Mini Ex Quick Attach Build

[Jnasystems]

Hello all,
I am thinking about building a quick hitch for my NH EC35 and have some questions about design and machining. First the design, the thought is to create a hook on the front and just pin the back, will this be strong enough to handle the stress? It will be all half inch steel and the tubes will have 5/8" walls. Here is my design:

The next question is how to machine the tubes. I can't find the right size exactly, but I do have a lathe that should be fine for the job. I found new stock that will need 1/8" removed from the inside diameter for $65 and solid 3" bar for $12. Would it make sense to bore the 1-5/8" hole for the pins? Or would that just take forever? Here is the lathe I have - http://www.grizzly.com/products/12-x-39-Large-Combo-Lathe-Mill/G4791.

Thanks,
Joe

 

[Tags]

Joe, I certainly don't want to tell you not to build this, but, it may be cheaper and easier to buy one. The r&d has already been done by the manufacturer and everything will fit up correctly and won't bend or break. Do a search in Google for "mini excavator couplers" or for "mini excavator attachments" there are tons of aftermarket companies that make couplers for that size machine that are very reasonably priced.

 

[High Compression]

Tags might be right, however quick couplers for small hoes are difficult to find. Your design looks very similar to my larger excavator couplers though. I had one custom build by a company called AIM for an unusual applilcation. They were very helpful and it fit perfect and worked perfect. Mine was hydraulic though. You flip a switch in the cab to latch and unlatch it.

 

[Jnasystems]

I got a couple buckets from aim and I was very impressed with them, so when I started thinking about a quick attach they were the first (and last when I heard their price) call. It was several thousand dollars, but it was hydraulic operated. I just want something simple and I have all the equipment, time and desire to build one - now I just need to figure out the details. When this build is said and done, I will have about $100 in it if what I think will work does.

 

[High Compression]

I got a couple buckets from aim and I was very impressed with them, so when I started thinking about a quick attach they were the first (and last when I heard their price) call. It was several thousand dollars, but it was hydraulic operated. I just want something simple and I have all the equipment, time and desire to build one - now I just need to figure out the details. When this build is said and done, I will have about $100 in it if what I think will work does.

Yeah I think mine was $6000. It was worth every penny for my business though. My employees were more likely to use the correct bucket for the job because is was so quick and simple.

 

[Jnasystems]

Well, I did more searching and found several, but none were anywhere near what I would consider reasonably priced. Here is the cheapest I could find
http://www.everythingattachments.co...er-for-4-5-Ton-p/am-q2-1-4-5ton-minihitch.htm
and at 10x my cost I figure I can spend some time on it. If I could find one for under $500 I would consider it, but this is just for use around the house so I won't be making any money with it and I spent less than $15k on the mini in the first place. Just can't justify the cost.

I think I do feel more comfortable about the design though. The one listed above seems far lighter than what I have planned, so I won't worry about that any more. I am going to make a foam model of it this weekend. I will use it to fine tune the design before I commit it to steel. I will take pictures of the model and post them here.

Thanks,
Joe

 

[Tags]

I give you alot of credit for building your own. Looking forward to following your build, remember lots O' pics please....

 

[Jnasystems]

Here is a picture of the templates on a piece of wood to build a model of it to put on the excavator and check fit. I made some changes from the design above because of fit issues with paper cutouts.

 

[Gene :^)]

I saw this thread and decided I wanted to build one too. But then some questions came to mind...

1. With this device you pull one pin to change buckets, why not just convert the two original pivot pins to quick pins and just have to remove two pins to change buckets?

2. This device changes the pivot point of the bucket, does it reduce curling power of the BH? Because it effectively lengthened the mount/bucket.

Gene :^)

 

[aczlan]

I saw this thread and decided I wanted to build one too. But then some questions came to mind...
1. With this device you pull one pin to change buckets, why not just convert the two original pivot pins to quick pins and just have to remove two pins to change buckets?

With the hook on one side, you can pick the bucket up, then put the pin with the bucket nice and lined up. With the 2 pin method, the both have to line up at the same time with the bucket on the ground.

2. This device changes the pivot point of the bucket, does it reduce curling power of the BH? Because it effectively lengthened the mount/bucket

Yes, but probbaly not by much.

Aaron Z

 

[Jnasystems]

Well, I built the model - I think it will work well. I did learn that all 3 of my buckets are slightly different sizes though. Luckily the one I started with had the pins the closest together, so the others should fit, just a little looser. I didn't make the pin sleeves yet and those will go into the model before I start assembling the real deal to make sure nothing binds, but I feel like things are coming together.

 

[Jnasystems]

Got a bunch done today. Machined the top set of sleeves and got the bottom 2 cut to 1/8" over. Now I have a problem - I don't know how to hold the bottom sleeves to bore them to the right diameter. I put them in the chuck, but they wobbled too much for me to feel comfortable cutting on them. Any suggestions? Here is the latest pic.

 

[Gene :^)]

aczlan, Thanks for the great answers. Makes perfect sense now, why didn't I think of that :^)

Now I have a problem - I don't know how to hold the bottom sleeves to bore them to the right diameter. I put them in the chuck, but they wobbled too much for me to feel comfortable cutting on them. Any suggestions?

I don't understand what you are asking? Perhaps a photo of how you tried to chuck it, so we can figure why it would wobble. A piece of round stock should just go directly into the chuck and then use a boring bar, twist drill, or reamer.

Gene :^)

 

[tonyoz]

In Sydney Australia 2 weeks ago a full bucket detached from an excavator quick hitch killing a truck driver standing beside his rig. The excavator operator failed to insert the safety pin and is now in deep poo. Any quick hitch, manual or hydraulic with a latch tounge can release without a safety pin.

 

[hazmat ranger]

Others have talked about Drawn On Mandrel tubing (DOM) for bushings. I've looked at online suppliers and they have various wall thicknesses and varying ID tolerances.
Have a few projects myself and think this is a better option than turning my own bushings.

 

[ManAtArms]

Can you tack weld them to a jig temporarily for machining and then just grind off the welds when done?

Got a bunch done today. Machined the top set of sleeves and got the bottom 2 cut to 1/8" over. Now I have a problem - I don't know how to hold the bottom sleeves to bore them to the right diameter. I put them in the chuck, but they wobbled too much for me to feel comfortable cutting on them. Any suggestions? Here is the latest pic.

 

[jinman]

I have a quick hitch on my TLB backhoe bucket (photo). While I've noticed no degradation in strength, it does extend the length of the bucket so that it now hits the bottom of the boom if I'm not careful. Most of the damage to the boom was done by the previous owner. I try to curl the bucket and bring in the dipper slowly until it makes contact with the boom. My quick hitch is a bit loose and and does add some slopiness to the bucket. If your bushings are nice and tight, that might not be a problem.

 

[Jnasystems]

Can you tack weld them to a jig temporarily for machining and then just grind off the welds when done?

That's a great idea, but I will have to file it away for next time as I found a machine shop that was willing to machine them for a case of beer.

Not much else has been done since as other projects got in the way. Maybe I will have some time this weekend to finish drilling the 3" holes in the .5" plate. Those take for ever with a hole saw, maybe I should crank up the drill speed some. I dread the 1" piece that I need to drill.

 

[Jnasystems]

Well, I finally got all the parts cut out. Now the grinding begins. I will have a bunch to do since they were cut freehand for the most part.

 

[tlbuser]

Wow, wish my freehand cutting was that good! Is this modeled after the JD or Cat in your picture?