doug72

Quick video now made: Had to slightly modify undercarriage due to wheels touching battery box when on full steering lock. Camera on a fixed mount hence it goes off camera at times !!! Next step is to determine the size of the rotating upper machinery section & layout of all the motors required.

Thanks - no video yet but I will se what I can do tomorrow need to wait for daylight ! Just tested it and is quite easy to control and smooth running unlike previous MOC ! Only remote functions at the moment are drive and steering plus outriggers by hand. Have secured the battery box better to stop it falling off !! Need to order more 8 x 1 plain tiles to cover technic holes for aesthetics. Working on a simple mechanism for the elevating the operators cabin. Steering problem now sorted and tested OK. Changed the 12/20 to 16/16 gears to transfer down to the axle that has a 12T double bevel gear meshing with an 8L gear rack. Both L Motor & Servo now help support the frames for the outriggers.

Undercarriage completed:- L motor for drive and Servo for steering placed at each end - this extended chassis by 2L to accomodate them. 
Small battery box located on one side between wheels.
 PF Receiver located on the opposite side.

 This means no PF cables have to pass up through the turntable anymore which will allow full 360 deg. rotation. Ourtiggers will remain on manual deployment. Re Servo centring:-
 Minor problem in that return to centre is slightly off due using a 12/20 gear reduction to limit travel and turning angle to approx 40 degs. each way to avoid hitting other parts. Note: Servo centres OK its the reduction gearing that causes the problem. 
Had similar problem with my Boydell Stomper but was able to eliminate it by introducing further 1/1 gears to keep alignment correct. Update:_ Now fixed - stripped down drive from servo motor to the steering rack and re-positioned it - re-assembled and now centering is OK. Side view showing battery box. Side view show underslung PF Receiver which works OK. Underside view Outrigger in stowed position. Outrigger in working position with all wheels off the ground.

I got it on a visit to Legoland UK several years ago, it’s very useful. Markings in the back are ST-0482 & 1 - 01 2008

The closest Lego colour is Lime Green but only a few parts are made, so it will be that favourite colour, construction yellow !?

Thanks: Check out the link to Sennebogen website in early post - which has videos of one in action. Drive & steering sorted with PF Rx mounted between wheels on one side. Other Functions:- 1/. Slewing 2/. Main boom raise and lower. 3/. Dipper arm raise & lower 4/. Open & close a four arm clam shell grab, or an interchangable 2 bucket grab. 5/. Raise & lower operators cabin, probably using a linear actuater manually or PF switch. Rotating upper works can also be mounted on a crawler unit or a rail mounted portal or on a 6 x 6 truck. One version has four interchangable tools for various tasks - now thats would be a real be a challange. https://www.sennebogen.com/en/products/material-handler/sennebogen-830/vario-tool-76.html

Thanks, just added a link to Sennebogen web site for this machine. Would normally post a photo from the site but due potential copywrite issues haven't !!! Under carriage now modified with M motor for 4W drive and servo motor for steering. ( I had to rob Boydell Stomper for the servo !! )

Mobile Material handler: Based on a Sennebogen 817 machine. https://www.sennebogen.com/en/products/material-handler.html My machine will not be green due lack of parts in that colour,

Yes I learnt a lot building the last MOC, which got too complex.

Thanks - No room to fit step up gears for both drive paths for steering & drive. Therefore I have decided to go with either two PF cables through the turntable or alternatively only a cable for a PF Reciever which mounted on under carriage. A stop to be used to prevent full 360 deg. rotation of upper structure.

My next MOC - undecided yet as what exactly the function of rotating part will be but have a few ideas for something different. I had intended to have all motors & a servo in the rotating structure but trials using a co-axial drive through the turntable has this proved to be impossible as slewing would affect both drive and steering functions. 
Both will now have to be re-located within the undercarriage and can have either two PF cables passing up though the turntable with a stop to prevent 360 deg. slewing or located them both in the undercarriage along witha battery box & a PF Rx if enough room. The rotating structure will based on the Ultimate 8043 excavator created by Jurgen Krooshoop - but will be adapted for the possible PF functions I require. PS: one thing for sure the four outriggers will be HOG.

I had hoped to run both the steering and drive from motor & servo located in the rotating structure via a co-axial drive through the turntable but this appears to be impossible as when structure is slewed it affects both the steering and drive. Is there a solution to this problem ? I don’t think there is ! So back to the drawing board.

Have re-configured the turntable connection to under carriage and managed to lose the 1L height, allowing use of the old style differential housing OK.

