Backhoe Build A Backhoe For PT425... It Could Happen

MossRoad · Jul 17, 2006

J_J,
I've just been extending the cylinders by hand, being very careful to just crack the dust cap in the ports enough to let some air in and immediately closing them after reaching full extension or retraction. I'm surprised how easy they slide in and out.

J_J · Jul 17, 2006

MossRoad said:
J_J,
I've just been extending the cylinders by hand, being very careful to just crack the dust cap in the ports enough to let some air in and immediately closing them after reaching full extension or retraction. I'm surprised how easy they slide in and out.

David, Are those new or used cylinders?

MossRoad · Jul 17, 2006

New. I poured a bit of oil in each port before sliding them around. And I'm not sliding them more than a few times. Just to get the open and closed measurements.

I'm affraid I'll have to stop or slow the progress for the next two weeks. Kids have 4H projects that they need to finish up and I get to be the runner to the stores, hobby shops, etc... as well as the third hand in gluing operations.

MossRoad · Jul 18, 2006

Well, so much for waiting two weeks... the kids worked on their projects unsupervised with no problems, so I got to work on mine again.

Finished drilling the holes for the dipper stick cylinder and mounted it and the rear brackets. Tacked everything in place and tested for articulation... man, it swings smooth!

This is the 10" cylinder. I could probably go 12" or 14" without any modification, but I want to make sure that I cannot accidentally hit the backhoe pivot point or boom as J_J mentioned that someone he knew did this and damaged the boom cylinder. While my boom cylider will be on top, I still don't want to be hitting anything. I think I will use the 10" and see how it operates. If I am dissatisfied with it, I can always add a longer cylinder, or I have another choice... It is currently set for maximum lift height, which will also give it maximum depth while sacrificing the ability to dig close to the tractor. I could put another set of holes closer back towards the tractor on the dipper brackets. I could then sacrifice lift and depth for digging closer to the tractor. It would just be a matter of removing the pin and relocating the rod end to another set of holes. I think I'll leave it as is for now and only make the modificaton if I need it.

Oh, yeah, I forgot... here's some picture goodness!

Running totals:
Time = 26.5 hrs.
Approximate Cost = $380

pajoube · Jul 19, 2006

MossRoad said:
Well, so much for waiting two weeks... the kids worked on their projects unsupervised with no problems, so I got to work on mine again.

Finished drilling the holes for the dipper stick cylinder and mounted it and the rear brackets. Tacked everything in place and tested for articulation... man, it swings smooth!

This is the 10" cylinder. I could probably go 12" or 14" without any modification, but I want to make sure that I cannot accidentally hit the backhoe pivot point or boom as J_J mentioned that someone he knew did this and damaged the boom cylinder. While my boom cylider will be on top, I still don't want to be hitting anything. I think I will use the 10" and see how it operates. If I am dissatisfied with it, I can always add a longer cylinder, or I have another choice... It is currently set for maximum lift height, which will also give it maximum depth while sacrificing the ability to dig close to the tractor. I could put another set of holes closer back towards the tractor on the dipper brackets. I could then sacrifice lift and depth for digging closer to the tractor. It would just be a matter of removing the pin and relocating the rod end to another set of holes. I think I'll leave it as is for now and only make the modificaton if I need it.

Oh, yeah, I forgot... here's some picture goodness!

Running totals:
Time = 26.5 hrs.
Approximate Cost = $380

David,

Looks really good. I don't remember what you said about size bucket you will use.
PJ

MossRoad · Jul 19, 2006

I want to build a narrow one and Taylortractornut has one that I still need to contact him about. I would also like a very wide one, as our soil is all sand and will be very easy to dig large areas faster with a big bucket.

Piedmont3 · Jul 19, 2006

How are you going to attach the bucket to the end of the backhoe arm ?
The reason I ask is i have been using my mini hoe quite a bit lately, and the way the bucket is connected. I wonder about the stress you will have on the bucket connections, because of the length of the arms on your hoe. Will the connections be strong enough to handle the side to side wiggle/twist factor of the bucket if and when you try to dig something out that is maybe bigger or more solid then it looked like. I helped dig out some posts that wer concreted in and the concrete was way bigger then we thought when we started. I was afraid I was going to bend my mini hoe when we first tried to lift the concrete our of the ground. The PT just puckered and we got the bobcat to lift the concrete. But in your case with outriggers I don't think your pt will be able to pucker.

