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It's BIG, Yellow and digs holes! JCB 3CX Project 8 is joining the Tractor Shed

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awemawson:
That is a ditching bucket being used to fair up the sides of a ditch, which is pretty much exactly what I will be using mine for initially - I've about 1/2 - 3/4 mile of ditches to clear.

The 'Extradig' is to extend the 'dipper' further. The back end has a 'boom' pivoted on the machine, with the 'dipper' pivoted on the 'boom', the 'extradig' is a co-axial  very stout square tube partially inside the dipper that can be extended by a foot pedal. It is this inner tube that has the buckets and other attachments on the end.

Using this construction with the extra dig gives the 3CX a total 'stretch' of 7 metres (21 foot) from the machine, which I need to reach to the far side of ditches as clearance can only happen from one side.

A '360' machine (ie one where the boom and dipper along with the cab are mounted on a turntable) is far easier for ditching as it can drive parallel to the ditch as the work progresses. However a '360' with a 7 metre reach is a very big and expensive machine - probably 30 ton whereas the 3CX is 'only' 8 tons.

Incidentally, for the anoraks, the machine that Russ posted is either a 'Project 12' or a 'Project 21' - the give away being the way that the boom is swiveled. All the 3CX's pivot the backhoe assembly on a massive king pin, and up to and including 'Project 8' this kingpin has a 14 tooth heavy duty gear splined onto it, and two small hydraulic cylinders push a rack past this gear rotating the boom. The later model have a pair of hydraulic cylinders bearing directly on the king post thus turning it left or right. You can just see them in the photo.

djc:

--- Quote from: Pete W. on October 07, 2021, 05:49:57 AM ---...a digging machine that can dig with offset - with the diggers I see you have to either position the machine astride the trench or to dig obliquely (slant-wise) across the trench.
--- End quote ---

One of the things machine designers need to consider is how to get the forces seen at the pointy end of the bucket back up the arm of the machine, into its superstructure and back down to the ground upon which it is sitting. They need to do this for all possible positions of the boom making sure the machine does not tip over.

In the standard configuration of a (360) machine, with it astride the trench, the machine end of the arm is very close to its centre of rotation and the counterweight on the back is opposite the boom. This gives maximum stability or maximum force-exerting potential for a given amount of stability. When you do things like offsetting the boom, the stability or bucket force or both are considerably reduced. In the picture above, the machine is a lot less stable digging over the side than with the arm central and facing rearwards. You have to trade off versatility for speed or power.

The sideshift with vertical stabiliser legs is a little peculiar to UK and Europe. If you look at US-model backhoes, the boom is invariably centre-mounted and the stabilisers when deployed exceed the width of the machine.

awemawson:
JCB have made both styles for quite a few years now. The centre mount with 45 degree stabilisers is known as the 1400b or some such title in the states.

When operating side shifted to the extreme, and the rear leg inevitably on relatively soft earth being the top of a ditch, the massive 4 in 1 (or 6 in one in my case) front shovel restores stability but tends to twist the machine. This can be augmented by putting a ton of ballast or even earth in the front shovel.

When ditching the extreme extension of the dipper and 'extradig' obviously exerts huge torque, however there is no need to actually lift when so extended as you are scraping the far bank and ditch bottom so the forces are actually upwards on the boom and dipper. As the extradig is pulled in and boom swung back over land to dump what you have scraped the geometry becomes far better !

awemawson:
Well guess what turned up today  :clap: :clap: :clap:

Various things have conspired to delay the delivery of my new toy. I had made contact with a transport firm that was only 1.5 miles from where the 3CX was lying,and arranged a reasonable price for delivery. The father of the chap I bought it from was supposed to drive it the short distance to the transport yard and it would go at the next opportunity which was to have been last week - that all fell through when he ended up in hospital  :bang:

The seller drove it to the transporters yard who kindly sent me photographs of it safely in his compound to await the next opportunity which turned out to be this morning.

On a beavertail lorry it safely got under the multiple telephone lines and 415 volt 3 phase lines that cross my drive (phew!) into the farm yard where the very nice driver (who was actually the owner of the company) unloaded it and put it my Tractor Shed. Oh good - it does actually fit  :thumbup:

Now I have decided to let the excitement calm down and NOT drive it for a bit - you can do a LOT of damage in a short period! I even got the delivery driver (who co-incidentally has owned one in the past) to park it up for me in the Tractor Shed.

. . . evaluation phase starts now !

awemawson:
Now the cab is absolutely full of junk - old bits of rag, drinks cans, grease tubes mud - you name it. When I can face it I need to take several black bin bags full of grot out, and vac and sweep it out to see what remains.

Things that I KNOW are needed:

Glass for instrument cluster (declared broken by seller so no surprise)
Two rear view mirror glasses - simple plain mirror no heaters!
A plastic 'stone guard' that fits behind the rear chassis frame (plain flat plastic 3 mm sheet easy to make)


Then I need to give it a good service. A full filter kit covering engine oil, gearbox oil, hydraulic oil and air cleaners plus diesel filters.

Then a good greasing - I already have in stock about a dozen genuine JCB 400 ml tubes of grease - it looks like I'll need quite a bit - there are 70 (yes 70!) grease nipple on this machine  :bugeye:

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