Thanks - yes aware of that but the turntable is 1L too high so the 16T gear won't mesh with the gear drive to the wheels and keep 24T gear high enough to connect to motor output gears. Seeing if I can lower the turntable so that it does. A new (old) problem: As turntable rotates the drive to the wheels also creeps - I recall this problem with the 8043 excavator when tracks moved as upper section rotated.

Please:

16T clutch gears lost motion. when used for co-axial drive through a turntable: For my next MOC build I require a co-axial drive through a turntable for steering and drive to a 4 wheel under carriage. The co-axial drive requires two red 16T clutch gears, a grey driving ring and an extension driving ring. Drive to steering via centre axle is OK and has no lost motion.
 Drive to wheels via co-axial drive has 180 degs. of lost motion !!!
 (Even more lost motion if use old red driving ring, grey clutch gears and two extension driving cones to get same length) How to eliminate this lost motion with a solution that does not damage parts permanently ? Solution:
BLUE TACK
 The recess in the 16T clutch gears & extension driving ring are filled with a small ammount of Blue Tack.
 Take a small ball of Blue Tack and roll it out to form a rod approx, 1.5 mm dia. 
Press this into the groove and then assembly all parts - squeeze all parts together.
 Result:- NO LOST MOTION & no damage to Lego parts.

Where ?

Thanks, now stripped down ready to start my next MOC once I sort out all the parts back into their correct storage bins. I only keep the better MOCs. still have my TC 8 tower crane. Yes I removed the differentials and powered only one wheel on each caster unit, the other runs free. If you look at the last video you will see a caster unit with one wheel off the ground due to the weight above making them spread. Don’t think there are any Lego events near me in the NE of England. It was an enjoyable process evolving the build but it’s far too large to display in my study / Lego room. For my next MOC I need a servo motor & have to decide which previous build I have on display to rob it from !! Volvo front loader, Fork lift or Boydell Stomper. Doug

New video showing the crane steering, working well but still occassional gear clicking when caster units roate. The rotating structure is quite heavy. Runs best on a hard surface unlike the table cloth I use before ! 98% satisfied with this epic build at last. PS I need to go to crane driving school !! Video:- This the end of the build.

Lego have already retired 42053 - its only available on eBay etc at inflated price.

Thanks for this suggestion - will come in handy for my next MOC - a steered version would be usefull as well.

I have now modified one caster unit and seems to be the best solution - see image. Also able to reduce the wheel speed by using 12/20 reduction. The red axle connector is there to keep the 20T gear in place and is not connected to it. Was able to remove caster unit from turntable OK without any major alterations. Now modified all four caster units and a huge improvement with steering without any gears skipping - just need to remember to have all powered wheels rotating the same way. Tried all steering modes including radial which is OK as long as its not too tight a turn. I will make a new video & post on my Mobile Dockside Crane topic later.

Thanks everyone for all the above suggestions, which in the own right all work. Now attach them vertically under a Z60 turnatble, not so easy or robust and available space restricted once tires on both axles Agree - I was thinking about that last night, power one wheel on each caster unit and leave the other one to spin independently to allow for differing rotational speeds when turning. I will give it a try. A usefull axle would be one with a 5L axle but with stop at 2L from one end allowing it to pass through frame to 12T bevel gear and sandwhich the axle stop with another beam.

Differentials - the “Achilles Heel” for my recent MOC of a mobile dockside crane.

 The use of differentials in the caster steering units was not successful when under heavy load and steering due to the output axles pulling out of the 12T single bevel gears despite using 5.5 axle with stop and side beams to prevent any axial movement. With the old style 16/24T differential you could use a half bush inside the diff casing to help prevent this - with the newer Z28 diff. this is not possible.

 But the old 16/24 diff. cannot be used within a 5 x 7 frame or beam frame with ball joint because of its 4L width. I have tried to use a LEGO Beam Frame with Large Ball Joint (92910) and side beams but was not suitable unless the ball section joint section is cut off to give a “U” shape frame, to mount on a Z60 turntable. 
Another possibility is remove one end of a 5 x 7 frame to give a 5 x 6 ”U”. 3D printing may be a solution rather than cut Lego parts. Discussion, ideas & suggestions please.

Changed the tires to 49.5 x 20 but still some problem. Runs OK for a short while then starts skipping again after performing turns. Traced fault to the caster units legs spreading causing the 12T bevel gears in the differential to lose contact with the wheel axles. No easy way to fix without a full strip down of undercarriage, so I have leaned something !! So on with planning my next MOC which will be multi functional. But first need to finish building the Ship in a Bottle ideas set.