doug72

Try Goo Gone by Magic American Products

Thanks for your comments. The main problem has been getting the turntable revolving smoothly as there is a lot balanced on top of it and no room to use a wider base. Tried both the new Z60 & old Z56 turntables each of which have their own quirks and raising the revolving structure above the slewing gear ring but finally after a lot of experimenting kept to the Z60 TT.

Final tweaking of my tower crane MOC before posting on Entry Topic once the video re-shot. Slewing problem resolved whereby the 12T double bevel gear driving the turntable was catching on the corners of the winding house base 5 x 7 frame as it rotated, causing jerky rotation. No Lego parts were harmed during this modification. Its all in the balance of the rotating structure. The slewing drive to the turntable has reverted to a straight drive using a short UJ section to give 1-1/2 L spacing to get 12T gear correctly meshed with turntable gear ring without off-set. IMG_2676 by Doug Ridgway, on Flickr

I enjoyed build this mobile crane and later modifying it to the Ultimate version with 8 PF motors. Crane now dismantled in order to utilise the parts and motors for the crane contest. I also much prefer building cranes to building a succesion of front end loaders. Cranes offer much more variety with some very unusual examples making them a good challenge when building them using Lego Technic without modification of any parts. Lego should re-issue the metal crane hook as a spare part.

More solid but prone to racking or twisting along its length. A triangular shape resists this. The whole jib is a series of triangles. Also the jib is lighter as there is one less corner beam to make and allows for lifting a slightly heavier load on the hook. The key is getting the top rib of the jib that forms the apex of the triangular cross section in tension with good connections between the main 15L beams. Simple 2L connections are not enough - 4L thin plates are used with 2L red axles at each end through the X holes with two half pins with stud used in the plain holes (One pushed in form each side to connect with the 15L beams) making it a 4 pin connection. The protruding stud allows for 4L x 1L flat plate with "Technic" to cover the connection. (not shown in photo) The angle braces between lower & upper beams again form triangles making it strong, light and straight. Could be lighter if 9L thin liftarms were available. Old square jib now consigned to my parts boxes forother projects.

Triangular it is - thanks for the comments. My MOC of a horizontal jib tower crane uses a version of this design of jib with track for the hoist trolley.

The real tower crane my MOC is based on has a jib with a triangular cross section. At present my MOC has a square cross section jib. I have now made a new jib to try and replicate a triangular cross section jib but cannot make my mind up which is the best jib to use. I have also managed to eliminate the two gray "I" frames from the jib structure. Your opinions appreciated. Square Cross section jib: IMG_2667 by Doug Ridgway, on Flickr Triangular cross section jib IMG_2666 by Doug Ridgway, on Flickr

This is my first contest and its been an interesting build time - constantly trying to improve my TC 8 entry to make it reliable with the limited number of parts I have to hand plus a few extra parts ordered. It has been a rewarding challenge. I had to dismantle my 42009 ulitmate crane to get enough parts and PF motors to build the luffing jib tower crane entry. My TC8 is my 2nd large crane build. 1st was my Giant Block Setting Crane and the 3rd was a horizontal jib tower crane built from what I learned from building the TC 8 entry. Already planning future crane builds - going back to the days when I used Meccanno to build them. Possible a Coles portable yard crane from 1950's. This is unusualal in that it has a triangular wheel base with the rear 2 wheels having caster steering.

Happy Birthday and thanks for a great model. Currently building it and up to step 21. Is it possible to add the L length of beams where the parts for each stage / step are shown on the instructions ?

Jib luffing system improved and side panels altered to suit new arrangment. The model is now complete. IMG_2653 by Doug Ridgway, on Flickr

A winner in each catorgary

Perhaps the contest should have been spilt into two sections for mobile cranes and static cranes.

Operators cab now rebuilt and located on the correct side of the Terex Crane !! Floodlights (non working) also added. Curved front idea didn't work as could not get a proper connection. IMG_2626 by Doug Ridgway, on Flickr

Thanks for your comment and suggestion - I will see if I can support to cabin further forward and lower. Re Technic Cabin: at the scale I'm using (Minifig) use of Studdless Technic parts I feel would be too chunky. Aso I like the angle glazed front similar to a real cabin. Have a Lego Train part with a curved front that may suit. Doug72

Update: Mechanics of my crane build now finally sorted with all functions running smoothly. Slewing gear driving the turntable is back to the offset position with the two UJ’s located near base of the tower. Winding house and operators cabin now all in yellow with stickers applied. Not sure wether to clad the counterweight in yellow - I have the right colour sticky back plastic film to do this. One thing I find awkward is mating studded technic with studless technic due to the different spacings. I have endeavoured to hide the holes in the technic beams where possible using flat plates and tiles. Next step - make a new video. Two photos show the results IMG_2621 by Doug Ridgway, on Flickr IMG_2621 by Doug Ridgway, on Flickr IMG_2622 by Doug Ridgway, on Flickr

Great - can now finish the details on my crane & make the entry video.

