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Discussion Starter #1
My 260B is okay for digging holes and ditches, but I don't like it that much. I feel like its too heavy, almost like they scaled a 310C and called it a day. When you look at the cross-sectional area of a orange backhoe, its a fraction of the JD backhoe, so one of the two missed the mark. To preempt it.. I don't want to own, and prefer not to rent a mini-ex. My end goal is to increase the BH's lifting capacity, ideally by double (rockeries). I think most of this can be achieved by geometry, as an example, putting the cylinder under the boom pin now means it is lifting the boom with the full area, rather than only the rod area in the current config, the downside is this reduces the digging force capability.

1. Why are backhoes often a straight boom, or slight curve vs a mini-ex which has a banana boom? I suspect the common use case is digging ditches, which that config is fine for.
2. If you were to mush a mini-ex with a backhoe, what features would you adopt from the mini ex, which would you leave out?

The attached picture is a comparison of the 260B and a Case CX17C kinematic model I built.
260B has a stored height of 5.3' and 2.75' tail hanging out from the kingpin, the cx17c stored similarly is 8.2' tall and 3.2' aft of the king pin.

If i stare at this too long this winter, the welder might come out ha ha.

Note: The biggest limitation I see so far is that a 1.25" rod is getting to be a bit on the slow side due to the 1025R's low hydraulic flow. the CX17C I was comparing above has a 13 gpm flow.
 

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You can't really compare the two.
The 260 is a roughly $5000 attachment on an already small pumped homeowner utility tractor.
The mini excavator is a commercial $25K ish hoe designed to dig. Everything supports the hoe.

Boom lift cylinders on backhoes are generally designed to allow them to be useful yet be able to retract fully to fold up the backhoe as compact as possible. You are trying to lift things on the back stroke, or retraction, of the boom cylinder.

The 260 is just a scaled down version of the design of almost, if not all, of the modern major player combination backhoes out there by Deere, Cat, Case, JCB, etc.
 

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If you want to do more than what a 1025r can do the pony up the bucks for a bigger tractor or mini ex.It can only do so much with cylinder size and hydro pump.Changing the configuration isn't going to change anything pump and cylinder size will,but then you exceed what the steel can handle.The reason some booms are curved like Cat for example is to dig close to the hole near the unit so it doesn't hit the edge of the bank.
One feature I like on backhoes and we have at work on our New Holland and Bobcat mini is the extend on the boom.Comes in handy quite a bit.
 

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My 260B is okay for digging holes and ditches, but I don't like it that much. I feel like its too heavy, almost like they scaled a 310C and called it a day. When you look at the cross-sectional area of a orange backhoe, its a fraction of the JD backhoe, so one of the two missed the mark. To preempt it.. I don't want to own, and prefer not to rent a mini-ex. My end goal is to increase the BH's lifting capacity, ideally by double (rockeries). I think most of this can be achieved by geometry, as an example, putting the cylinder under the boom pin now means it is lifting the boom with the full area, rather than only the rod area in the current config, the downside is this reduces the digging force capability.

1. Why are backhoes often a straight boom, or slight curve vs a mini-ex which has a banana boom? I suspect the common use case is digging ditches, which that config is fine for.
2. If you were to mush a mini-ex with a backhoe, what features would you adopt from the mini ex, which would you leave out?

The attached picture is a comparison of the 260B and a Case CX17C kinematic model I built.
260B has a stored height of 5.3' and 2.75' tail hanging out from the kingpin, the cx17c stored similarly is 8.2' tall and 3.2' aft of the king pin.

If i stare at this too long this winter, the welder might come out ha ha.

Note: The biggest limitation I see so far is that a 1.25" rod is getting to be a bit on the slow side due to the 1025R's low hydraulic flow. the CX17C I was comparing above has a 13 gpm flow.
I have both a Case CX17C and a 260 Deere backhoe. If you need any other measurements, etc I'd be happy to help.

You can see some 'comparison discussion' on recent videos on our channel. Link in my signature.

These are really apples and oranges. I like them both.

Tim
 

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Discussion Starter #5
Hey Tim, I really appreciate that! My biggest hangup so far for the Case is getting rod & piston diameters. Is it possible to get those measurements for me? For the 260B, i measured the rod with a caliper, then used JD PartsAdvisor to get a picture of the blown up assembly. I could then scale the measurements in the picture to that of my known rod diameter. I could not find an equivalent to JD's partsadvisor for case, but worst come to worst, given the OD of the rod and cylinder, i can make some guesses.
At some point (once this becomes serious!) I might pester ya for detailed pictures or a video of the fittings & reinforcements, but we're not there yet). :bigthumb:

The plan so far:
> Develop kinimatic model of 260B & CX17C (Done except 4bar mechanism on the bucket, todo this week)
> Develop Internal Loads model of the system (forces & moments for a given applied load)
> Develop Hydraulics model (actuation times, forces, etc)
> Compare against published breakout forces (am i close?)
> Smoosh the two models into a customized hybrid model & tinker until height, times, lift capability, and digging capability are at a happy nexus... 260X is Born.
> Detail Design(spring time..?)
> Build next winter (this will go on hold for summer projects)

for the curious, the scaled numbers i came up with are:
Boom: Piston Dia = 1.85", Rod Dia = 1"
Dipper/Arm: Piston Dia = 2.38", Rod Dia = 1.25"
Bucket: Piston Dia = 1.81", Rod Dia = 1"

I suspect the Bucket & Boom are both the same diameter piston, but will leave it be for now until I compare to published breakouts. The attached image was how i scaled... copy a picture into powerpoint, draw two parallel lines to the Iso view, draw a right angle triangle that is parallel to the lower line, extend it to it touches the upper line.
 

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Hey Tim, I really appreciate that! My biggest hangup so far for the Case is getting rod & piston diameters. Is it possible to get those measurements for me? For the 260B, i measured the rod with a caliper, then used JD PartsAdvisor to get a picture of the blown up assembly. I could then scale the measurements in the picture to that of my known rod diameter. I could not find an equivalent to JD's partsadvisor for case...
Here is the trick I found for finding the parts breakdown. I believe the New Holland E17C is essentially the same machine as the Case CX17C. So, use this link, and search for E17C

https://partstore.construction.newholland.com


I can still measure rod and cylinder diameters if you need it. I don't have calipers, so it would be likely be less accurate than you are seeking.
 

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Discussion Starter #7
I will need the measurements to scale from. Lets see how they look... if its horrible, pm me your address & santa will drop some calipers in the mail! :D
 

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I will need the measurements to scale from. Lets see how they look... if its horrible, pm me your address & santa will drop some calipers in the mail! :D
Bucket curl rod is 1 3/8" Relatively confident in that one. I used an adjustable wrench like a caliper, then measured the opening in the wrench.

Adjustable wasn't big enough for the Dipper and boom cylinder rods. They are the same diameter, I believe 1 5/8", but I can't be sure.

The outer diameter of the tube for each cylinder is more difficult for me to measure. I guess I'll have to get some calipers

Tim
 
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