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Discussion Starter · #1 ·
Since I'm now the proud owner of new 485 backhoe for my JD4500, I'd like to add a thumb. The post 2011, 485's can take a factory thumb (pricy too). Mounts on the front bucket pin and there's a mounting point on the dipper for an extension stick (hydro later, sparky). Is only compatible with 16" and up buckets because of clearance issues. I have a 12" bucket. It's about $2500 for 16" bucket and thumb, I think I can do better than that plus gain usage with 12" bucket.

Thought about this a bit and if I add a quick coupler, then thumb mounts off quick coupler front pin and clearance issues are solved AND don't have to remove the thumb to change buckets or other digging implements of destruction.

Some serious googling later, gets me nothing regarding Deere 48/448/485 backhoes and quick couplers. Hard to believe that no one has done this yet. Not worried about decreased lift or digging force, designed right, a quick coupler drops these by 3-5 percent and for the 485, dipstick is 2435 lb, bucket is 3730 lb and boom lift is 820 lb. Plenty of margin. If one designed a lift point on quick coupler, then you can drop the bucket (and it's weight) and actually get closer to max boom lift.

Thought about talking to BXpanded but they don't seem to have time to meet their existing BXpanded product shipping much less take on a new design/project. One option is Mudds for build but I'd rather be prepared for a "you got a design ?" question first. So time to start investigating the design of one.

48/448/485 bucket specs:
Pins, 1-1/4" x 10-1/4 (PT10435)
Ear Inside, 7-3/8"
Pin centers, 7-1/2"

A quick coupler design seems simple, hook, pin, some plates and done... :) Sure, sure. lol. Doing some research, the vertical/horizontal offsets are the critical design parameters. These are diddled to minimize the tip radius change which effects the digging force. Everything else is icing and making sure the material is thick/reinforce enough to keep from ripping the coupler apart vs adding too much weight.

WoodMaxx has one for their backhoe line, pretty cheap too, $260. Clever pin attachment. Might just get one and scale up/down to fit a 48/448/485 backhoe. Call it NRE costs and can sell it off later :)

Has anyone done this before ? If so, how did you determine the vertical/horizontal offsets ? Other tips or hints ?

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Discussion Starter · #2 ·
Another picture regarding breakout force. Nice design but requires bucket changes which is a no go for me. Left off the calc for the 2) figure, it was 20 percent but that coupler is a real sloppy design, too much vertical offset. Time to take some measurements and see what the numbers say for worst case zero horizontal offset.

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Discussion Starter · #3 ·
Back of the cardboard calcs say if the vertical offset is 3" (worst case), the bucket force drops by 11.5 percent, if 2", then 8 percent.
Which is:
3730 * 0.115 = 428.95.
3730 * 0.080 = 298.40.

I could live with a reduction of ~300 lb with a 2 inch vertical offset, might be able go a little under 2 inches, have to see once I make up some models.
 

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Discussion Starter · #4 ·
Three candidates for a closer research look. Sometimes it's good to checkout existing designs and see what works.

1) BXepanded, simple hook and "bang pin" design. Defiantly would need structural changes to handle the forces of a 485. About $360 and impossible lead time. Might as well design from scratch or this becomes a winter project.

2) WoodMaxx, interesting spring clip design. Much easier to install/remove. Would need less structural changes and it's cheap, $260, ships in 24 hours. Get one, refactor design for 485, build it, done.

3) Wallenstein PT7220. Bolt driven, mechanical pin-grab slider. Also interesting as it firmly clamps the bucket onto the adapter removing all the wiggle factors. That's a plus in my eyes over easier install/remove. About $500, cause for pause in getting one for redesign purposes. I'd give my left teeth for bucket measurements for their GX720/GX920 backhoes.

Kubota also has one but their bucket attach is so different than Deere's it would be harder to redesign. Might as well design from scratch.
 

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Thumb on my mini is an Amulet iirc
 

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You recently had the backhoe installed on your rig. Have you done any serious work with it yet?

Gain some knowledge and experience with your new acquisition and then I'm sure you'll be able to set your priorities and budget regarding additional BH attachments.

Select the right size bucket for most jobs. You'll rarely need an alternate size. The 18" HD bucket is a good choice for general excavation and rock work although the 12" bucket is going to be faster for digging stumps and tearing out roots.

A thumb can be as much of a nuisance as a benefit. When you don't need it it's usually in the way and becomes an obstruction.

IMHO street pads are useless unless you're concerned about damaging a concrete or asphalt surface. Off the street these pads will prevent the stabilizers from doing their job and keeping you planted where you'd like to work.

JMHO. 45+ years experience running various rigs from a 20' Dynahoe to a 7' CUT. Your 485 is a very capable backhoe. I've done some things with mine that impressed the daylights out of me.
 

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Discussion Starter · #11 ·
Still waiting for parts to come in from Deere, the replacement drawbar hitch. Once that comes in, the JD4500 minus backhoe goes in to get the rockshaft side plates pulled and everything inspected for any damage. Then tractor side parts get installed properly by a competent Deere service person. Any day now.

So right now, I have a 1500 lbs boat anchor begging for attention :)

Just got done fabricating street pads for it, I will need them for replacing three culverts that cross a blacktop road. More in that street pads thread when I take some new pictures.

Also remote mounted the front swing grease fittings, they are next to impossible to get at when the backhoe is mounted. Stay tuned for a new thread on that project. I'm a grease fanatic :)

I have the 12 inch bucket right now. A 300 foot electrical trench is planned. A larger 18 inch bucket maybe for future.

