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Author Topic: backhoe from scratch and scrap  (Read 4258 times)

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Offline grouch

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backhoe from scratch and scrap
« on: June 06, 2017, 09:06:12 am »
Is there a hydraulic systems doctor in the house?

My little monster seems to have some bugs in it. I have some parts coming that I think will fix it, but now I'm a little worried they may be a solution to a problem that's not there and may do nothing for the problem that is.

It occurred to me that there are Forestry Forum members who deal with hydraulic systems from dainty to downright awesome every day. Maybe someone will recognize the symptoms and a cure.

After about the 3rd use of my homemade backhoe, one stabilizer cylinder started leaking much worse than before and one of the front bucket cylinders started streaming. Lowering the boom is a bit too touchy -- it tends to bounce hard. It drops quickly, the natural reaction is to let off the control, it stops, the whole machine rocks. My guess is that it's acting as a giant piston pump then and sending enormous pressure spikes throughout the system, faster than the relief valves can react. I'm not sure of anything, though.

The parts I have on the way that I hope will cure it are a double relief valve, a flow control valve, and a 3-1/2 inch cylinder to replace the 3 x 16 boom cylinder.

Any suggestions and speculation welcome.

Here's what the multi-year, spare-time project looked like when it was toothless, but articulate. (This was the first time after several years of working on it that I knew that it would at least move as planned).






Figuring out how to make that stabilizer -- hinge points, lengths, angles -- was the toughest part. 4 inch by 7-1/2 inch cylinder given to me by the owner of a local hardware store and feed mill. Came off a forklift he was scrapping out.


No teeth at the time of this first test at the end of last August.






Those are 11.2-28 tires on 10-28 rims, for scale. About a 9-1/2 ft reach.

Offline dustyhat

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Re: backhoe from scratch and scrap
« Reply #1 on: June 06, 2017, 09:25:05 am »
I want to say cushioning valve but im not sure what something like that is called. Anyway that is one nice looking build you got. sense were both from south central ky. maybe you can come over and use it .LOL.
Running a custom built stationary bandmill with a slightly modded four cyl jeep go devil engine.

Offline grouch

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Re: backhoe from scratch and scrap
« Reply #2 on: June 06, 2017, 09:39:15 am »
Funny you should mention a cushion valve, that's exactly what I have on the way.

Offline grouch

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Re: backhoe from scratch and scrap
« Reply #3 on: June 06, 2017, 10:04:17 am »
First off, I should have mentioned that I don't _need_ a backhoe. That's why this project kept getting pushed down the priority list. It's just I've wanted to build one ever since the first time I saw one as a kid.

Bulldozers are fascinating, but there's a lot of stuff going on that's hidden from view. A backhoe shows all the joints and actions. The way it's powered just adds to the fascination -- those hydraulic cylinders are just slow-motion steam engines with a different fluid going through them. What kid can resist a steam engine? Pressurized fluid pushes a piston and rod one way, move the valve and it pushes them the other way.

Here it is after the teeth were added to the bucket, with its first mouthful:


That's an old dozer pile of mostly sandy top soil, left over from digging a pond.



And the happy (wrinkled) kid playing in the dirt:










A lot of years between the daydream and the realization. 

:)


Offline ljohnsaw

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Re: backhoe from scratch and scrap
« Reply #4 on: June 06, 2017, 11:16:42 am »
I like to make models of things I want to make.  You might have seen my cabin thread where I was unable to work on the actual cabin, so I started a model:

 

Way back (1990's), I had a Case 210B orchard tractor and I just wanted a backhoe - cause they are cool!  I gathered up 3 hydraulic rams - short but fat - that I thought could do the job.  Rather than draw it out to figure out the mechanics, I made a model of the rams and the arms out of some brass stock (from the train hobby shop).  For each ram, I soldered a short section of tube to the rod to act as the piston and stops.  The clevis came off of this one.

 

I made a replica of my tool bar - the thought was to hang the attachment from that on the 3-point ::)  The arms used here were just for getting the layout.  The actual backhoe would have been much more robust steel tubing and rod mounts.

 

 

It wasn't until last year that I bought my Davis Little Monster.  A whole lot easier than building!!!

 

(oh, yeah - I made this while I was at work, supposedly programming... ;) )
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 38" cut Bandmill up to 64' - using it all to build a timber frame cabin.

Offline grouch

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Re: backhoe from scratch and scrap
« Reply #5 on: June 06, 2017, 11:28:05 am »
I like the cabin model and the brass model.
Not so much the bought backhoe: The boom looks too short and the radius of the bucket seems wrong for the pivot. Don't guess it was designed to dig basements, though.  ;D

I did my drawing in Qcad and later LibreCad and, of course, scraps of paper or whatever was handy. Modelling was done in cardboard and OSB.

Offline Ox

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Re: backhoe from scratch and scrap
« Reply #6 on: June 06, 2017, 12:10:58 pm »
You have the best homemade backhoe I've ever seen.  Very, very good job on that.

