Home made Grapple

[2458n]

Since this is a real old post- could I ask where you bought your quick attach boxes?

 

[deerseeker001]

great job.

 

[fxrupr]

Just asking here. I have a B7500 HS Kubota TBL. The rated lift of the bucket at the pivot pin is around 600 LBS. Seems like the heavier you make the grapple the less load the tractor can actually pick up. What is the optimum design of a grapple for strength and lightness?

 

[Xfaxman]

Just asking here. I have a B7500 HS Kubota TBL. The rated lift of the bucket at the pivot pin is around 600 LBS. Seems like the heavier you make the grapple the less load the tractor can actually pick up. What is the optimum design of a grapple for strength and lightness?

This is it :thumbsup:. http://www.tractorbynet.com/forums/attachments/283444-single-lid-cut-wicked-grapple.html

 

[IslandTractor]

This is it :thumbsup:. http://www.tractorbynet.com/forums/attachments/283444-single-lid-cut-wicked-grapple.html

Yep, for a B7500 that grapple is exactly what you want. Do you have a quick attach mount?

 

[ChristmasTreeFarmer]

I found this thread recently while comtemplating purchasing or building a grapple. This grapple is awesome!...and it gave me the confidence to build my own. In fact, I have a 10-year old son whom I want to teach to weld, and more importantly teach that we men don't have to buy everything in our lives.

But...I have a question. I have seen some grapples with a design similar to this, where the bottom tines are 25-30" or more long. I have seen other manaufactured grapples where the bottom tines look to be 12" long, and the back of the grapple is much taller. It seems that the latter design would be stronger, but would put more reliance on the top grapple for holding the load (which is probably already pretty important)

I am hoping you guys with experience can give me some advice on this topic. I will be using the grapple to pick up logs, brush, some rocks, etc. The first primary use will be to clean up some log/dirt piles on my property left by the excavator. He used a dozer, and too much dirt was mixed in with the logs...preventing a full burn. I need to sift the remaining logs and brush out from the dirt, pile them, then burn them.

For reference, I have attached a picture of the newer model grapple I am referring to

 

[IslandTractor]

I found this thread recently while comtemplating purchasing or building a grapple. This grapple is awesome!...and it gave me the confidence to build my own. In fact, I have a 10-year old son whom I want to teach to weld, and more importantly teach that we men don't have to buy everything in our lives. But...I have a question. I have seen some grapples with a design similar to this, where the bottom tines are 25-30" or more long. I have seen other manaufactured grapples where the bottom tines look to be 12" long, and the back of the grapple is much taller. It seems that the latter design would be stronger, but would put more reliance on the top grapple for holding the load (which is probably already pretty important) I am hoping you guys with experience can give me some advice on this topic. I will be using the grapple to pick up logs, brush, some rocks, etc. The first primary use will be to clean up some log/dirt piles on my property left by the excavator. He used a dozer, and too much dirt was mixed in with the logs...preventing a full burn. I need to sift the remaining logs and brush out from the dirt, pile them, then burn them. For reference, I have attached a picture of the newer model grapple I am referring to <img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=344080"/>

The grapple type your photo shows and you describe is known variously as a claw or rake or RBG or clamshell. It is indeed quite different from the more common longer bottom tine grapple. The claw style grapple works essentially the way your hand does when you pick something up with finger and thumb when fingernails are pointed up. You must use your thumb in a pinscher grasp. The thumb holds the item firmly against the finger and that allows you to lift the object. The long bottom tine style, variously called open bottom, L shape, and other names works the way your hand does when you scoop something up with fingernails pointed to the ground. Gravity keeps the item in your palm and the thumb just steadies the load. Indeed, you can even lift something without the thumb so long as the item is balanced.

Both grapples have advantages but in general, the open bottom or L type is less expensive and can carry a larger load of solid irregular sized objects. Same as your hand. See how many pencils you can grasp with fingernails up. You can certainly pike more than that into your open cupped palm with fingernails pointed down.

The claw style excels at grabbing brush or at picking up small debris. It also holds a single log more securely.

The open bottom style holds much more volume so you can load multiple logs at one time. You can scoop more because you can get the bottom tines under objects. Because the top grapple jaw just stabilizes the load, you can grab one item, move to another spot and grab another easily without having the first item fall out when you open the top jaw a second or third time. Indeed, you can lift and carry something like a big rock without even closing the top jaw because gravity holds the load in place.

Another major difference between the two basic styles is cost. The claw type grapples are much more expensive and heavier because they require full width upper jaws that have to be just as strong as the bottom short jaw. With the open bottom style the top jaw just stabilizes the load so it doesn't need to be as heavily built as the bottom jaws.

