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

 

[Smokeydog]

You have the beef for sure.

You going to put plates between the top tines?

 

[fasttruck860]

You have the beef for sure.

You going to put plates between the top tines?

That was my next step. Surprisingly these things are sharp and hell on the hands trying to manually operate the lid. I did make a small mistake here since I was using a smaller dowel to hold the hinge point in place after I took out the 1" hinge pin. The tooth alignment left to right shifted slightly and I didn't realize it until later.

Here's the other mistake I mentioned in previous post. The left two upper tines and the right two upper tines are held together with the DOM tubing to create the hinge point. The center being stationary has a section of tube welded between two of the hinge brackets. I drilled and tapped a grease fitting right in the middle because that's what I did for all of them. For that section it puts it right in the middle of the upper cylinder mount and the cylinder. To fix this I ordered a 90 degree zerk fitting. I'm hoping this works because otherwise I'm going to have to drill and tap this in a new location while being welded in place.

Here's the upper cylinder mount with gussets added. I still have a lot of clean up on this part left to complete which will be this weekend. The cylinder brackets are definitely something I could have drawn in CAD and had them cnc cut, but I wasn't exactly sure the best way to mount it. I also wanted to make sure I had enough of an elevation change between the upper and lower mount so the cylinder would have some advantage as it extends. I ended up with 5" of height differential between the two mounting points. The bad part about this design is that I'll have to pull the pins to lube the pivot points.

After testing the clearance of the cylinder multiple times I finally settled on the location of the protection plates. I ended using a 2.5"x6" stroke cylinder.

Not a whole lot left at this point. I'll spend sometime this weekend grinding, sanding, checking for missed welds and then wash the whole thing down with acid to prep for painting. I might add some steel flat stock in the middle to protect from branches that might come through the middle towards the tractor.

 

[Xfaxman]

. What is the open measurement?

 

[Smokeydog]

I move lots for brush, trees and roots. Those plates between the tines do lot of the grabbing. Also handy for setting crosstie fence posts.

That big of a weldment is not easy to fabricate. Challenges of design many. Building a one-off takes crazy time and ingenuity. Remarkable the many skills you have.

Grapples stay on the tractors more than any other implements. Been a game changer. I’m sure you will find it super useful.

Is anyone fabricating grapples from AR400? Your selection of material over T1, xx60, xx80 steel?

 

[fasttruck860]

View attachment 706693. What is the open measurement?

Measures right at 37" tooth to tooth.

I move lots for brush, trees and roots. Those plates between the tines do lot of the grabbing. Also handy for setting crosstie fence posts.

That big of a weldment is not easy to fabricate. Challenges of design many. Building a one-off takes crazy time and ingenuity. Remarkable the many skills you have.

Grapples stay on the tractors more than any other implements. Been a game changer. I’m sure you will find it super useful.

Is anyone fabricating grapples from AR400? Your selection of material over T1, xx60, xx80 steel?

You're not the first person to tell me the grapple will always be on my tractor. I'm really looking forward to cleaning up my woods and creating some trails for the kids.

I've seen a few companies use AR400, but also some of the cheaper ones just using A36. I guess A572 Gr50 would have been a good option. I think most shy away from the AR plate because of the welding procedure. I didn't follow the procedure to a T on every weld, but I did use the correct wire, delayed the cool down period, no overly restrained fitments and I also didn't sink a ton of heat into the metal.

 

[suncoast]

Nice weld table. I used casters on one I built also. Yours is more stout than mine Good job

 

[fasttruck860]

Nice weld table. I used casters on one I built also. Yours is more stout than mine Good job

Thanks, it's simple and was fairly cheap to build plus my shop is small so everything has to be mobile or up against a wall. After moving the grapple around on it I'm going to add some additional bracing to keep the legs steady. I intend on making some holders for my grinders and the little things that keep falling off the top.

 

[Smokeydog]

Clever trick using a router to square up plasma cut holes. Used die grinder with burr many times. Have to remember that one.

 

[Smokeydog]

Cross tube mounted cylinders are easy to drill and tap for grease fitting but requires two brackets on each end.

Might find a loader pins with end grease fittings that work?

Option of making pins or drilling bracket mounts.

That crimp force geometry and cylinder selection is what the high end grapples manufacturers have figured out better.

 

[fasttruck860]

I think I'm going to drill the pins and put a fitting in the end. This should be serviceable and easy enough to do.