Home made Grapple

[stowester]

Hi millwrightdude. I also made a grapple based on this thread. Here is the link to my version. http://www.tractorbynet.com/forums/...-my-tractorbynet-inspired-grapple-bucket.html

After using my grapple for a couple years I would make a few changes.
My tines are 2 1/2 by 3/8 and have held up great. I would use 4" spacing for all the tines (I have some 8" in middle of the bucket). The back is 8" which is fine. I think the length is 24" which is great although I could handle 30", would not want longer then that.
I would also make my top tines curved and serrated.
I would change the leverage on the cylinder as I would like a little more squeeze sometimes.

I have used the bucket a lot. Logs, Brush, Rocks, leveling/raking, snowmobile bridge work. I love it!

Dean

 

[millwrightdude]

My loader is 57in wide and I allowed for 3in on either side. I want to make a frame similar to the pallet forks I built a few years ago.

 

[millwrightdude]

So 3/8 tines have been good for you, or would you go to 1/2. I have been thinking about 6in spacing. I could go to 4 but I think 6 is ok.

 

[stowester]

The 3/8 have been fine. I recommend 4" after seeing what stuff falls thru the 8" spaces.

 

[millwrightdude]

I look at that when I start the build. My quick attach brackets should be here today

 

[IslandTractor]

I'd go with a narrower grapple myself. My standard bucket is 72 inches. My grapple is 48 inches and perfect.

Regarding tine size and spacing, 3/8 is fine in the design I have. Note carefully the different shape of my grapple tines. They are thick at the root and tip but narrower in the middle. Custom CAD/CNC would be necessary but engineeringwise I think it is better than just a straight piece.

My tines are about 8 inches apart as I recall, maybe 9. There are times I wished they were closer but not for brush. Brush is sticky and really doesn't fall out much. Rocks are what I would like to hold onto better. I think 6 inches would be nice but remember that more tines equals more weight.

 

[jcims]

Has anyone seen a grapple with an 'overbite'? If you're picking up a bundle of small logs, at best you may be able to pinch one using the typical grapple design. I often wonder if allowing the grapple to close beyond where the tips meet the tines would help clamp smaller loads.

Another grapple design question, is there any tool to help lay out the pin locations for the cylinder and hinge? It obviously plays a key role in the travel, speed and force of the grapple, and i'm fairly certain it would be a fairly trivial trig function, but i've never really seen one.

 

[crazyal]

I'm glad others are building grapples as this is going to be a spring project for the new plasma cutter. I haven't decided as to how wide yet but most likely will be 3/8" tines 32" long somewhere between 4" to 5" tall. I'm not sure about spacing yet, somewhere between 6" and 8". But I like reading what others have done or like about what they have.

 

[crazyal]

I see most grapples have two upper claws, does anyone think three would be useful?

 

[IslandTractor]

Has anyone seen a grapple with an 'overbite'? If you're picking up a bundle of small logs, at best you may be able to pinch one using the typical grapple design. I often wonder if allowing the grapple to close beyond where the tips meet the tines would help clamp smaller loads.

Another grapple design question, is there any tool to help lay out the pin locations for the cylinder

The limiting factor on load is more the depth of the grapple and how wide it opens. An overbite would help with bulky long loads like logs but would hurt the ability to secure smaller items. The overbite might also interfere with getting close to a wall for example. Still, a slight overbite is better than underbite.

Regarding geometry of the upper jaw cylinder pin location, I imagine it is trial and error or mock up based unless you have an animated CAD program.

Upper jaw clamping force in a standard style grapple is not critical as gravity holds the load down and the upper jaw just keeps the load from falling out forwards. For a claw style grapple the clamping force is key as it is the only thing keeping the load in place.