V cut question?

L

Leafguy

New member
Hi,

When you guys use the V-cut is it typical that the saw gets pinched as you finish the cut? Hopefully that makes sense. Maybe I'm missing a step. On my last crane job I was practice this cut and got the saw pinched for a moment before the piece was lifted off.

Thanks for any advice.
 
Often times the saw does get pinched for a moment, but if you orient your cut the right direction, and finish your cut from the correct side, you can keep that from happening. Also, it helps if the crane operator has the right amount of tension on the cable, to take the full weight of the peace as you are finishing the cut.
 
What Reach said. It helps to meet up your cuts on the far side of the wood first, and leave the last fibers closest to you to the end. It’s easier to read the kerfs and make an educated decision as to when and where and how your saw may get stuck and to avoid it altogether.

The crane operator can only influence the piece in indirect ways as it relates to a stuck saw. It is often an ungraceful moment trying to move the piece about with the crane while the saw remains pinched. I find this is especially true when a piece has rotated and is still connected to the tree. How you sling the piece, and where your cuts are pointing, will determine your success at avoiding this kind of movement.
 
All of the above. Much of your question depends on the crane op, and how well the weight of the piece has been estimated for pretension. Maybe the crane does or does not have a LMI by percentage or an actual numerical value. I love that my crane has both.

That said, if the crane op is close to proper pretention, and location over the COG of the pick, and does not adjust anything, I would watch for this:
- Sag: watch your first kerf and see if it is opening or closing. If your first is opening, it’s more difficult to avoid the pinch on your second cut without plunging toward the end.
- Rotation: If this seems to begin as you make the cut, consider positioning so the cut opens on your side as the cut continues. If it closes on your side, the bar will surely get stuck.
- The steeper the angles of the V, the less you’ll feel any pinch.
 
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Stumpsprouts said:
How steep a cut do you go for?
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Aiming for about 90 degrees interior angle, but it’s not always 45/45. Much depends on the angle of the piece. The closer your saw is to vertical on the second cut, the less pinch you’ll feel.

@Stumpsprouts , this is not directed at you, just in general…I think it’s important to remember that the V technique is designed so you can leave the area prior to liftoff. If the pinch is holding your saw, and you can’t get it out of the kerf prior to lift, you may really need to reevaluate the sling setup and the hook’s relation to COG.

I talked to a good number of people about the spider crane this weekend at expo, and a lot of cut techniques were brought into discussion. Bottom line is that until you’re really nailing the whole picture, learning to watch the kerf and use some plunging accordingly as you finish, you can fudge through some gray area. If your overall setup is way off, there isn’t a cut technique that will help you.
 
I try to get the operator to apply less tension for a v cut than a normal straight thru. IE if we think the pick is 2000lbs we'll put 1500 on it. Since the v will more or less hold the pick in place, you can cut all the tension wood without the pinch and then have the op dial up the tension to lift it off.

As others have mentioned, cut your compression wood first, then the tension. Don't be afraid to over-overlap, if that makes sense. Use different cuts for different picks, the v is great in certain situations but straight thru or a shelf are great tools as well. Cut slow and look up.
 
Z'sTrees said:
I try to get the operator to apply less tension for a v cut than a normal straight thru. IE if we think the pick is 2000lbs we'll put 1500 on it. Since the v will more or less hold the pick in place, you can cut all the tension wood without the pinch and then have the op dial up the tension to lift it off.

As others have mentioned, cut your compression wood first, then the tension. Don't be afraid to over-overlap, if that makes sense. Use different cuts for different picks, the v is great in certain situations but straight thru or a shelf are great tools as well. Cut slow and look up.
Click to expand...
This is key, get the ball where it needs to be for your rigging, sling it up well and get familiar with reading the movement of the piece based on your rigging as well as watching the kerf, compression wood first then tension wood. Remember that a crane is really only designed to lift up vertically any lateral movement is on you to influence with your rigging and cutting.
 
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