J_J · Jul 19, 2006

Jeff, Your 800 lb lifting range on the 425 , is located close to the Quick Attach points. I observed the PT pucker on my 4 ft forks with a ball on the end while trying to lift a heavy trailer off the ground. After I took off my forks, and put a ball up close to the arm connectors, I could lift the trailer with no problem. If you use the mini-hoe to lift, you lose a lot of your lifting capacity if you hook up close to the bucket including the weight of your mini-hoe.

MossRoad · Jul 19, 2006

Piedmont3 said:
How are you going to attach the bucket to the end of the backhoe arm ?
The reason I ask is i have been using my mini hoe quite a bit lately, and the way the bucket is connected. I wonder about the stress you will have on the bucket connections, because of the length of the arms on your hoe. Will the connections be strong enough to handle the side to side wiggle/twist factor of the bucket if and when you try to dig something out that is maybe bigger or more solid then it looked like. I helped dig out some posts that wer concreted in and the concrete was way bigger then we thought when we started. I was afraid I was going to bend my mini hoe when we first tried to lift the concrete our of the ground. The PT just puckered and we got the bobcat to lift the concrete. But in your case with outriggers I don't think your pt will be able to pucker.

Here's a link to where I got the plans. They are in PDF format in two files. The end of the second file details the bucket and linkage plans....

http://www.tapintothenet.net/vintagefarmplans/pbh.html

The plans call for 1/4" thick angle iron and 1" pins to hold the bucket to the end of the dipper. The linkage calls for 3/8" thick by 2" wide flat stock and 1" pins. I will proabably be using 1/2" thick flat stock instead of 3/8" and I'm not sure about the angle iron for the bucket, yet.

My guess is the hoe will lift up when I encounter an unmovable object before I break anything. It looks pretty stout. From what I have read in my research, my power for digging will be by curling the bucket, not pushing down with the dipper, so the bucket and linkage should be beefy.

I am pretty sure I will use a ring hitch and a pintel type hook on the reciever on either the front or back of the PT. If I use it on the back, I'll have less chance of puckering the PT and damaging the FEL linkage.

The author of the plans stresses that the unit is plenty powerful and can easily bounce itself around, so be careful and re-think things if it starts moving. The outriggers in the plan point straight forward. Most backhoes have them pointing out to the sides. I think mine will angle at 30 degrees instead of straight forward or straight sideways. I came to this conclusion by reading several posts on other forums regarding backhoe swing. If you use one cylinder, you can only get about 140 degrees of swing. The cylinder bumps into things past that angle. If you use two cylinders, you can get over 180 degrees of swing, but the linkage gets more complicated and there is the additional cost of another cylinder and hoses. Another thing they mention is that with one cylinder, the swing is stronger in one direction than the other. This is due to the surface area of the piston inside the cylinder being smaller on the pull than the push. They also mention that I may need to put in a flow restricter so that the swing is not too fast. Last thing they mention is to not push stuff sideways with the bucket. Loose stuff like backfill is not too bad, but hard stuff can damage the swing linkage.

So, if I have 140 degrees of swing, that's 70 degrees to each side, which leaves 30 degrees on each side for the outriggers. There should be no way that I can accidentally hit the outriggers with the bucket if I use those angles, unless I have an almost 4 foot wide bucket!

MossRoad · Jul 21, 2006

Well, I measured some things tonight. In order to get 140 degrees of swing I will need about 19-20 inches of cylinder travel with an 8" arm sticking off the side of the boom pivot box. I have those free cylinders that have 21" of travel, but they are smaller diameter than I would like. However, I could put two of them on, one on each side, and have one push while the other pulls. That may give me enough power for the swing. It will also save me the cost of a very large cylinder, and it should eliminate the problem of faster swing in one direction that I mentioned above.

So, what's everyone think about that? Does anyone see a problem with two cylinders in the same circuit, one pushing and the other pulling? From what I've read in a few other places, it should work, but I'd like some opinions.