This is the completed BACKHOE
The link to the free plans is at the bottom of this page. PLEASE read the disclaimer! I do not want to end up in court because somebody took my free plans and turned them into a new type of cruise missle.
THE GORY DETAILS
This photo is a great example of why I decided to build my own backhoe attachment.
Nearly all of the backhoe attachments I could find that would fit my Ford 8N Tractor were similar to this one. Note the back-to-back seats, and how far the lowest hinge point of the machine extends past the rear tires!
The best price I could find for something like this was $5000 (plus shipping). Several salesmen told me it would be unsafe without the added weight and expense of a front end loader. Obviously! When you look at this picture, the weight and force of the machine is carried about 3-FEET behind the rear tires! Why did they build it that way?
There are many 8N Ford tractors with front end loaders but the front axle is really not strong enough, the loaders are always very difficult to remove, and the added length would make my tractor much harder to maneuver on my property.
The local Kubota dealer has a nice small loader/backhoe that is a little more compact. But the last time I looked, the price for the small Kubota loader/backhoe machine was around $15,000, obviously way out of my price range.
Most of the better store-bought backhoe attachments are very difficult to attach and remove. They are basically permanent attachments because you have to remove the 3-point arms and use the mounts under the differential for the backhoe. That would not work for me. I did not want to turn my tractor into a single-purpose machine.
This picture shows some of the Backhoe parts when I was about half-way through fabrication and welding.
It is starting to take shape. I drew the CAD plans myself from pictures of machines I found on the web. Most of the parts are 3" square or 2"x3" rectangular steel. The plans were mainly used to figure out how many pieces of steel tubing I would need. I also stapled a copy to the wall in my shop so I could easily refer to it and keep track of changes.
My design uses a complete sub-frame that attaches at three standard 8N mounting points, two swaybar brackets under the rear axle, and a bolt through the hitch on the front bumper. These mounting points may not be quite as standard as I originally believed. Many of these tractors have aftermarket front bumpers and/or stabilizer brackets that do not exactly match the ones on my tractor. Neverless, these are still fairly standard mounting points, and this attachment will fit any N-Series Ford tractor and many others.
This is almost a stand-alone machine! All you would have to do is add an engine for the hydraulic pump and a seat. But it would not dig as well without the weight of the tractor as an anchor.
Here is the bucket nearly complete.
You can see how I welded some 2" x 1/4" steel plate around the edge for reinforcement. When I got to this point I decided to put a couple pieces of 3" angle across the back to tie the bracing together and help support the angles that the bucket will pivot on. That meant I did not need to use the plate I bought for the back of the bucket. I simply filled in the gaps with some scrap 1/16" thick material so the dirt would stay in the bucket.
The four 2" x 1/2" straps in the foreground are for the bucket pivot brackets. The way these brackets transfer motion from the cylinder to the bucket greatly increases the range of motion. Without these links the bucket would only move about 90-degrees. This was probably the hardest part of the whole project for me to figure out.
Here is a shot of the bucket and pivot brackets mounted on the end of the dipper for a test-fitting.
This was how I finalized exactly where to weld brackets and drill holes for pins. Each hinge and cylinder mounting was test-fit like this. Two of the 2" x 1/2" bucket pivot brackets mentioned previously were welded together with a hollow space in the middle to make a 2" x 1-1/8" nearly unbreakable bar that will transfer power from the cylinder to the bucket. I put a grease fitting in it so I could fill the void with grease to lubricate the pins at each end. Many small details like this were done on-the-fly and are not covered in the plans.
Here is the machine mounted on the tractor for the first time.
This is a good view of the original pivot piece where the main boom attaches to the frame. This is the piece I ended up redesigning. Note the come-a-long used in place of hydraulics.
This is one of the early side views.
At this point I still had not figured out exactly how to attach the frame to the front of the tractor. The tractor still has 15" wheels and tires on it. Yes they are 15" specials somebody made by welding 15" automobile outer rims to tractor centers. They did a nice job.
In this picture, my ground clearance under the back looks great. Everything appeared to be coming together exactly according to plan at this point.
