Backhoe- Build or Buy?

[wmgeorge]

BG, you can lift the lower arms of a 3ph without moving the lever on all the tractors I have had experience with, the links are able to move allowing you to lift the lower arms. Yours must be an different design, my mistake, I'd be interested to see a picture, apart from the brace with effectively locks the 3ph that dfkrug mentions I dont know of any other way of preventing it lifting.

The problem is not so much breaking the tractor in half (but thats still a consideration, but your loader frame will probably prevent that), but ripping the toplink bracket out the housing. Most of the digging force (several thousand lbs even with 16HP) will be concentrated on it.
I can tell I'm got going to convince you though

Thanks. The tractor is only 12HP. Weighs 2000lbs or there abouts. 6'2 loader lift, 6' backhoe dig depth.

Correct there is no downward pressure, only the 600 lbs or so that the BH will weigh. But the hydraulic circuit on the tractor is open center, series control valves. The 3 Point is last in the circuit, so when the BH valves are being operated there is little or no pressure back to the 3 Pt control valve, which still must be activated. Granted IF I was setting on the BH seat and reached over to raise it up, that could be a problem. Ouch!!

The Caddigger design uses a shoe or gripper on the stabilizer arm made from 4 x 6 steel angle that is forced into the ground at a angle to the bucket digging back toward the tractor.

The top link is held to the rear axle & 3 point area by 4 Grade 5 by 1/2" bolts... Tension capacity = 18,139 lbs each, the Shear capacity = 14,730 lbs each, and the top link support is 3/8 welded steel. Yes, these could fail, but not with the HP this tractor is generating.

IF I was using this everyday, or depended on it to make my living, I would have a dedicated tractor or machine.

My big job now for the moment is wondering what to do with the 300 lbs of steel I have setting outside .
I have a steel beam inside, overhead with trolley and chain hoist in my shop. Good thing I have a couple months before I actually need to use the backhoe.

Is your backhoe your own design, I'm impressed with the capacity!!

 

[shvl73]

I may be mistaken but, I thought the danger was from using downpressure on the hoe causing the whole unit to rise, crushing the operator against the rops. My unit had the additional braces that triangulated the hitch. I have since adapted it to be subframe mounted. Maybe dfkrug or someone else can tell us the specifics of the additional bracing.

 

[wmgeorge]

I may be mistaken but, I thought the danger was from using downpressure on the hoe causing the whole unit to rise, crushing the operator against the rops. My unit had the additional braces that triangulated the hitch. I have since adapted it to be subframe mounted. Maybe dfkrug or someone else can tell us the specifics of the additional bracing.

Sure, I can see that if you are using the bucket to backfill and tamping the ditch. But regular digging would tend to pull it downward and back against the stabilizers. Since I have a loader on my tractor, that will be my backfill pusher.
I could use a short chain and hook to attach to my drawbar pretty easily if I was backfilling with the bucket.
I may just consider leaving the quick hitch on the 3 point and attach to that, I'm going to guess that this would put too much pressure on the quick hitch.

 

[wmgeorge]

I just spent some time on Google searching, and I'd like someone to point me to where the 3 Point hitch mounted backhoe accidents are reported? People getting crushed when the 3 point backhoe rises and crushes people. I did not find anything on the OHSA site, except for the ongoing trench and people getting hit with bucket accidents.

With various searches failing to find these accidents, which I can see happening, just wondering where they are documented and how common are they???

 

[dfkrug]

WMGEORGE, I am sure that crushing accidents involving unbraced 3-pt
mounted hoes are extremely rare. I first heard about it happening on
TBN or TractorPoint years ago. Searches thru the archives will be hard
to filter to track down those early references.

You are correct that fixed outriggers will be hard to use without being
able to lift and lower the hoe with the 3-pt. If you do not go with hyd
outriggers, you will prob want to use the 3-pt unbraced as you planned.

