Root Rake/Grapple For Kubota B2910

   / Root Rake/Grapple For Kubota B2910 #1  

rswyan

Super Star Member
Joined
May 12, 2004
Messages
11,241
Location
Northeast Ohio
Tractor
Kubota B2910, Cub Cadet Pro Z 154S, Simplicity 18 CFC, Cub Cadet 782
I'm planning on building a grapple to use with our Kubota B2910 ... in fact, I've started. The intended use will mostly be debris clean up (logs, brush, etc.) and, to a much lesser extent, actual brush removal. There are only two areas where I need to do actual brush removal:

1. Roughly a 10' to 15' swath that runs 600' along a fence line. The previous neighbor used to keep this mowed and the brush beaten back (he installed the fence) ... but he sold the property and the new neighbor isn't interested ... don't blame him (it's my property, not his) This area is completely overgrown ... the brush (multiflora rose and who-knows-what) is probably 7' tall at this point and incredibly dense ... you can't even walk the fence line on my side of the fence.

2. Another 360' that is owned by someone other than myself (city, county, etc.) along the "road" that runs to our house. This one has become my headache basically because we are the only people that have an address on this "road" (it's really just our driveway ... and the road didn't even exist until Pops cut it in and graveled it) and the utilities (electric & phone) to our home run down the right of way. I usually keep about 10' - 15' of it that is in grass mowed, although the city has started to mow it occasionally (not often enough to suit me) but the area underneath the poles has gotten out of hand (it was never grass AFAIK) and has become totally overgrown, with trees and vines growing up into the wires (including vines on the top power wire)

Trying to get the utility companies to do anything about it is fruitless ... the phone company won't touch it, because they are the power company's poles ... and the power company - who I've contacted repeatedly over the years - usually says it's on the upcoming schedule. Then the derelicts that they subcontract the work to come out and do a minimal amount of work, leaving it in a condition that it's sure to be a problem again within the next 12 months ... if they even do enough to actually handle what is currently a problem. They were here some time earlier this year ... still had grapevine growing over my phone wires - and, if memory serves - vines growing into the top wires on at least one pole after they left. I've sprayed the grapevine since and the portion of it that was on my phone lines is largely dead ... but there is plenty more that was right behind it that is headed up towards the phone wires.

I'm going to tear the brush out under the poles, maybe spray anything that's left, then grade it and seed it ... and keep it mowed after that.

The style of grapple I am building is a root rake "clamshell" type. I haven't totally finalized all aspects of the plans yet, but it's modeled after WR Long's RGB2-48 grapple ... with a couple design changes and modifications. Two of the primary ones being cylinder sizing and placement.

The picture below is of TBN member NHBotanut's RGB2-48 mounted on his B7610 (which is the next size smaller tractor than mine), and who has helpfully provided me with some basic dimensional info on his unit:

WR Long RGB 48 Grapple.jpg
 
   / Root Rake/Grapple For Kubota B2910
  • Thread Starter
#2  
Today, while working up in the shop cleaning and organizing, I cut the 5 "teeth" for the upper jaw assembly (along with some other stuff :D)

The two outboard teeth will be welded to the jaw arms. The three inboard teeth will be welded to a piece of 2" (2 3/8" O.D.) Schedule 80 pipe that passes thru all 5 teeth (as depicted in a picture further down in the thread)

These are made from 1/2" x 3" flat bar ... and are 13 1/2" long at their longest point.

You can see I used a 45 degree cut ... I'm doing that a lot ... mainly because I think that: 1. it will achieve what I want it to, 2. it maximizes material usage, and 3. it makes things easy.

Tonight after dinner I stuck the three inboard "teeth" in the drill press and drilled a 1/4" pilot hole, 1 1/2" in from the end, and 1 1/2" down (or up) from the top/bottom of the bar edge. Then I chucked up a 2 3/8" Lennox Bi-Metal hole saw and "kissed" it to provide a visual reference:

IMG_1434.jpg
 
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   / Root Rake/Grapple For Kubota B2910
  • Thread Starter
#3  
After that I fired up the plasma cutter and using the circle cutting guide trimmed the end of the three inboard teeth.

