I want to build a tree shear.

[Rio_Grande]

He concept is simple, but I want to be able to cut approx 12 inch trees off within a couple inches of ground level. I like the style that is like a big pair of scissors with one side having a hawk bill shape, cutting edge on the other side. Where my problem begins is I can't bend the steel, so everything has to be plasma cut and welded. All I have to machine the pivot point is a drill press. Kinda limited in the machine tool department.

 

[J_J]

Here is a link to some tree shear pictures that I posted a while ago.

http://www.tractorbynet.com/forums/build-yourself/233021-starting-tree-brush-shear-build-3.html

 

[Rio_Grande]

Thanks JJ I saw those. I need to figure out the pivot pin. Not sure how tough it needs to be to cut 12 inch.

 

[JerryG]

Just something to think about. You are going to need a good size tractor for a 12" tree shear.

 

[Rio_Grande]

I plan to run it off of my ctl 70

 

[Domush]

All I have to machine the pivot point is a drill press. Kinda limited in the machine tool department.

Easy means for a pivot point is to plasma cut a rough circle, then weld in a short piece of pipe and use a slightly smaller diameter steel bar as the pivot. Don't kill your drill press (and bits) trying to drill a hole that massive.

 

[Rio_Grande]

I have done that on several different projects, but nothing that has to hold the kinds of force this will require. I am thinking I should make the framework from at least 3/8. If I gusset it properly it should be tough enough and my plasma will cut it fine.

I think I want a double shear as opposed to the single style. Double the fab, double the parts but it looks like it would be tougher in the long run. I noticed the bigger shears seem to be made this way. I like the one JJ attached to his post earlier, simple and minimal machining required. The problem is the two big heat treated jaws that have to be machined and tapered before assembly.

 

[swick1]

The junkyard shears only have one moving jaw. I think 2 jaws are more for staying centered while closing and looks than anything but I don't have any experience with them

 

[smiley]

I have no knowledge on this subject but in thinking about it, would these weld on 3 pt lift arm ends simplify the dilemma of the pivot point, with the stub extended and your blade welded at 90 degrees? Maybe even a second one on the other end to attach the cylinder?? I think it would take some serious welding however you do it.
THREE POINT LIFT ARM REPAIR END WELD-ON TLS311F | eBay

 

[Leejohn]

Man he is getting more then retail + shipping. You can get them at any farm store for less...