compression support fiber; but this is pushing back against the direction you are trying to fold hinge; instead of pulling back. In either case the extra pull by groundie forces extra responding force in the tension and compression in hinge. The compression point precedes and makes more differance than the tensioned to the tree's support, so Nature uses it first, throwing off control by the tensioned fibers, so we craft face so Nature can't take earlier pivot than we intend, by not allowing a kerf across face to close against us. If it does, this puts the control in the face where the saw can't reach, instead of at the backcut/ operator's area. When you trigger the backcut to release, there is no gradual release of fibers over a stretch of hinge fiber to the closed pivot of the kerf you made, but empty space; so system goes from a lot of tensioned, leveraged support away from the pivot of the closed kerf, to suddenly none. Without a kerf in face/crossed cuts/dutch, there is no distance without fiber between the tensioned fiber and the compressed fiber, so release is more gradual. Wide face as final constraint on time hinge can hold on, allowing fuller use of the effect.
 
Trust me Joe, that's the least of your worries. It should sail past the block no problemo, lessen you're rigging with cable.
 
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