doug72

A great Mini GBC, found your YouTube building instructions but they are a bit hard to follow. Can you post the link so others can easily find them. Doug

Dipper arm now improved and strengthened. Its a large MOC and no idea of how many parts used so far, a smaller verison might make a good set. Thanks for your comments - I too built the 42006. Dipper arm improved:

 Clam shell bucket grab: 
I am attempting to build a rotating clam shell grab but so far result is too large & doesn’t open far enough.
 Grab will be power operated to open & close the grab with manual rotation. Small grab:- not suitable and not possible to remotely open & close. Large grab:- uses two LEGO Shovel 5 x 7 x 4 1/2 with Hole/cross (18943) & small linear actuator.
 Mounted below a Z28 turntable with manual rotation. Too large & does not open far enough. Looking for ideas to build a smaller more compact version. Had a Eureka moment and solution now found for a compact Clamshell Grab:- Clamshell 
Grab in closed position:- Clamshell Grab in open position:- 



Try picture frame hanging cord it’s braided and very strong. Have used 1mm diam.cord it with success on my various crane builds.

Thanks - here is a close up of the gearing at the hinge between the Main Boom & Dipper arm that allows dipper arm to be fully retracted. It might be un-conventional but it works well and the gears all mesh correctly. The 4 arm claw grab is a copy of the one used in the 42006 set.

Many thanks for your comments much appreciated. Awaiting parts on order for yellow panels to complete the bodywork, along with the elevating operators cabin.

 Dipper arm to extend by 15L and hope to to devise a simple way of changing various attachments i.e 4 arm claw, 2 bucket clam shell & maybe a demolition hammer. These versatile machines are also available mounted on crawler tracks, trucks, rails or fixed pedestals.

 So I intend to build a crawler under carriage using a pre-assembled subtractor module I already previously built for drive & steering. 
 The rotating body with booms etc. can be easily detached from the wheeled undercarriage and re-mounted onto crawlers tracks. Should be easier as no outriggers be required. The MOC is very stable when slewing both when on wheels or outriggers with boom & dipper arms fully extended.

 Sennebogen has a version with Vario-tools - see link, which includes a demolition hammer. https://www.sennebogen.com/en/products/material-handler/sennebogen-830/vario-tool-76.html

Dipper Arm and drive to 4 claw grab.

 Progress has been quite slow due to trying to find the best solution to preventing gear clash when dipper arm fully retracted at the hinge point on main boom. 
 Involved a lot of trial & error before came up with a workable solution.

 Devising the drive shafting to the dipper arm also a slow process with the “dreaded”: 1/2 L causing problems between U-joints.
 Dipper arm still needs extending so that the grab can reach the ground when main boom fully lowered. All functions tested and working OK plus whole unit slews very smoothly. 

 Some of the failed attempts at transmitting drive through the hinge point between the main boom & dipper arm. .

 Successful at last eliminating the gear clash but needs some tidying up.

 General views I will also be building a clam shell bucket attachment to be interchangeable with the 4 claw grab. For added complexity it could be made to rotate but would involve another drive path so probably will be manual. Elevating operating cabin, I could use a mini figure to turn a crank to operate it !!!

Looks good and like the way the balls drop into the collection hopper.

Andy thanks, This is the machine I am basing my MOC on and yes I do intend to have an elevating cabin.
 Its an interesting build with lots of problem solving !! 

 As the build progresses the boom was causing sag of each end of the base of rotating structure. Now that the side body panels are in place that is now fixed. Actuator and drive for dipper arm installed on main boom OK. 

Dipper arm:-
 This has a wide range of movement - almost 180 degs. swing up & down.
 The drive to the implement that will go on end of dipper arm is a new problem. 
 The normal way using a 20T bevel gear with pin hole & two 12T single bevel gears to put a drive though an articulated joint between the main boom & dipper arm doesn’t work. 
It locks up when the dipper arm linear actuator is fully retracted with an angle between dipper arm & main boom of 60 degs.
 The two 12T single bevel gears touch and lock. 
U-joints won’t work either due to the acute angle. I have found a solution with added bonus of a 20/12 reduction in the drive to the implement and now have to build it into the dipper arm.
 Angle between dipper arm & main boom now is 30 degs. before gears touch.

To start a new MOC I search on line & YouTube for a machine I intend to build, then download images and print out any plans / diagramed etc. to work out sizes. For wheeled MOCs I start with the tire size that looks best then scale up everything around that. For tracked MOCs I build a mock up of the track unit to determine the overall size.

Thanks for your comments - I tend to build something to determine that the geometry / layout will work in the the space available then refine it until its works and looks better. Slightly modified the actuator module since last image by repositioning the end support LEGO Technic Cross Block 1 x 3 (Axle/Pin/Axle) (32184) to give an extra 1L space to fit in the elevating cabin on left side.

Illegal beams removed !! Boom actuator module re-built and now much more rigid & cleaner looking. Moved module back 2L and braced to the motor cluster.. Now have to figure out where the operators cabin can fit, along with the elevating mechanism.

I did as well but it fits without any forcing when inserting pins, problem due to the afore mentioned flexing. Its a process of build evolution ! Anyway I,m going to change that part of the framing to 5L x 9L bent lift arm with 2 x 45 dregs.

Revised motor layout:
 M2 & M3 raised and M1 placed below them on centreline eliminating the four U-joints.
 M1 - L motor - boom actuator drive. 
M2 - Dipper arm actuator drive. 
M3 - Drive to 4 arm claw grab or clam shell buckets. 
Battery box added as counterweight. Main Boom Actuators module.
 Based on the geometry used for the 8043 Excavator. Some flexing when the two main boom actuators reach full travel both ways despite using a white 24T clutch gear.
 Slight forward sag due to boom weight even with using the 13M turntable system. Framing for base of rotating structure to stiffen.
 Doubt a standard Lego turntable would support the weight without a lot of droop ! 
 Support structure for the three actuators flexes, so a redesign required and probably move the module back by 1L or 2L. View of lower main boom, Showing drive to dipper arm actuator and claw grab.
 Boom to be extended by another 15L, and position linear actuator for the dipper arm.

