Completely homemade excavator

[snowb]

VERY COOL! This is very ambitious and you seem to be chugging along, this gives me some guilt about letting my own larger projects grow stagnant. You inspire me. Thank you for sharing.


I am curious about your hydraulic system design. By my rough estimate, 19GPM @ 3,000PSI would require at least 40HP. Since you're using a 15hp engine I assume you are using 19GPM at lower pressure (for fast transit) OR 3,000PSI for digging/pushing, but not both at the same time. In my experience this kind of arrangement is addressed with load sensing valves that control the displacement (swashplate angle) of the pump. These systems get pretty complicated pretty quickly. I have pondered simpler ways to do it, and I'm curious if you've found one of these simpler ways, or if you're using load sensing. Actually I'm just curious in general, about all of it, mostly the hydraulics.

Thanks,

For example a KX71 excavator has a total hydraulic flow of 35GPM with a 27HP motor but does not use all at the same time at maximum force. As for shoveling it uses only 5 GPM, the engine runs in neutral, despite everything the operator does not have the choice to increase the engine speed to have a good shoveling speed.


On my excavator I have an adjustable valve to divert a percentage of the flow rate of 12.7GPM directly to the tank without pressure build-up. I would have all the flow I wanted in shoveling mode without increasing the engine speed, because 5GPM / 3000PSI does not require a lot of power (9HP is sufficient, it is not 3000psi continuously)
I have used this system on my 2 previous excavators and it is wonderful to be able to adjust the speed beyond the engine speed.
The 6.3 GPM auxiliary will be used to give an acceleration of 2km / h no matter what percentage of flow the 12.7 will be adjusted. To use 19gpm at 6 km / h I would not need 3000PSI to move on normal terrain without pushing sand with the blade. If I need to push the 6.3 will not be activated.
My experience with diesel engine pumps has shown me that we can use a flow 30% higher than the rule of 3GPM for 6.5HP, if the pump does not work continuously close to 3000PSI.

 

[snowb]

Snowb,
Awesome project. Are the trailer wheels and tires gonna be your idler wheel at the tensioner? Also, can you show more photos and information on your Kubota crawler lift? That little thing looks awesome.
hugs, Brandi

Thanks,

the dozer snowblower blade rear lift bucket https://www.mytractorforum.com/threads/mini-dozer.738865/


Yes they a trailer hub with shortess possible axe. The wheel is a plain steel disc for correctly guide the track in the central groove

 

[bindian]

Which is pretty much what itç—´ supposed to do. Is lifting the rear 1/4 inch vs 2 feet any different?

The biggest and most damaging thing is the center of gravity of the machine shifts. The more it is lifted at the rear, the more the center of gravity (and mass of weight) moves forward. Get center of gravity (CG) too far forward and components and parts are subject to forces they are not designed to withstand and they become overstressed.

Not so stubble is seals on tensioners can blow and you throw a track.

Stubble, like the CG moving forward, is balanced weight on the turntable moving to one side and prematurely wearing out turntable bearings. It all adds up to $$$$ for repairs. It does matter, if you are paying the bills.
Brandi

 

[LD1]

The biggest and most damaging thing is the center of gravity of the machine shifts. The more it is lifted at the rear, the more the center of gravity (and mass of weight) moves forward. Get center of gravity (CG) too far forward and components and parts are subject to forces they are not designed to withstand and they become overstressed.

Not so stubble is seals on tensioners can blow and you throw a track.

Stubble, like the CG moving forward, is balanced weight on the turntable moving to one side and prematurely wearing out turntable bearings. It all adds up to $$$$ for repairs. It does matter, if you are paying the bills.
Brandi

I wouldn't exactly call what he did, for a picture, as abuse.

IF that is done every time, and allowed to slam back down from several feet...sure.

But the machines are built to handle this. Id really hate to see you on one being paid hourly

 

[4570Man]

I wouldn't exactly call what he did, for a picture, as abuse.

IF that is done every time, and allowed to slam back down from several feet...sure.

But the machines are built to handle this. Id really hate to see you on one being paid hourly

You’re right that letting it drop and slam back down is by far the hardest thing about doing that which I’m pretty careful not to do. Lifting it the first 1/4” is the hardest part. It gets easier to lift the higher it goes. And the blade has like a 4” or 5” cylinder that’s pretty much a straight push without mechanical loss. It’s not working very hard to hold the whole machine.

 

[bindian]

I wouldn't exactly call what he did, for a picture, as abuse.

IF that is done every time, and allowed to slam back down from several feet...sure.

