doug72

Thanks for your comments and support during this build. My first BWE became a BWT. Don't think another way will come my way. Only comparison is by using th Lego Box graphics.

MOC completed. Time to allow the dining table to revert to its proper use. It has been a protracted build with many problems along the way which were eventually resolved by trial & error but finally got it to function as I had envisaged. Operators cab, ladders, guard rails & mini figures now added. If I were to build this again:- I would modify the under carriage keeping the track units and XL motor drives but build in a large battery box plus a double layer of BWE gear quadrants to give better clearance for slewing drive gear and provide a stronger base. If I have enough parts left over I will probably try this. I would build the rotating upper structure to be stronger and less susceptible to bending under flexing when bucket ladders is in operating position and get a better balance. I am happy with the ball unloading system via top discharge and is working well. Only thing left to do is arrange a ball loading hopper so each bucket can scoop up two balls at a time as it rotates around the chain return sprocket. Final step is to put up a strong shelf in my study to display it.

Gabi, Thanks Here's a short video showing how the balls are unloaded, just needs a bit more fine tuning to stop balls escaping.

It's a smashing video !

Details of how buckets are attachment to chain. The centre yellow part separates the bucket to prevent balls getting trapped and ensure they roll off at the sides of the bucket. Turntable Ring gear: If I re-built this MOC I would recommend using two stacked layers of gear quadrants to bear the heavy weight and stiffen up the rotating structure. This allows you to eliminate the four LEGO Black Technic Cross Block 2 x 2 x 2 Bent 90 Split (Pin/Twin Axle) (92907) to provide a wider track for the support wheels to roll along without fouling. Lower gear ring attached using pin holes same as before. Edit: For maximum stiffness overlap the joints between upper and lower gear rings. Only downside is the gear teeth between the two layers don’t align but the slewing gear can still engage with the upper gear ring OK and have plenty of clearance over the supporting structure & the battery box below.

Thanks, I have yet to start the aesthetics. At the moment I am having a big tidy up getting all the many loose unused parts back in their storage boxes, bins. Operators cabin next, then machinery housing ( to hide counterweights) and ladders and handrails. Re buckets, no cutting, only modified using only Lego parts to divide into two compartments. Ball discharge is now working over the top OK once I got the ball guides aligned properly to direct them down onto the chute below. Have an idea for a ball loading hopper and once proven & reliable will post a video. Tested the tracks and it crawls nice and slowly, and can make easy turns if use a train controller. Estimate over 4000 parts used !!

“The Mega Machine Awakes” At long last got to the stage where its all coming together - video now made showing the slewing, raising & lowering of the bucket ladder and the bucket chain in motion. Bucket chain is 108 links in length with nine buckets. Bucket discharge over the top is feasible. Had to raise the drive sprocket and re-position the L motor worm drive gearbox to achieve this. This gave more room to better position the ball collection chute. Almost there adjusting the guides to ensure balls after falling out of the bucket drop onto the chute below. Balls are loaded by hand at the moment but will devise a way for buckets to scoop them up. The rotating structure has to be well balance to ensure it rides well on the turntable gear quadrants. Clearance over the battery box in the lower structure is very tight. The whole machine is quite heavy and and is built on a modified BWE base and if I built it again I would make a stronger more rigid structure. Bucket ladder can be positioned from 45 degs. up to 45 degs. down while chain is moving. M motor for hoisting system moved higher up the structure to avoid need for for an extension cable, the 6 fold pulley system to raise & lower the bucket ladder is adequate. Enjoy the video which made using a hand held compact camera. As per the actual machine its noisy ! Another video will be later made to show the machine travel and steering

Slewing problem resolved:- Tried changing the wedge wheels to disc wheel with treaded tires but found the sides were catching on the gear quadrant connectors at four points when slewing. Reverted to wedge wheels again but double up, i.e. 2 per axle at three locations. The 4th location with the rubber tire wheel required for the discharge conveyor positioning system was changed to a smooth tire which does not catch on the gear quadrant connectors. Still had problem it as it would not slew 360 degs. due to the 12T double bevel gear losing engagement with the gear quadrant teeth at one point. Finally found that due to where I had positioned the PF Rx for the caterpillar track drive. The BWE way of securing the gear quadrant at that point to the under carriage could not be used. Results was that under load the gear two quadrant at that point flexed outwards enough to disengage the 12T gear. Now fixed securely by an alternative method with pins and axles to prevent flexing movement. Slewing tested extensively today with bucket chain in place and has shown rotating structure has to be well balanced. At present slewing by M motor has is 20:1 x 140:12 - overall approx 233:1 and is a bit little fast. Can slow this by adding a 12:20 gears in right angle drive from M motor to give approx 388:1 reduction. Three full battery boxes are required to counter balance the bucket ladder. Slewing / hoisting / travel all functioning correctly, just some minor fine tuning to sort and tidying up PF cables runs, add operators cabin, handrails, ladders etc. Hope to post videos in next few days showing each function. Possible improved ball unloading from buckets:- Whilst further testing I noticed that occasionally balls did not roll out of the bucket from the front edge but still ended up on the discharge conveyor ! Discovered they had exited the bucket AFTER the bucket had passed around the drive sprocket. As each bucket after passing around the drive sprocket and starts its decent the balls roll out of the back of the bucket into the gap between edge of the bucket chain and the housing before dropping down on the collecting chute above the discharge conveyor. If this proves workable it will negate the need to bend the bucket chain backwards as much and should make the bucket chain motion less jerky & much smoother. The new way of attaching the buckets to the chain is the secret and along with a small addition to the chain fixings by dividing the bucket into two sides the balls can fall off from each side. Collecting chute will need slightly extending to catch the balls. I will modify 4 buckets to test and prove this discovery. Doug. The bucket ladder is being held up by the hoist ropes which are WHITE hence invisble on the white background !!!

