Compact Tractor Grapple Build

[fasttruck860]

In April I started designing my own grapple due to lead times, cost and my own curiosity. I needed a good tractor project under my belt to go with my first tractor. The first thread here focused on some build questions I had and honestly had a lot of good discussion. Part of my driver for building the grapple was the fact that a friend of a friend was going to get me the steel cnc plasma cut for free. I do have a plasma cutter but the templating, grinding and sanding would have taken way more time than I cared to spend on it. There was a catch to the free part, it only pertained to steel they stocked in their shop. I wanted AR400 so I had to pay their cost for it which was about $600 for a sheet of 3/8" plate. Not bad, but to make sure I wasn't spending too much on the parts I elected to use only AR400 on the tines and some of the other smaller bits to fill out the sheet. The gusset teeth, protection plates and the pieces I fabbed in my shop are all hot rolled steel.

As I mentioned I designed this grapple in autocad which based heavily on the EA wicked grapple. I did have to come up with my own dimensions and geometry which was based on other grapple cut sheets I was able to find online. There were some parts and pieces I ended up just leaving out, such as, the cylinder brackets because I just wasn't sure what I was going to use yet. Since I'm now almost finished with the project I thought I'd share the build and some of the things I learned along the way.

The majority of the grapple was built out of 3/8" plate (tines, hinge brackets and cylinder brackets). The tube steel was all 1/4" wall as was the DOM tubing. The gusset teeth, protection plates and some of the additional items were 1/4" plate.

This is the pile of parts from the fab shop. All the rusted pieces are AR plate.

Initial layout of the lower tines-

Fit up and tack welding the lower tines. I spent a lot of time making sure these were as aligned as I could make them. I had an issue with one tine which seemed to be slightly warped. I choose to have the end tines cap the tube steel for strength and they are a slightly thicker depth than the "inner" tines which creates a different geometry.

The first fitment issue was adding the 1-1/4" rod at the lower teeth. The one tine that wasn't sitting flat was in the middle and it made it really difficult to slide the rod through. If I were to do this again I'd slightly oversize the plasma holes due to the bevel that the cutting tends to create.

The last part of the lower tine work on was the gusset teeth. I ended up cutting the back section off each one, grinding a slot, bending and welding each one back together to get the right offset I was looking for. The first two ended up being different because I wasn't exactly sure what was going to work best here.

 

[fasttruck860]

Some additional details on the gussets. I elected the grind a slot in the front of each one, weld it and grind smooth for added strength. Despite the plug welds I was worried that eventually something would wedge in there and bend one of the teeth. I had to grind one side of the weld at the bend to make the teeth sit flat against the tine in the front.

Here's the lower section welded up and ready fit the upper lid and hinge brackets. Just about every weld on this build was full length and double sided, except some items that I didn't think needed it.

Here's one of the parts I elected to fabricate myself that really took a bunch of time. I know you can buy the SSQA, but they're typically a full plate section and I wanted to keep the grapple as light as possible while still being really stout. I spent a lot of time measuring my fork carriage and test fitting this part of the build to get it just right. I ended having to grind a lot of the welds to make sure the attachment plates sat really flat against the grapple.

 

[Smokeydog]

That’s a great project! Nice fabrication skills!Very envious! Don’t think you are saving much on cost or lead time but I think that was never the point. Making something in a way that you cannot buy. Priceless.

Absolutely love the wicked grapple on the Kubota B26. Home run on the design. They did notch in some horizontal square bars on the back to help prevent sticks from reaching the tractor. I also improved the grill guard too. Necessary with any grapple.

Curious how structurally the AR400 holds up. Always a comprise of abrasion resistance, strength, ductility (flexibility), cutting and welding challenges. You probably know lots more than I. I know enough to realize my ignorance on most things.

Do like how the tine tips touch on the wicked. Can pick up the smallest branch or rock particularly with the agility of the smaller tractor. The bigger tractor uses a skidsteer heavy grapple with bypass T1, 1/2” tines. Advantages of that type too for pulling brush. Both grapples are long bottom, dual lid type.

You have something to be very proud of. Looking forward to seeing your progress.