I'm afraid I don't have much experience yet using either tool (the plasma or the circle cutting guide) ... so the quality of the cut isn't the best. Close enough for my own purposes though:

IMG_1436.jpg
 
   / Root Rake/Grapple For Kubota B2910
  • Thread Starter
#4  
Then after trimming the inboard teeth, I took them back to the drill press and drilled out the 2 3/8" holes with the Lennox Bi-Metal hole saw on all five teeth:

IMG_1439.jpg
 
   / Root Rake/Grapple For Kubota B2910
  • Thread Starter
#5  
After that was all said and done I grabbed the 2" Schedule 80 pipe (along with some additional triangular "teeth" :D) that ended up as a "just-the-right-length" drop from an 11' stick of pipe and this was what we had (it's actually upside down in the picture from the way it will normally be oriented):

IMG_1443.jpg
 
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   / Root Rake/Grapple For Kubota B2910 #6  
Randall,

Nice work so far. What do you estimate the weight of the grapple to be when you are done? I believe mine is in the neighborhood of 375.
 
   / Root Rake/Grapple For Kubota B2910 #7  
Ok, I just looked it up. I was off 50 pounds....325. I also bumped up the pressure relief by adding a shim ( or i should say the shop did ). I did this specifically for lifting my snowmobiles with the pallet forks so I could move them around.

Just don't make it too heavy as you will loose lifting capacity.
 
   / Root Rake/Grapple For Kubota B2910
  • Thread Starter
#8  
Mike,

Thanks.

I'm estimating the weight will end up being in the neighborhood of 350 - 375 pounds ... just based on the weight per foot of the various steel components I'm using.

I need to do the shim on the relief valve thing as well ... I've never even checked it ... even though I have a gauge to do it.

Definitely intend to keep it as light as possible.

I need to see if I can recover the grapple plans I did awhile ago in my 3D CAD program off of a backup (had a hard drive crash on my desktop) ... a friend of mine offered to run some calcs on them in the simulator in Solidworks which he's working in today.

I really need to do it (recover the file) so that I have an actual plan I'm working off of ... which will hopefully prevent any screw ups when cutting the steel components. Also the cylinder placement and the placement of the hinge pin for the upper jaw are critical ... so I need to have that figured out before I get in too deep.

I'm planning to move the hinge pin for the upper jaw forward a good bit of where it's located in WR Long's design.

Today I have to replace the load center in the shop, which is really inadequate for what I have going on in there. The current panel, while it is 100 amp, only has 4 spaces (breakers) ... and I can't even have the plasma cutter and the air compressor wired into it at the same time. Hopefully replacing that will go smoothly and not turn into a fiasco.
 
   / Root Rake/Grapple For Kubota B2910
  • Thread Starter
#9  
I'm having some difficulties (due to a hard drive crash) with accessing (or even finding) the CAD file I had going on this from a couple of years ago ... and rather than spend a lot of T & E on trying to recover it, I decided that since I have the CAD program available, it would just be easier to rebuild it from scratch. So that's what I did last night.

Critical thing (for me at least) in designing, is figuring out the design/placement of the cylinder attachment points/pins and the hinge pin/pivot point for the jaw. Gotta have those correct for a working mechanism ...

It's largely dependent on the retracted and extended lengths of the cylinder, the cylinder's stroke, and how much jaw opening you want to have.

Below are the results from last night's efforts. The color key is as follows:

Dark Grey = Lower Frame

Green = Upper Jaw Open

Red = Upper Jaw Closed

Beige/Brown = the two circles the cylinder's rod end attachment point makes when it's extended or retracted, and rotated 360 degrees around it's mount point on the Lower Frame.

Purple = the arc the cylinder's attachment point on the Upper Jaw makes as the cylinder rotates and goes from extended to retracted (or vice versa)

Major Grid Lines = 1'

Minor Grid Lines = 1"

Grapple Side Profile.jpg

Next thing to do after I finalize the side profiles and am certain I'm happy with the design and functionality of the mechanism, will be to fully model it in three dimensions. That will essentially provide a set of plans to work off of in building it.
 
   / Root Rake/Grapple For Kubota B2910
  • Thread Starter
#10  
Design specifications mostly finalized ... got it modeled in 3D so I'll be working up a cut list and start slicing and dicing later today.

Had to make some compromises on size, mostly due to me ripping off steel to use on other stuff. Width of the bottom rake is around 50" or 52", stands about 48" tall closed, with a jaw opening of around 55".

A few renderings ...

Front, upper jaw down:

Picture 12.jpg

Rear:

Picture 11.jpg

Left side:

Picture 13.jpg

Rear Perspective:


Picture 10.jpg

(It's actually designed so that the upper jaw will close another 5 degrees further than what is depicted in the renderings above.)
 

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