But the machines are built to handle this. Id really hate to see you on one being paid hourly

Yeah, there always a chance there might be damage you haven't seen and doing stuff like raising the rear end on purpose just might snap that unseen damage.
If someone was paying me hourly to run one, I wouldn't be raising the rear end a foot or so off the ground. But I would be pushing the machine to it's limits. Then again.................I wouldn't be paying the $$$$ repairs either.
hugs, Brandi

 

[4570Man]

The hydraulic limitation of the machine was reached at the point the tracks lifted at all. Pulling it more at least until the oil starvation point which is a lot more than a foot high doesn’t cause any more stress.

 

[bindian]

This excavator is only 2400lbs and has a reach of approximately 12 feet from the front axles. There is still a way to work without overturning, even if it is not the heaviest in relation to its reach, in addition the ground is super soft there, it only holds by the grass.

So you built this "Caterpillar" also? Simply amazing
hugs, Brandi

 

[bindian]

Thanks,

the dozer snowblower blade rear lift bucket https://www.mytractorforum.com/threads/mini-dozer.738865/


Yes they a trailer hub with shortess possible axe. The wheel is a plain steel disc for correctly guide the track in the central groove

This build is awesome also. To bad photo bucket puts those banners on the photos. They make it hard to focus and see the detail well.
hugs, Brandi

 

[snowb]

The casings which pass through the center of rotation all have a live swivle so that they do not twist on themselves with each rotation, of course the rotation is limited to 420degree so as not to do everything on itself which would cause a kink between the guts. There was very little space to put the pipes and 8 rotating joints in the center, no room to put 1 more. Protection plate below.

Difficult to make equipment of this size in this garage, impossible to turn the frame with arms to check the movement of the pipes.

 

[snowb]

My only used part, the engine, I had tested it on the floor 2 years ago after buying it, after an adjustment it seemed to work very well.
So after having all installed the hydraulic circuits and the main electrical circuit. I started the engine (after a purge to remove the air from the circuit) the engine started on 1 cylinder with little power. The other cylinder does not see diesel. No instructions for this pump on the internet, the motor manual does not cover pump assembly. So I deduced how it works by looking at different mechanical injection pumps. But nothing seems to work the way it should, only injects at a precise 360 degree position, so no engine revs can be adjusted. Until I realize he has a slit in the pump body.
Having spent all this time making the motor and pump mounts, everything configured accordingly, everything cleaned, fabricated the hanger and baffle for the radiator, make the electrical system accordingly.
Option of another used diesel engine + $ 900, they loaned 4000hours, not sure if they were serviced.
New diesel yanmar engine, same model = 9500CDN ...
New injection pump = 2600CDN without installation and adjustment instructions, the rest of the engine is not new and may give other surprises. and not avilable fast.
New gasoline engine option which is usually my first option, I opted for a Honda 2 cylinder with 20 amp generator. I shouldn't be any surprise with this one and I know these tuners with affordable parts well. All that remains is to redo the motor support, pump supports and add steel plates to compensate for the reduced weight of the gasoline engine.
At $ 2100 for the engine guaranteed for 3 years it is less expensive than just the diesel engine pump. Even worse, I had just sold a used but extremely cleanHonda GX690 engine (which had been in my inventory for a few years) for a fraction of the price, he should have gone into the excavator first ...

 

[snowb]

The hydraulic hoses are not exposed to the outside of the articulation like most excavators, they pass inside very close to the points of rotation in order to reduce to the maximum the lengthening and the narrowing of the course of the hoses when the articulations move.



First hydraulic system tests, movements, leak checks. Carried out with the electric starter. Surprisingly, in addition to having to fight engine compression, it generates enough hydraulic pressure to lift the excavator. After all these tests I had to recharge the battery, ran out of energy to back the excavator back into the garage.
The movements of the arms, which have been previously calculated by hand on paper with a compass and a ruler, are complete from end to end. The first boom rises almost to the roof of the excavator. The hydraulic thumb is practically embedded in the arm when raised.
The pins (1 ’’ grade bolts, 1.25 ’’ for the base joint) are all snug in their holes, no play, straight. After each ring was welded, I adjusted the inside diameter with a manual adjustable reamer, big job.
Several hydraulic controls required the manufacture of special Ting fits to place them next to the seat, otherwise there really would not have been space to put standard hoses and fittings between each component.
Out of about thirty welded hydraulic connections, only one showed a slight leak, I cross my fingers.


Tilt left-right grader blade (not normally available on a commercial excavator) In addition to being useful for leveling, the tilt will provide better stability for shoveling when the excavator is not on level ground. The challenge was to find a way to fit everything within the height of the scraper of just 11 inches, otherwise it would have prevented the excavator from rotating. In addition to having a sufficient angle of rotation but not too much so that the speed of rotation does not make it too difficult to adjust.
Removable extensions to widen the blade.