 

[Smokeydog]

See you haven’t boxed the sides of your ssqa. Added angle wings or lips on some of mine to help alignment. Set some of my attachments out of the weather under low buildings with uneven floors in relation to tractor. Big tractor has lower visibility.

 

[fasttruck860]

That’s a great project! Nice fabrication skills!Very envious! Don’t think you are saving much on cost or lead time but I think that was never the point. Making something in a way that you cannot buy. Priceless.

Absolutely love the wicked grapple on the Kubota B26. Home run on the design. They did notch in some horizontal square bars on the back to help prevent sticks from reaching the tractor. I also improved the grill guard too. Necessary with any grapple.

Curious how structurally the AR400 holds up. Always a comprise of abrasion resistance, strength, ductility (flexibility), cutting and welding challenges. You probably know lots more than I. I know enough to realize my ignorance on most things.

Do like how the tine tips touch on the wicked. Can pick up the smallest branch or rock particularly with the agility of the smaller tractor. The bigger tractor uses a skidsteer heavy grapple with bypass T1, 1/2” tines. Advantages of that type too for pulling brush. Both grapples are long bottom, dual lid type.

You have something to be very proud of. Looking forward to seeing your progress.

In the end I think the project will cost me about half what a new grapple would cost. I'm in it for about $1300 at this point and I just bought the last item which was paint. On the time you're definitely correct with it being 13 weeks since I decided on building vs. buying. Once I get to cleaning and painting it will most likely be right around 15 weeks.

 

[fasttruck860]

See you haven’t boxed the sides of your ssqa. Added angle wings or lips on some of mine to help alignment. Set some of my attachments out of the weather under low buildings with uneven floors in relation to tractor. Big tractor has lower visibility.

The next update will have the full boxing of the ssqa and the tine tips alignment. I didn't take pictures everyday since I'm usually in a rush and sometimes I start working on something different based on time to fabricate vs. what I have on hand to build with.

 

[Xfaxman]

 

[fasttruck860]

Now we get to the part that really took me the most time on the project, the upper tines. This part of the project was really about 2/3 of my total time building this attachment. It wasn't that it was difficult but I checked and recheck to make sure parts were square and aligned properly. I didn't do myself any favors by electing to use a 30" long 4140HT pin for the hinge point. I designed the hinge brackets to accommodate a 1" pin and the upper tines where cut out to accept the full 1-1/2" OD of the DOM tubing. My biggest initial issue was that the 1" pin didn't quite fit in the 1" OD of the tubing. Each had a tolerance of about .005" and somewhere it was off enough to cause an issue. Since I didn't have a lathe I decided to use a 220 grit sanding disc. It took me about an hour to get just the right fit without any binding. I do plan on polishing the pin again before it all goes back together.

I talked about the beveled edge that sometimes can be created with the cnc plasma cuts. The holes cut in the hinge brackets had this bevel and some blowout from the piercing cut on the machine. What I ended up doing was using my hand held router with a carbide burr to take out the beveled edge. Now the holes were perpendicular to the adjacent plate surface.

After

Next step was to drill and tap the tubing to accept the zerk fittings. I did make a mistake here that wasn't realized until the very end of the build.

As Smokeydog pointed out the nice part of the wicked grapple is that the tines align in the front which is what I was going for. The fact that the tubing inserted into the upper tines really helped in this step. There was only two surfaces that needed to align, the tube and the hinge brackets. What I ended up doing was setting the tines back one tooth and getting them square and gapped for paint (using wire), tacked the tubing and the brackets. I eventually slid the whole section forward and hammered the pin in to check for alignment and function.

After I know everything was correct I install the tube steel bracing that will connect the cylinder from upper to lower.

 

[Smokeydog]

Amazing work. Great build.

Sometimes a long pin or bushings have a grease channel to help distribute and hold some lubricant.

What is your target weight?

 

[fasttruck860]

Thanks for the kind words. I still make mistakes along the way but I just make less of them as I get older.

The channel isn't a bad idea I'm going to have to look into that.

I was shooting for #350 and I think I'm pretty close to that weight, I don't think it's #400. The bottom tines I can actually move off the bench onto the ground one end at a time. The upper tines surprised me with how heavy they got despite only having four.

I wanted a beefier setup because I have the feeling that after this tractor is paid off I'm going to want something larger, the next size up