You look almost exactly like my uncle.  It's uncanny.  And if you added about 100 lbs and 20 years and change your hat you'd have me.  I'm looking at my future!  T'aint bad...

What is your little Ford's model number?  I can't make up my mind if it's a 2000 or 3000.  Is it a diesel?  I seen a little blue haze in one of them pics.  Thanks for sharing all that.  Pics of machinery is cool.
K.I.S.S. - Keep It Simple Stupid
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1989 GMC 3500 4x4 diesel dump and plow truck, 1964 Oliver 1600 Industrial with Parsons loader and backhoe, 1986 Zetor 5211, Cat's Claw sharpener, single tooth setter, homemade Linn Lumber 1900 style mill, old tools

Offline snowstorm

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Re: backhoe from scratch and scrap
« Reply #7 on: June 06, 2017, 01:07:06 pm »
Usually the pressure would be set lower for boom down than up. The return oil on boom down is just going back to tank. Some also use a smaller hose on the down side of the. Cylinder. A cusion valve in the swing would be a good idea most do. Lock valves for the stabilizer would keep them from drifting

Offline ljohnsaw

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Re: backhoe from scratch and scrap
« Reply #8 on: June 06, 2017, 03:47:22 pm »
I like the cabin model and the brass model.
Thanks.
Quote
Not so much the bought backhoe: The boom looks too short and the radius of the bucket seems wrong for the pivot. Don't guess it was designed to dig basements, though.  ;D
Not a big backhoe by any gauge but it sure was better than digging with a shovel!  At full extension, the tip of the bucket is a 127" reach and can reach down 110".  The boom swings a full 180 which came in pretty handy.  As you see in the picture, it converts into a trailer.  You don't want to drive far with this one, it has a whopping top end of 2.5mph! :D
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 38" cut Bandmill up to 64' - using it all to build a timber frame cabin.

Offline grouch

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Re: backhoe from scratch and scrap
« Reply #9 on: June 06, 2017, 05:44:33 pm »
You have the best homemade backhoe I've ever seen.  Very, very good job on that.

You look almost exactly like my uncle.  It's uncanny.  And if you added about 100 lbs and 20 years and change your hat you'd have me.  I'm looking at my future!  T'aint bad...

What is your little Ford's model number?  I can't make up my mind if it's a 2000 or 3000.  Is it a diesel?  I seen a little blue haze in one of them pics.  Thanks for sharing all that.  Pics of machinery is cool.

Thank you much for the kind words!

Gotcha on the tractor. It's a 1980 Long 310. (service manual). Long started out in Tarborough, NC and passed through Romania and Canada on the way to becoming FarmTrac or something like that. It's a licensed near-copy of a Ford. It's a 2 cylinder diesel where the Fords you mention are 3. Almost all Ford parts will fit.

[Edit to add:]
Oh, and that canopy is the entire top off of a 1980 Renault LeCar. Period correct, doncha know.

Offline grouch

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Re: backhoe from scratch and scrap
« Reply #10 on: June 06, 2017, 05:48:47 pm »
Usually the pressure would be set lower for boom down than up. The return oil on boom down is just going back to tank. Some also use a smaller hose on the down side of the. Cylinder. A cusion valve in the swing would be a good idea most do. Lock valves for the stabilizer would keep them from drifting

So I'm on the right track with a double relief and a flow control valve on the way?

My swing uses 2 cylinders and they start fighting each other near the limits of swing so it's kind of a built in cushioning. The only problem is that it has less and less force near those limits, too. I tried to copy a design by a Canadian on some machinery forum (wish I had a link to give him credit; it was a fine job on an old tractor).

Offline grouch

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Re: backhoe from scratch and scrap
« Reply #11 on: June 06, 2017, 05:51:54 pm »

Not a big backhoe by any gauge but it sure was better than digging with a shovel!  At full extension, the tip of the bucket is a 127" reach and can reach down 110".  The boom swings a full 180 which came in pretty handy.  As you see in the picture, it converts into a trailer.  You don't want to drive far with this one, it has a whopping top end of 2.5mph! :D

That thing can move itself without just pushing with the bucket?

Mine had a low bar to meet -- just be easier than a pick and shovel. If I have to, I can get along with pick, shovel or clamshell post hole diggers for a little while, but I don't like to. ;D

Offline ljohnsaw

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Re: backhoe from scratch and scrap
« Reply #12 on: June 06, 2017, 06:57:59 pm »
That thing can move itself without just pushing with the bucket?

Yep, an 18 hp Wisconsin twin engine coupled to a hydraulic pump.  Has a small hydro motor connected directly to a differential.  There is a lever to pull it out of gear when you want to tow.  The whole thing weighs ton!  It is really heavy.  I can barely get it up some of the steeper part on my property.  I think it was designed to be used in tract home developments.
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 38" cut Bandmill up to 64' - using it all to build a timber frame cabin.