SHVL73, I looked thru some of my pix files and did not find any good ones
to post that show the braced 3-pt. If another poster does not rise to
the occasion, then go look at one of the Woods PDF installation manuals
on their website....they have a drawing. I think 3RRL posted a drawing in
06, which showed his 3-pt brace. He has since tossed it in favor of a
subframe.

I also wished I had saved some of the pix I have seen of failed toplinks.
My most vivid recollection is of the TL bracket pulling a chunk out of the
casting it was bolted into, on an L Kubota.

 

[wmgeorge]

WMGEORGE,
I also wished I had saved some of the pix I have seen of failed toplinks.
My most vivid recollection is of the TL bracket pulling a chunk out of the
casting it was bolted into, on an L Kubota.

I think the "L" series is 30 HP plus, this tractor has 16HP and is cast iron construction. I'm wondering if the Kubota uses aluminum or cast iron like my John Deere? The rated ripping power of the 608 Caddigger is 2,600 lbs at 1,900 PSI Hydraulic pressure. I'm sure you've read my other posts... this tractor can not generate enough power given the size of the hydraulic cylinders and available HP to pull one 1/2" grade 5 bolt apart. IF the casting was defective, at all 4 locations, perhaps, if the HP was doubled to 32 perhaps. I'd trust the John Deere engineering department on this one.

 

[dfkrug]

I think the "L" series is 30 HP plus, this tractor has 16HP and is cast iron construction. I'm wondering if the Kubota uses aluminum or cast iron like my John Deere? The rated ripping power of the 608 Caddigger is less than 5,000 lbs. I'm sure you've read my other posts... this tractor can not generate enough power given the size of the cylinders and available HP to pull one 1/2" grade 5 bolt apart. IF the casting was defective, at all 4 locations, perhaps, if the HP was doubled to 32 perhaps. I'd trust the John Deere engineering department on this one.

Most of these CUTs have a cast steel 3-pt cylinder housing that the
toplink bracket is bolted to. The axle housings are also cast steel, but the
PTO/differential housing is often cast Al. Usually the smaller the tractor,
the lighter duty the housings. There is not necessarily the same
relationship betw hp and strength or weight. My JD955 had 33hp but only
weighed about 2000lb naked. The 3PH and rear housings were pretty
light duty. I have also had two 20hp 2000 lb tractors with heavier duty
castings (Kubota B21 and Kioti CK20).

That said, the forces you place on the rear of your tractor will be a
function of the hyd press, cyl sizes and leverage. If you can deliver
4-5 GPM at 1500 psi to your hoe, that will take maybe 10-12hp. Increasing
the hp of the engine does not increase these forces. CADPlans advises
using no more than 1500psi on their CADDiggers. Even at that pressure,
I broke several things on my 728.

As for the JD engineering dept, they say do not put 3-pt hoes on their CUTs.
I am not saying you have to follow their recommendations...just be aware
them and why.

 

[wmgeorge]

As for the JD engineering dept, they say do not put 3-pt hoes on their CUTs.
I am not saying you have to follow their recommendations...just be aware
them and why.

Thank you for your reply and concern, my reference was to John Deere engineers in general, I have a friend who is a retired JD engineer here in Iowa. When I get time I'll ask him what the failure rate is on 3 point top links. I did edit my posting, the ripping force of the 608 bucket is 2,600 lbs at the rated PSI of hydraulic pressure.

As a Caddigger owner you know how they work, the digging pressure is suppose to push down and back against the stabilizers.

How did this work in the real world?

Did you later on make yours hydraulic?? I may make sure I leave room on the valve mount for another spool!!

 

[MJPetersen]

I may make sure I leave room on the valve mount for another spool!!

leave room for 2 spools. One for each side.

Mike

 

[wmgeorge]

leave room for 2 spools. One for each side.

Mike

Mike, Thats kind of a duh thing, but I didn't think of it!!
Thanks.