Brush Grapple

abunchofidiots · Jan 29, 2020

After looking at the prices and heavy weight of brush grapples, I decided to make one that slides onto a quick attach plate just like pallet forks. The entire cost with disposables is still under $300. The weight is still light enough to not effect the lift capacity of a smaller tractor. It can also scale up to two grapples for one on each side of the frame.

saint18z · Jan 30, 2020

That looks pretty slick. I have been thinking about building something similar. Let us know how it works!

ovrszd · Jan 30, 2020

Don't be shy about bracing. I'm concerned about the claw's ability to withstand the forces applied by the cylinder.

Looking forward to seeing the finished product!!!!

4570Man · Jan 30, 2020

ovrszd said:
Don't be shy about bracing. I'm concerned about the claw's ability to withstand the forces applied by the cylinder.

Looking forward to seeing the finished product!!!!

Yes it needs some pretty serious bracing. It would have been better to be wider so it could be braced better.

abunchofidiots · Jan 30, 2020

4570Man said:
Yes it needs some pretty serious bracing. It would have been better to be wider so it could be braced better.

Wider would defeat the requirements of light weight, and quick attack pallet fork style. I'm also not sure how it being wider would allow for more bracing. There are fish plates at the joints where the 22.5 degree change takes place, not show in the pictures. That area may need made need reinforcement to distribute load away from the weld joint.

4570Man · Jan 30, 2020

abunchofidiots said:
Wider would defeat the requirements of light weight, and quick attack pallet fork style. I'm also not sure how it being wider would allow for more bracing. There are fish plates at the joints where the 22.5 degree change takes place, not show in the pictures. That area may need made need reinforcement to distribute load away from the weld joint.

Being twice as wide as it currently is would have very little affect on weight. Being twice as wide would give it a lot more ability to withstand racking sideways.

4570Man · Jan 30, 2020

Here’s your weakest link with very little ability to withstand bending sideways.

ovrszd · Jan 30, 2020

abunchofidiots said:
There are fish plates at the joints where the 22.5 degree change takes place, not show in the pictures. That area may need made need reinforcement to distribute load away from the weld joint.

The bracing at that joint may require significant bracing.

Also not sure of the gauge of square tubing used? Pretty good chance you are going to bend the outer section?

As 4570 pointed out, the racking is going to start at the hinge. If the claw holds up to the stress, the channel iron may twist. Channel has little resistance to twist.

Start using it. Any weakness will show up quickly.

I had to backtrack and reinforce my claws twice. After a few years of use I also had to rebuild the hinge areas.

Someone much geometrically smarter than I can tell you how many lbs of force you are applying to each area.

4570Man · Jan 30, 2020

ovrszd said:
Start using it. Any weakness will show up quickly.

.

The downside is it’s a lot harder to fix once it’s bent.

ovrszd · Jan 30, 2020

4570Man said:
The downside is it’s a lot harder to fix once it’s bent.

Absolutely!!!!

I understand wanting light weight. But that's secondary to dependability.

4570Man · Jan 30, 2020

ovrszd said:
I had to backtrack and reinforce my claws twice. After a few years of use I also had to rebuild the hinge areas.

.

That was the same areas my cheap grapple failed. My Favor grapple is designed much better to prevent it.

ovrszd · Jan 30, 2020

4570Man said:
That was the same areas my cheap grapple failed. My Favor grapple is designed much better to prevent it.

Yep. I underestimated the power of hydraulics. I use the snot out of my Grapple too.

abunchofidiots · Jan 30, 2020

Keep the info coming guys. This is my first grapple build. It is intended use is for moving piles of Autumn Olive brush.

4570Man · Jan 30, 2020

Here’s the lid on my Favor grapple vs my titan grapple that was junk. The favor lid is boxed all the way up the center to prevent racking sideways, the cylinder is on a double mount vs one in the center, there’s a stabilizer tube all the way across the pins, and it’s ar400 that’s a lot stronger. The titan in the google image looks improved over the one I had. The cylinder mounts on mine were still the single post ones but they were cut out of the grapple body and 2 3/8 plates stacked. One 3/4 would be a lot stronger than 2 loose stacked 3/8 ones. It looks like they’ve added that tube across the back too. Mine just had the side plates spanning a good distance. Overall not much to keep the lid from racking sideways. It wouldn’t take a lot to withstand clamping a nice round log but clamping on only one tip of the lid or worse a slanted object that pushing it sideways is much harder to withstand.

ovrszd · Jan 30, 2020

And, even though the original intent is just some light brush, that changes quickly.

ptsg · Jan 30, 2020

I'm a bit concerned about the tubing you're using. Seems a bit weak for that cylinder.

Usually the first project with hydraulics will requires some redesign or reinforcement after the first couple of tests. It happened to me on my backhoe and I'm pretty sure it happen to everyone. It's very easy to underestimate the power of hydraulics.

I'll leave a couple of pictures of a style of grapple we use here. It's designed to handle logs more than brush but it should work fine as well.

Anyway, keep up the good work. We're here to help with suggestions and tips. :thumbsup:

4570Man · Jan 30, 2020

ptsg said:
Usually the first project with hydraulics will requires some redesign or reinforcement after the first couple of tests. It happened to me on my backhoe and I'm pretty sure it happen to everyone. It's very easy to underestimate the power of hydraulics.

:

I practically have a degree in busting implements.