3320, 485 BH order is in!

[CinderSchnauzer]

Cinder,
I think it adds stabilty when moving the tractor around, that's why they advise it.

Rob

Warned you all it was my stupid comment of the day.:confused2: You guys are too sharp. Why didn't I think of that - actually have to move the tractor sometimes.

 

[Rob-D]

Dave,
I agree, When you start adding extensions to a machine you increase the torque the tranny sees. F=MD (force = mass x distance) a one pound weight at one foot = an 8 ounce weight at 2 feet. This is why Deere sells BB extensions.

Fish,
As far as the aluminum housings go they are stronger (with caveats). You have to understand the different caracteristics of metals. Think about this, would you rather fly in a plane with cast iron wings or aluminum? Aside from the weight difference the aluminum has the ability to flex and absorb forces that the cast iron doesn't, it would crack because cast iron handles compression forces not flex forces. Now take two long rods and make one out of cast iron and another out of aluminum. Drop a weight on the end of the aluminum and on the end of the cast iron. The cast iron will break because it has no give while the aluminum will flex and absorb the weight. Same with axel housings. What's important is to support the housing with ribs because they distribute stresses and Deere does that. they're castings are outstanding.
Rob

 

[dfkrug]

As far as the aluminum housings go they are stronger (with caveats). You have to understand the different caracteristics of metals.

You can make a structural element out of cast aluminum that is as strong
as one out of the modern ductile cast steel, but it will have to be much
bigger in the critical dimensions. The section thickness that JD uses
where the axle housings' center bolts are are huge, but they have still
had failures when backhoe brackets are added.

The 3-pt hitch lower arm clevises can not be made large enough out of
aluminum to avoid failures, so JD changed the design for the 3x20 to add
some steel over the Al.

JD's 3x20s now use a cast Al center rear gearbox, replacing the cast
steel unit used on its predecessor, the 4x10. Now the axle housing bolts
must thread into aluminum, which is not going to handle the same
forces as the previous design without being a lot longer.

Regardless of my opinions here, it is very interesting that other tractors
of this class (Kubota, NH, etc) use steel in this area and not Al.

 

[Spudland_Dave]

Regardless of my opinions here, it is very interesting that other tractors
of this class (Kubota, NH, etc) use steel in this area and not Al.

I'm with you...all personal theories/thoughts/ideas aside, I'd like to know the exact reason too.

Aluminum is typically more expensive then steel...but true you would have less LBS of Aluminum then Iron...

As for your comment on the threading of fasteners...I have no clue if JD uses em, but there are many various inserts available which more then overcome that issue. With proper fasteners, I'd bet you could achieve a better/stronger fastener interface then with a Cast Iron housing.

Rob-D, my bro is a professional Mechanical Engineer and he said basically the same thing... a PROPERLY Designed Aluminum casting can/will be stronger then an iron equivalent in pretty much any application. Well...maybe except in the case of wheel & suitcase weights. :laughing:

 

[soulasphil]

Regardless of my opinions here, it is very interesting that other tractors of this class (Kubota, NH, etc) use steel in this area and not Al.

I have nothing against aluminium but where is all this aluminium supposed to be ? Most of the parts I can see tend to rust ...

 

[Rob-D]

Nice tractor, love the R1s!
I think they use aluminum on the rear gear reduction axle housings.

 

[dfkrug]

I have nothing against aluminium but where is all this aluminium supposed to be ? Most of the parts I can see tend to rust ...

Take a magnet to the rear of the tractor.

Here is a photo of the rear of a 3520. I have posted pix of the 3120 in
another thread.

I like how JD has beefed up the axle housings, vs. those on the 4310, but
I find the move to more aluminum to be puzzling and troubling. The move
to a cast steel lower ROPS bracket is interesting, but it means that adding
a hoe subframe that welds on there will be tougher, requiring it to be
replaced. The steel pin I noted is grafted onto the axle housing to beef
up the 3-pt arm pivot ears. Very unusual....I wonder how it is attached.

The 3-pt cyl housing is still cast steel and made by HEMA of Turkey. The
toplink anchorage is part of the housing and needs to be of steel. (I see
you have used two of the hole pairs to support your sickle-bar mower...nice.)

Although threaded holes in Al can be made stronger via use of helicoil-type
inserts, this additional process would add yet more production costs.

 

[soulasphil]

Take a magnet to the rear of the tractor.

Thanks for your excellent picture, I won't need the magnet now.
I wonder why they are doing that, I mean mixing steel and aluminium. Especially surprising in a tractor where weight is no problem, we all add weight to get more traction.
The only problem with the back end of the 3x20 I've read about on TBN was with one of the holes for the toplink ripped out. But that is a cast iron part and judging from the pictures it seemed due to a faulty cast, so no real cause for complaint so far.

 

[Rob-D]

Thanks for your excellent picture, I won't need the magnet now.
I wonder why they are doing that, I mean mixing steel and aluminium. Especially surprising in a tractor where weight is no problem, we all add weight to get more traction.
The only problem with the back end of the 3x20 I've read about on TBN was with one of the holes for the toplink ripped out. But that is a cast iron part and judging from the pictures it seemed due to a faulty cast, so no real cause for complaint so far.

Deere does it for strength.

DF, are you talking about not being able to weld cat iron? Do it all the time. There's a MIG wire for it but I've used the regular wire in a pinch.

Rob

 

[jd3020u]

R1's can be spaced to 56.6" on center vs 43.7" for large R4's. Thats 12.9" wider. Evidently Deere thinks its axles are strong enough for 12.9" worth of extension. Now with a backhoe on it might be asking for trouble. I don't know if they're compatible with R1's

Tim.