Yes & used an L motor for M1 placed below M2 & M3. There is 11stud turntable version now which might suit the 42009 crane. Gear support ring
:- https://www.shapeways.com/product/WYQND3UBD/turntablesupport-11m?optionId=64700224&li=marketplace Wheel holders- https://www.shapeways.com/product/TBN9LW2WJ/wheelholder-for-turntablesupport-11m?optionId=64700240&li=marketplace

Thanks, got a long way to go yet ! I may have to rob parts from previous models to complete this build.

Support ring:- It's located by 8 pce. 3/4 pins as shown - ( poor lighting now daylight gone & energy saving light bulbs give a weird light when taking photos !) They only serve to locate the part, the weight above holds it in place and the X56 or Z60 turntable secures it down as well. They solve a lot of problems when building large MOCs. The 42009 Mobile crane problems could have done with a better turntable system. Re Motors:- I was trying to keep top of machinery housing low but considering raising by 1L remove the U-joints & use direct drive. The original layout was three M motors side by side which meant couldn't put an L motor in the centre due its bulge shape . Now that the two upper M motors (M2 & 3) are higher I can put the L motor below on centreline and still keep the the 8T / 24T clutch gear reduction. Doug

Thanks. Motors installed:- 
Four M motors used as most compact.
 M1:- Main boom raise & lower via 3:1 reduction and 24T clutch gear.
 M2:- Dipper arm raise & lower.
 M3:- Claw or twin bucket actuators
. M4: Slewing at 100:1 reduction. May change M1 to L motor later if need more power required to raise the boom. Battery box to install behind motors for balance. The linear actuators for the main boom and the drive up through boom are based on the 8043 Excavator. Arrangement of body panels still in progress. Elevating cabin to devise.

I brought two sets when Efferman first designed them and have used them in previous MOCs, i.e Level Luffinfg Dock Crane. That are very useful for MOCs that should use a larger turntable for stable slewing and reduce turning friction. They are ideal for my current MOC where a Z56 or Z60 turntable would not support the rotating structure very well - the turntable is only used to centre the 3D components. They are now available in 3 sizes: 11L / 13L / 17L, you can use two sets wheel supports or for heavy loads 4 sets. The wheels are Lego p/n 42610 LEGO Wheel Hub Ø11.2 x 8 with Centre Groove and held in place using 2L red axles. 3D parts are in white and I used a grey paint pen to colour them which is a close match with Lego light grey.

They are not Lego parts, they are 3D printed and were designed by Efferman and are available from Shapeways. https://www.shapeways.com/marketplace?type=product&q=efferman 13L studs size in white. https://www.shapeways.com/product/KGVVXXQ8Z/wheelholder-for-turntable-support?optionId=58698690&li=marketplace https://www.shapeways.com/product/CBJHXEZWV/turntable-support-13-studs-diameter?optionId=58697999&li=marketplace Also availabe in a larger siz of 17 studs. Turntable update:_ Unable to get good location points to lower the 13L turntable support gear ring by 1L without changing the undercarriage top deck. Therefore I have lowered side panels to hide the gap..

Non steered axle before: 

 Additional support added:
 Only added to underside to avoid having to take off top deck to modify the same.

 Turntable:
 Custom turntable modified by removing the two side three wheel supports.
 Centre turntable changed from Z56 to Z60 with has less friction, as it now only acts for centring the custom turntable.
 The remaining wheel supports more than adequate for fore & aft forces. Slewing is by a an 8T gear messing with 13L gear ring internal teeth.
 M motor with 8:1 reduction (worm / 8T gear) to give overall reduction of 100:1 for good slewing speed, not too fast & not too slow.

Thanks - I take your point but not experiencing any bowing of the wheel axles. I wanted to replicate the double tires as per the machine I am basing my MOC on. The steered axle support is much closer to the inner tire, the other axle is performing OK without any bow or sag. I was unable to devise support further out along the axle inside the wheel hub reccess. Also have re-configured the turntable. I post some pictures later.

Turntable:- Z56 turntable used as better for arranging the slewing gearing - the Z60 T/T is not so easy.
 This turntable on its own is not enough to support the rotating structure without very careful balancing andh has lot of friction when slewing due to the weight above it.
 Therefore I will be using the Efferman designed 13L turntable gear ring and support rollers which take the weight of the Z56 T/T and provides much more stable support for the rotating structure. 
I used this on my previous level luffing crane build with great success and fully supports any structure above it. A Z56 turntable still used but only to centre everything and provide for slewing. 13L support gear ring.
Attached at eight locations in 4 groups of 2.
 Effereman Turntable unit.
 The 3D white parts have been coloured light grey using a paint pen.
 Mock up of side panels:
 Elevating cabin will be to the left of the taper panel. As shown the rotating structure is too high above the undercarriage and I need to lower the 13L gear by 1L. 
This will mean finding new mounting points for the 13L gear ring onto the undercarriage top deck.

You need to ensure the part with 3 pins is pushed into the portal unit firmly until it clicks home it needs a bit of force to do this. Once firmly in place it should then be quite difficult to remove again. if it still comes out then part probably damaged.

Would the inclined GBC lift shown in this video be suitable ? It uses a M motor powered change over unit and elastic cord to move the trolley which allows the cord to run when car hits stops until c/o unit reverses the drive cord drum. Does not need any PF c/o switches as its purely mecahical.