Is it permissible to use stickers from other Lego sets ? eg. UW Lifting service from the 42009 set.

An impossible technic build ! or is it ? Curved telescopic extending jib

I have always wanted to make a Liebherr 550 mobile harbour crane - several are at work near me at the Port of Tyne and I watch the progress of one being built at the Liebherr factory in Sunderland when I am out cycling the banks of the R. Wear. Quickly realised it would be a task beyond me. Especially trying to make the tower and the multiple individual steered wheel units. So settled for a simpler build for TC8

I have used small"o" rings with success on broken UJ,s "O"ring size:- - 1mm x 8mm o.d. x 4mm i.d

Thanks for that tip - now tried it on my TC8 crane and working well - universal joints are located at base of tower and then direct drive up the slewing 12T gear. Even managed to get a support for the angled shaft between the two UJ's. Much tider looking solution.

Thanks for that info. Forgotten about that !! Have changed back to a Z56 T/T for the tower crane and just changed the slewing drive for my TC8 Luffing Jib Tower Crane (with Z60 T/T) to a straight drive and now both slewing smoothly. Will try your suggestion just to see if it does make a difference.

Update: Due on going niggling problems with slewing smoothly I have raised the rope winding house by 1L above the rotating part of the turntable. This ensures the slewing 12T bevel gear does not rub on the underside framing of the winding house as it rotates. A driving ring extension cone was required due 1L change to keep all the co-axial gearing in mesh OK at the top of the tower. This meant a complete strip down of the winding house and rebuild making it 1L higher above the T/T, it also made it 1L longer. Universal coulplings eliminated but with 12T gear for slewing still offset. The drive shaft now runs directly up the side of the tower and uses three 8T gears at the base to transfer the output from reduction gearing. Found also that the white 24T clutch gear was slipping so this replaced with a plain 24T gear. Photo shows new gearing:- note- yellow beams swung clear for clearer image. IMG_2614 by Doug Ridgway, on Flickr Now rotating smoothly with jib at different positions. One thing I have learnt during this build is that everything has to be well braced and supported. Now have to make a new video for the contest entry.

I was not really happy with the rotation of this crane due to erractic rotation when slewing the crane jib using an offset drive via universal couplings to the 12T bevel gear meshing with the Z60 turntable. The erratic motion is caused I think is due to the universal couplings. The alternative suggestion for a straight run using bevel gears has to much friction. I have therefore reverted to using a Z56 turntable. The Z56 turntable allows a straight run for the drive shaft up the side of the tower and use of a 8T gear to mesh with turntable ring. Overall gear ratio for rotation now 168:1 Photo shows set up on my TC8 Luffing jib tower crane IMG_2577 by Doug Ridgway, on Flickr

Hoist Trolley traversing system: During the tower crane build I could not find a suitable drive pulley that fitted the space available and still be Lego legal, so I modified p/n 13971 18 x 7 narrow rim by drilling the pin hole to accept half axle bushes which bonded in. ( Shown on left side of photo) I had several 55981 wheel hubs 18 x 14 - which have two grooves but have a plain pin hole - so also not suitable as a drive pulley. Finally found I had one 55982 wheel hub which has a axle hole and two grooves. (on right of photo) IMG_2608 by Doug Ridgway, on Flickr Crane now fitted with legal parts as shown and 24T clutch gear replaced by a normal 24T gear. IMG_2609 by Doug Ridgway, on Flickr So how does it work - the secret is 2mm braided elastic cord. The groove in the 55982 wheel has enough friction to drive the cord and hence the hoist trolley. Correct tension has to be found by trial & error and adjusted at the hoist trolley. When trolley reaches each end of travel the cord stretches until it slips or drive stopped. Effective without use of double drums or cords getting tangled due to uneven winding of cord onto the drums.