Weight is another difference. Claw grapples weigh more so your net lift capacity is less. Not an issue for brush but it can be for rocks and stumps and logs.

In general, unless you have a specific application or reason to have a claw type, the open bottom style makes more sense for most people.

 

[Xfaxman]

I found this thread recently while comtemplating purchasing or building a grapple. This grapple is awesome!...and it gave me the confidence to build my own. In fact, I have a 10-year old son whom I want to teach to weld, and more importantly teach that we men don't have to buy everything in our lives.

But...I have a question. I have seen some grapples with a design similar to this, where the bottom tines are 25-30" or more long. I have seen other manaufactured grapples where the bottom tines look to be 12" long, and the back of the grapple is much taller. It seems that the latter design would be stronger, but would put more reliance on the top grapple for holding the load (which is probably already pretty important)

I am hoping you guys with experience can give me some advice on this topic. I will be using the grapple to pick up logs, brush, some rocks, etc. The first primary use will be to clean up some log/dirt piles on my property left by the excavator. He used a dozer, and too much dirt was mixed in with the logs...preventing a full burn. I need to sift the remaining logs and brush out from the dirt, pile them, then burn them.
-------------------------------------------------------

:welcome: to TractorByNet!

I think either design would do what you listed. I have had both styles, sold the claw or clamshell style and bought the L bottom grapple. I can move more brush with it.

 

[ChristmasTreeFarmer]

Awesome answers to my question! I'm very new to this site, and I'm afraid I'm already hooked. We have 54 acres and cleared 8 acres last summer...spent days with a borrowed rock rake cleaning it up before seeding. Now I see a post for a land leveler...that would have been awesome!

Back to the grapple. I have seen one video that suggested putting the bottom teeth into the ground 5-6" at just the right angle in order to remove surface roots. That same video featured a grapple whose support pipe (pipe near the end of the bottom tines) was nearly the diameter of the bottom tines, which made it easier to do this as the pipe helped kep the grapple from digging too deep. This seems like a great concept to me, but I wonder how useful it would be.

Most of the grapples I have seen on this site feature a rod connecting the bottom times (drilled through all tines) and gussets going from the rod to the tip of each tine. This seems very easy and strong, but I think it would effectively prevent the rooting operation mentioned above.

I have a 27hp Kubota with FEL. I'm thinking I will build the L type grapple with bottom tines 24-30" long. Advice on length would be appreciated. I'm thinking about 48" wide with tines 6, 8, or 12" on centers. We have a clay soil here, so I am thinking wider spacing would be better so as to not get clogged...but this would not be needed during most of the tasks I will be doing. Again, advice on tine spacing is appreciated. I would like to use 3/8" x 2" for the bottom tines, but I'm thinking this might not be strong enough (seems most on here are 2.5" or 3", and even 1/2 thick). I've thought about doubling up the ends of each tine (last 8" or so) in order to give more strength there while trying to keep weight down.

I really respect the opinions of the experts on here, but it would be great if those opinions were that the rooting operation was rarely useful (seems easier to build with gussets), that I should make the bottom tines x long, that 3/8" x 2" would be plenty strong, etc. I also wonder about using 3/8 x 2 for the center tines, and use 3/8" x 3" or 1/2" x 2" for the outside tine on each side.

 

[IslandTractor]

Rooting is a term that gets thrown about a lot but it is better to be specific. If you are talking about grubbing the roots from a single or multiple trees, you really wouldn't be inserting the grapple tines six inches and blindly moving forward. You would instead be pushing on the tree to expose the roots and then selectively sticking the grapple under where you know the roots are before curling and slowly driving to rip the root.

What you seem to be describing is kind of a front end plowing or root raking the way a bulldozer would. Not a great idea with a CUT as the FEL is really designed with lifting rather than pushing in mind. Long skinny offset arms on a tractor loader are quite different from the stubby thick inline arms on a bulldozer. A CUT will do it but you risk damage to the grapple or FEL if you hit something immovable with a lot of momentum. A subsoiler or chisel plow would be better for blindly clearing old roots.

3/8" is plenty for a grapple on a 27hp tractor but I would suggest 3" rather than 2" tines. . I've never seen 2" used. Tine spacing depends in how you intend to use it. If you primarily are hauling brush and logs or stumps then 9-10" spacing is fine. If you want to carry cut firewood or collect smaller debris and rocks, then 4-5" is better. One compromise is to make the main tines 10-11" and the
put lighter shorter intermediate tines in between. The light tines just keep
Stuff from falling through so don't need the strength of the others.

The pipe reinforcement near the tine tips does provide a lot of support. It doesn't really work that well as a depth limiting device though as the down force on the tips tends to pull the pipe into the ground where it pushes rather than surfs over the dirt.