From this shot you can see how the frame sits under the tractor and attaches to the front bumper.
I decided to remove the bottom rail of the front bumper. It was bent anyway, and that made it a lot easier to attach to the hitch tab on the front. That raised the front of the frame a bit. Then, when I put the original 19" wheels on it that raised the front of the tractor at least a couple of inches. After that I noticed I no longer had the generous ground clearance at the back, BUMMER!
This is the control station.
You won't find anything in the plans for the 2" pipe frame and control valve mounts. This kind of stuff was fabricated out of whatever I had on-hand and built to suit my personal preferance for operator comfort. This is non-load bearing and you can literally build yours any way you want. The tank is also a cop-out. I could have made one but got lazy and bought a pre-fab 10-gal tank from Northern.
Anyone familiar with these tractors should spot one modification. I made the seat swivel so I can use the same seat facing forward or backward.
Yes, the backhoe is on casters. No, it won't roll in the grass.
The casters were a real asset while I was building it, but I took them off not long after this picture was taken. Six 2" x 16" cylinders provide plenty of force for my needs but the boom and frame could probably take 3" cylinders with no trouble. I'm running the backhoe hydraulics with a $400 Prince 11-GPM PTO pump. It works great and I have discovered that by putting the Sherman transmission in low-range and running the engine at about half-throttle it is much less noisy and uses a lot less gas.
I originally intended to use the tractor hydraulic lift to raise it into position. However, after dropping and re-attaching the backhoe a couple of times, I discovered that the outriggers on the backhoe provide a much more powerful and easier way to lift the attachment into position. It is also a lot easier to insert the PTO pump if I stop short and do that before I hook up the lower lift arms. The lower lift arms just help locate the attachment front-to-back until I get the backhoe frame mounted to the swaybar links under the axle. Once those pins are in place, it is easy to attach the third mounting point to the front bumper.
The backhoe attachment is a little more difficult to attach and remove than my bush hog, mostly because of the additional weight. This backhoe attachment weighs about 1000 pounds, so you have to figure it is going to be harder to deal with than most implements. But I'm really happy with the results. The worst case scenario so far is trying to attach the backhoe on a less than level area. I had to go get a hammer to give the pins a few whacks, and it still only took me about 10 minutes!
DESIGN FLAWS
Sometimes I even amaze myself. I am 100% satisfied with the way this project has turned out. However, in any project like this, there are usually a few do-overs. Sometimes you have to break it to find them.
1 - Several of my 7/8" pins started to bend. I straightened them on my shop press, but that was only a temporary fix. The pin-and-clip arrangement I used leaves too much slop in the joints for good strength. All of the hinge pins have now been replaced with a pipe sleeve (used as a bearing). The sleeves are captured in each joint with a bolt through the middle with big washers on both sides.
UPDATE AUG 2007 Apparently even that aint good enough. Here is a picture of one of my NEW pins at the bucket. 
Looks like at least this one is going to need a larger/stronger bolt.
2 - The main hinge point where the boom attaches to the frams was too weak. It worked, but was obviously under-designed. I redesigned it and the new one also gets back some of the ground clearance I lost earlier.
3 - Learned a new technique but broke it again. The easiest and fastest way to push dirt into a hole is to use the side of the bucket and sweep dirt sidways. I was quite proud until I tore the mount for the cylinder running the side-to-side motion right off the frame. This mount was a piece of 1/4" thick steel angle but the cylinder tore one flange in half like it was a piece of cheap cardboard. Oops! I did not anticipate doing any real work with the side-to-side motion. I straightened the bracket, welded it back together, and reinforced it so that won't happen again.
4 - Running the side-to-side motion with only one cylinder works, but it is a little awkward. Hydraulic cylinders take more fluid and have more force when extending than retracting. This means the boom moves much faster to the left than to the right and it is hard to get used to. The difference in speed and force is mot nearly as obvious with any of the other up-down or in-out motions of the boom, dipper, and bucket.
5 - Each outrigger is attached to the frame by a hinge made with two pieces of 3" angle iron welded to the frame. It looked simple and strong. They are plenty strong enough to raise the rear tires off the ground. But not strong enough to resist the forward and backward force of digging with the backhoe. I have pulled them both loose from the frame and had to weld them back on.