 

[snowb]

So you built this "Caterpillar" also? Simply amazing
hugs, Brandi

Thanks, fabricated in 2015

BRX8, Motoneige, Vtt, vehicule tout terrain,artisanale,fibre de carbone,moto hors route, Snowmobile, ATV, all-terrain vehicle,craft,carbon fiber,off-road motorcycle,excavatrice,excavator,home-made,small-doo,Ski-Doo,Tundra, mini dozer, dynamometer,trailer,remorque forestiere, fendeuse ea bois, log splitter

 

[bindian]

There was very little space to put the pipes and 8 rotating joints in the center, no room to put 1 more.

Snowb,
My excavator has 4 lines to the drive motors. Add 2 more for your blade. What are the extra 2 rotating joints for?
Airline mechanics call those rotating joints, "banjo fittings". Every leading edge slat has two. But they are way more compact then yours, as they usually come off of 1/4 inch lines.
Edit.............now I see why.................a tilting blade. AWESOME.
hugs, Brandi

 

[bindian]

The first boom rises almost to the roof of the excavator. .

Snowb,
That is called the boom. The part of the arm near the bucket is called the stick.
hugs, Brandi

 

[bindian]

My only used part, the engine, I had tested it on the floor 2 years ago after buying it, after an adjustment it seemed to work very well.
So after having all installed the hydraulic circuits and the main electrical circuit. I started the engine (after a purge to remove the air from the circuit) the engine started on 1 cylinder with little power. The other cylinder does not see diesel. No instructions for this pump on the internet, the motor manual does not cover pump assembly. So I deduced how it works by looking at different mechanical injection pumps. But nothing seems to work the way it should, only injects at a precise 360 degree position, so no engine revs can be adjusted. Until I realize he has a slit in the pump body.
Having spent all this time making the motor and pump mounts, everything configured accordingly, everything cleaned, fabricated the hanger and baffle for the radiator, make the electrical system accordingly.
Option of another used diesel engine + $ 900, they loaned 4000hours, not sure if they were serviced.
New diesel yanmar engine, same model = 9500CDN ...
New injection pump = 2600CDN without installation and adjustment instructions, the rest of the engine is not new and may give other surprises. and not avilable fast.
New gasoline engine option which is usually my first option, I opted for a Honda 2 cylinder with 20 amp generator. I shouldn't be any surprise with this one and I know these tuners with affordable parts well. All that remains is to redo the motor support, pump supports and add steel plates to compensate for the reduced weight of the gasoline engine.
At $ 2100 for the engine guaranteed for 3 years it is less expensive than just the diesel engine pump. Even worse, I had just sold a used but extremely cleanHonda GX690 engine (which had been in my inventory for a few years) for a fraction of the price, he should have gone into the excavator first ...

That is truly disheartening news. Especially selling an engine you could use now. Surely with your skills, you can repair a slit in the pump body. How about a used injector pump?
hugs, Brandi

 

[snowb]

Thanks,
Since time is limited to 24 hours a day, I have other projects to complete before the snow falls and cannot do them when the excavator is in the garage, so I go for the new engine.
Of course, since the engine is completely different, I had to make engine mounts, install steel plates to compensate for the weight of the engine (and even more), make a 2 in 1 exhaust.
Make supports for the 2 pumps, different configuration problems! Relocation of the oil tank. There is 0.25 '' of clearance (top, bottom, left right) from the 2nd pump drive.
Redo part of the electrical wiring and buttons (not the same controls) Redo the throttle and choke controls, etc.
While a repair to the diesel engines would have been of very uncertain duration, even if the leak was fixed. I suspect other malfunctions in the pump. I haven't found a used injection pump anywhere on the net.

The new Honda engine will be reliable for a long time, not as long as a new diesel engine, but more than an old, unmaintained diesel engine and much cheaper to repair. However, I would have liked to have the sound of the 2 cylinder diesel engine. The Honda engine is also more powerful and has less vibration. The big exhaust gives a serious sound a bit like an old big car.

I installed the engine keeping the original engine controls working in case it was removed. The controls are duplicated next to the seat.

Winch with contactor installed inside and not on the winch to release the fan from the motor. Control buttons on the dashboard and on a wireless controller.


Now everything is functional, but the finish will still be a lot of work because I have so many details in mind.

 

[Tinhack]

You have been blessed with exceptional talents. That looks like it's going to be one of the "fun to work" machines.

And I just can't believe that garage floor. Did that used to be your living room?

 

[defranks]

Man! I'm impressed. I wish I lived near you, I'd volunteer some time just to learn a thing or two. I'm pretty good at starting projects, but not so great at finishing them. Great job!

 

[BFreaky]

Great job, can't wait to see it dig