The quick coupler project is for kicks and giggles. Did tons of metal work decades ago, design/fabrication is my idea of fun.. At one time, long, long ago, I could stick weld aluminum, upside down. Pre MIG/TIG days. Right now, I'm glad I removed the bucket, good practice and revealed a possible lubrication issue. Better to fix it now when everything is new and clean rather than when the pins freeze in place and require lancing to remove.
 

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The Kubota Quick change is nice in that the coupler "is" the Pins. It retains factory geometry.
Bad....buckets are specific to coupler. Ears on buckets will open up a bit over time.
Still way better than some others I've seen. Pin is a bit fussy to slide in after the ears wear . I notice this the most with the Grading bucket which of course is the heaviest to wrestle around.
 

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Nice work mate, I feel like I'm on the same path on the other side of the world! I would love to make a quick hitch for my 485, so I'm keen to watch this space. I too can't believe that there's not an off-the-shelf QH for the 48/448/485, I also can't believe there's not a JD ripper. As for the Thumb, I can't wait to see what you come up with there, $2200AUD plus freight is well outside my budget. I've toyed with the idea of cutting the ears off my bucket as the base for the QH and going with a comparable spec excavator pin size, at least I could get buckets without selling my organs or waiting months. Damn COVID! I've used the Kubota quick hitch which is similar to the Wallenstein's, I like a tight fit and it's easy to carry a ratchet and socket.
 
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Discussion Starter · #15 · (Edited)
Well, just smack me with a trout. Center to center is 7-7/16 inches, not 7-1/2... Oh Deere :)

Slight design change, getting the boom mount with all the needed clearances is a pain in the rear. Done about three 1/2 inch plywood mockups and buzz, not quite right. Problem is the boom on the 485 is very wide and square below the pin mount. So you have to have lots of clearance over the full motion. Then the dipper mount on bucket side has to clear the upper part or it will not slide on the bucket. It's like an N-dimensional puzzle to solve. Every solution I've tried gets me to a vertical offset of 3 inches or more, or a two step slide on to bucket pins for dipper mount with a large angle offset between top and bottom pins.

So rather than deal with altered bucket angles and icky slide on, and since the design is drifting towards a 3 inch vertical offset anyway, let's just start there and see how that works up. 3 inch is a an 11.5 percent force reduction vs 8 percent, or 130 lbs. I could still live with that.

Need more 1/2 inch plywood...
 

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Discussion Starter · #16 ·
Getting closer... Vertical offset is 2-3/4 inches.

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Maybe another 1/2 inch to top mount, above pin holes. There's clearance for it and the additional height would help the retain the strength after the pin retaining bolt holes are located.

Top piece has to be 1/2 inch thick, to match the bucket ear thickness. Bottom piece can be thicker, 3/4 or even 1 inch. The concern is with the lower hook thickness. Not enough meat there and it will just bend and rip off.

That's one of KennyD's 6 foot straps peeking out. It's attached to a pulley and goes to rafters. Used to muscle the bucket around. Much too weak (rafter attach point) to lift or tilt the backhoe...
 

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You all seem to be thinking along the lines i am thinking.... only I have 48a. that is beat to **** by the previous owner, and in dire need of attention and some serious love (and by love i mean replacement steel)

I too am playing with a quick coupler design.... i have wooden mock up pieces being cut on out water jet this week, then mock up and OEM bucket mods so i can use the 100$ brand new 12" JD bucket i picked up at the local JD Ag dealer....

this is not on the hi priority list. fixing the nearly busted off dipper stick and bent dipper cylinder takes top priority....


dark plates and bushing are the update kit for the 2 series (?) hoe bucket. It has a 6" pin center and 1" pins... so i think its for that at least...
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Getting closer... Vertical offset is 2-3/4 inches.


Maybe another 1/2 inch to top mount, above pin holes. There's clearance for it and the additional height would help the retain the strength after the pin retaining bolt holes are located.

Top piece has to be 1/2 inch thick, to match the bucket ear thickness. Bottom piece can be thicker, 3/4 or even 1 inch. The concern is with the lower hook thickness. Not enough meat there and it will just bend and rip off.

That's one of KennyD's 6 foot straps peeking out. It's attached to a pulley and goes to rafters. Used to muscle the bucket around. Much too weak (rafter attach point) to lift or tilt the backhoe...

i would be very interested in comparing our out comes by the way....
 

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Let the games begin! I'm looking forward to how these turn out, too. I've been thinking of a quick hitch to mount more common (in Australia) excavator buckets. Down here, my options are make my own, replace ears on existing buckets.
 

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Discussion Starter · #20 · (Edited)
Nice, 2-1/2 vertical offset. best I have now is a 2-7/8 inch. On the 12 inch bucket I have, the front pin mount has more material towards the front than the top, so to be able to rotate, I needed the extra 3/8 inch drop. I'll try to get a better picture that is less dark :)

What CAD program are you using ? I started with Fusion 360, ugh, steep learning curve on it, kept doing strange things and now they crippled the free version (seriously, no DXF export ?). Switched to Microsoft MacDraft which is ok but sucks as far as snapping correctly to angular lines to curves. All the CAD apps I've used from decades ago are dead now :)

What are you thinking about for the pin retaining bolts ? Unlike the backhoes for series 1/2 tractors, the retaining pin is different design, the hole is very close to the busing edge and bolts on to the bucket/upper plate.
 
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