Here is a photo of the new hinge piece.
The new hinge piece restored most of the ground clearance that I lost in the back. Moving the boom hinge point higher also made it easier to pick up and carry things like stumps with the bucket and boom.
I set the old part next to it for comparison. As you can see the new one is much larger and stronger. How about those Ford decals for an original equipmnent look!
Close-up of the new hinge piece.
This shows the additional bracket for a second cylinder to run the left-right movement. This will be a future upgrade to smooth out the left-right movement.
Close-up photo of the bucket and brackets.
Recent photo (MAR 2007) with backhoe on my 52-8N tractor.
TOTAL COST - Assuming you have to by all New Steel, Hydraulic Pump, Cylinders, Hoses, Control Valves, Tank, Fittings, Hardware, Welding Rods, Primer, and Paint - Less than $3000. If you have access to salvage parts and scrap steel, your price will be much less.
Design Time and Shop Time - About 12 Weekends, Priceless.
SEAT SWIVEL
I cut the seat bracket. You can see where I welded two pieces of 1/4" plate to extend the bracket so it would overlap the bottom piece. Drilling a hole for the bolt was no fun at all! This bracket is spring steel, and very hard to drill. I put a big fender washer and a dab of grease between the brackets for a pivot point.
I planned to make a latch to lock the seat facing forward or backward, but changed my mind after using it this way. The bolt is tight enough to provide some resistance and the swivel feature makes it much easier to get on and off the tractor!
NEW JOYSTICK CONTROLS!
I wanted these, but left them out of the original design because they were expensive and I wanted to make sure the project was successful before spending the extra money. Each joystick combines two motions in one control so it is much more intuitive and easier to operate with two hands. The left hand joystick controls the side-to-side and up-down motion of the main boom. The right hand joystick controls the dipper and the bucket. Moving either joystick diagonally gives you two motions at the same time. The two controls in the middle operate the outriggers.
BACKHOE AT WORK
Here are some recent photos of my backhoe at work.
The first photo is at 12:09 PM getting ready to go get the attachment.
This photo is at 12:21 PM with the backhoe attached and ready to work.
This photo is at 12:50 after digging two deck foundations 30" deep.
This is exactly what I wanted to be able to do with it. I did not want to end up with a single-purpose tractor. This implement is not incredibly difficult to attach and I was able to do this small job in less than an hour from start to finish even with time out to take pictures.
BACKHOE PLANS:
The link below will get you a PDF copy of the plans I created for this backhoe. Of course, I made a few modifications during assembly. The primary purpose of these plans was to work out sizes of the major components and figure out what I would need in the way of materials.
Items that are not dimensioned were cut to fit on the tractor. Mounting points for the cylinders were determined after assembly of the major components. I did it this way to make sure I had more travel in the joint than in the cylinder. You usually want your cylinders to run out of travel first. If not, they will be trying to pull or push the machine apart. If possible, I also wanted to have all my cylinders be identical. That way I would only have to buy one spare to replace any cylinder that might get damaged.
DISCLAIMER:
Here is a link to the drawing I created and used to build my backhoe. It has been updated with new information for all the pieces I broke and re-designed so you will already have the benefit of my initial prototype testing (breakage). This is freely distributed information without any guarantee of any kind. By clicking this link you are agreeing to not hold me responsible for any problems, damages, injury or death that may occur from the actual use of this information. If you do choose to tackle a project like this, be very careful! Make sure your welds are good and strong! These are very heavy parts, and the machine will generate a lot of force that could easily bruise, crush, sprain, squash, mangle, traumatize, cut, rip, tear, amputate, kill, etc. I'm not joking! This is meant to discourage anyone who has not previously attempted similar projects.
Click Here To get the 8N Backhoe Plans
NEW! Click Here To get the 8N Backhoe Bill of Materials
NEW! Click Here To leave this site and go to... KPX Tractors
KPX Tractors manufactures an interesting backhoe attachment and wood chipper.
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