Offline snowstorm

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Re: backhoe from scratch and scrap
« Reply #13 on: June 06, 2017, 07:12:41 pm »
When the boom goes down the oil goes back to tank with little pressure. Case used a regeneration valve to help speed things up. That's more complies than what you need. What are you going to use the flow control for? They are used to slow things down. A simple open center system will not multi fiction very well. It's just the way it is

Offline 21incher

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Re: backhoe from scratch and scrap
« Reply #14 on: June 06, 2017, 07:50:37 pm »
Nice job on the build. You have to watch what psi the cylinders are rated for. Once you seal off a valve the geometry of the mounting and external loads applied can cause some pretty extreme shock loads that can cause seals to fail that is why the cushion valve should help. My little lightweight trencher uses 3 inch cylinders with 10,000 psi hoses, I am guessing you may need some larger cylinders at a slightly lower pressure to smooth it out. :)
Hudson HFE-21 on a custom trailer, Deere 4100, Kubota BX 2360, Echo CS590 & CS310, home built wood splitter, home built log arch, and a logrite cant hook.

Offline grouch

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Re: backhoe from scratch and scrap
« Reply #15 on: June 06, 2017, 08:19:55 pm »
When the boom goes down the oil goes back to tank with little pressure. Case used a regeneration valve to help speed things up. That's more complies than what you need. What are you going to use the flow control for? They are used to slow things down. A simple open center system will not multi fiction very well. It's just the way it is

I intend to put the flow control valve in the down circuit for the boom cylinder. My thinking is that if it can't be dropped very fast even with a wide open valve, it can't bounce the whole tractor regardless of operator experience. (Last time I used a backhoe was early '80s and then only occasionally).


Nice job on the build. You have to watch what psi the cylinders are rated for. Once you seal off a valve the geometry of the mounting and external loads applied can cause some pretty extreme shock loads that can cause seals to fail that is why the cushion valve should help. My little lightweight trencher uses 3 inch cylinders with 10,000 psi hoses, I am guessing you may need some larger cylinders at a slightly lower pressure to smooth it out. :)

Thanks!

The 3-1/2 inch cylinder is on backorder. That's as big as I can go without having to change the mounts. Should've designed in a little more clearance for the body of the cylinder at its extremes. My hoses are 4000 psi and all relief valves are set at 2000 psi. I don't know what pressure it really runs at but have a gauge on the way, too.

I expected bugs to have to work out but didn't expect to blow out seals. Not sure that's what happened, but it seems reasonable.

Offline grouch

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Re: backhoe from scratch and scrap
« Reply #16 on: July 03, 2017, 06:27:59 pm »
All the parts and pieces have come in, but I'm still bogged down in other stuff. Those scalawags at Surplus Center told me some parts would be on back-order until July 11, but the last of the order came in over a week ago! They just want me to stop lounging around and get back to work.

Meanwhile, I forgot to post these photos. My daughter is a programmer. She was not much interested in operating the backhoe until I told her to just act like it's one of those crane things at a county fair you try to pick up prizes with.

Instructions given:
"You can operate one lever at a time or as many as you can handle, just don't swing it left or right unless the bucket is free and clear. It's like side-loading a knee -- the thing that ends careers for basketball players. Swing left, right; boom up, down; dipper in, out; bucket curl, uncurl. Other than not using swing to push things sideways, if something breaks on it, I didn't build it strong enough."

She was much relieved by that last one and ready to give it a try.









Thought I was never gonna get her off that thing.

Offline Ox

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Re: backhoe from scratch and scrap
« Reply #17 on: July 04, 2017, 09:46:58 am »
No rocks!  If you need some I grow them here.  They sprout right up out the top of the mountain every year!
K.I.S.S. - Keep It Simple Stupid
Use it up, wear it out, make it do or do without
1989 GMC 3500 4x4 diesel dump and plow truck, 1964 Oliver 1600 Industrial with Parsons loader and backhoe, 1986 Zetor 5211, Cat's Claw sharpener, single tooth setter, homemade Linn Lumber 1900 style mill, old tools

Offline grouch

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Re: backhoe from scratch and scrap
« Reply #18 on: July 04, 2017, 10:04:09 pm »
I have rocks, they're just crumbly. :)  Anywhere you dig around here, you hit sandstone. It's only a problem about 2 ft down. That's where it will wear out buckets and teeth. These test digs were in a 'dozer pile of mostly topsoil that needs to be spread over the pond dam.

When my son's basement was being dug -- by my neighbor with his big Kobelco trackhoe -- I could feel the vibrations through the ground about 300 yds away as the teeth were scraping through the sandstone. The teeth on a little Kubota backhoe were worn down to nubs digging the footer. It's pretty amazing for something you can crumble in your hands. Tensile vs. compression, I guess.


Online gspren

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Re: backhoe from scratch and scrap
« Reply #19 on: July 05, 2017, 08:28:59 am »
  I'm impressed, it looks like a lot of thought in the design and building. Also I guess you already know your daughter is much better looking than you. ;D
Stihl 041, 044 & 261, JD 2355 4X4 w/fel, JD 620, Yamaha Kodiak 400 & trailer, Kubota 400 RTV,  P&M OWB, 75 acres to play.