Be awhile as have had a bit of a set back. The bucket ladder is quite heavy and is tipping the structure forward when held up by hoist rope. The wedge wheels used on the BWE design that roll along the edge of gear quadrants are not up to the job and keep slipping off, causing the slewing to jam. Substituting the wedge wheels with disc wheels with tires that have more contact on the gear quadrant (same as used under the conveyor) which should help stop the tipping forward. Also working out the counterweight needed to balance every thing better when the bucket ladder in place. Slewing & hoisting motors now re-positioned and PF switch and PF Rx installed.

I'll keep this for awhile but eventually it will be broken down to build something else. Its been a useful exercise in problem solving. Motors for hoisting & slewing now re-positioned higher up.

Thanks for the comments. There were times when I thought it was impossible to build without resorting to 3rd party or 3D printing but have managed to build it using 99.99% Lego legal parts - just the hoisting cord which s 3rd party because the Lego cord I have is too short. Looks like I will have to shift the position of the two M motors for slewing & hoisting higher up in the side frames to be able to connect them to the PF Rx without using extension cables. Main problem after I finish building it is where to display / store it ! Its 90 cm length x 40 cm high x 30cm wide and no idea how many parts used. I will probably make seperate videos showing each function, i.e. travel, slewing, hoisting, digging, as i only have a hand held compact camera to take them.

I'l keep the chain drive gearing as it is as it would be quite a task to rebuild for a different ratio due space constrainsts. Just tried the bucket ladder at 45 degs upwards and runs OK but no way would balls stay in the buckets !!!! The upper run of the chain dips down to the hinge point & bends back up again without any problem. Due to the increased chain slack when 45 deg up, each bucket as it goes around the return sprocket drops slightly before entering the guide rails. The shock absorber chain tensioners only has about 1.5L travel and just right for when bucket ladder is 45 deg. down.

Batteries might be running out from the many tests runs. Edit: Batteries now changed and speed much better. Also lowered by 1L the top return rollers and changed the 3L guide beams to a 1L beam + an 11.2 Wheel hub giving a better guide geometry for the chain with less shaking. Present gear ratio is 24:1 using older worm & L motor. Now I have the newer worm gears could try 20:1 ratio but will have to design a new gearbox.

Bucket ladder video: NEW Tested and working OK. After individually checking every single track tread in my possesion including from previous models, MOCs & GBCs I found had enough of the old links for the bucket chain. Needed these as they can bend "backwards" more than the newer type. Nine buckets are now fitted and evenly spaced on the chain Just some minor fine tuning tidy up some connections and try to eliminate the jerkyness and, which is caused as the back of each track link on the "bent backwards" section, as they pass over the ends of the guide rails. Guide support at bending point only 3L long (might try a 2L or 1L ) - pity curved beams not available. Can't use rollers as would foul the buckets as they pass. Upper support rollers added to keep top part of chain run from rubbing on the lower chain run where they are close together. Works OK when bucket ladder horizontal but some angle down is required when operating to keep balls in the buckets. Had to raise the drive sprocket in order to get enough space for a ball collection chute which still to be install. Video shows the bucket ladder and almost its lowest angle. Awaiting longer cord to use for the hoisting system. Next step, install PF receivers, operators cabin, machinery house and ladders / guide handrails etc.

Sariels Guide book has information on how to use this and recommends its use for fast vehicles. Also shows on page 223 - 2nd. edition how to mount on the front of an M motor using 4 x 2L x 0.5 plates with axle holes.

Answers: Cannot find any listed NO None yet. Solution: In order to comply with Lego Purists and be Lego Legal I have devised a new way of connecting each bucket to the bucket chain that eliminates to 5L x 0.5 spacer. Also is much better at guiding each bucket along the guide rails. The 5L x 0.5 spacer tended to snag around tight turns. IMG_4592 by Doug Ridgway, on Flickr IMG_4593 by Doug Ridgway, on Flickr

Yes if you are OK with left / centre / right. You just need a dab hand with remote to control direction. It mounts on the front of any PF motor OK.

You could try one of these: http://www.brickowl.com/catalog/lego-technic-axle-joiner-rectangular-with-spring Using a normal motor it has spring return to centre.

Update: Getting very close to perfecting the bucket chain path through the discharge housing so that the balls unload from each bucket at the front. It has taken a lot of trial builds / test / failure / start again but I finally think it is possible without any modification required to the buckets. BUT I HAVE A PROBLEM: The way each bucket is attached to the chain uses 2 x Pin w/ hole connectors with a 5L x 0.3L beam as a spacer. to ensure a tight connection to the track link. The ends of the spacers snag on the start of the various beams use to guide the chain along the ladder and up into the discharge housing especially where the chain bends backwards. What is required is a 3L x 0.5 beam which has three holes instead of XOX which will still guide the bucket along the guide rails but not snag. Did a test mod on one spacer and works as well, the bucket rises up from the ladder into the discharge housing high enough to clear everything and just before reaches the drive sprocket the chain dips allowing bucket to tip forward and discharge balls. Tested with both old and newer style large track treads and works OK. There is finally enough clearance for a short guide chute to drop balls onto the discharge conveyor. Hope this all makes sense. Question: Are 3L x 0.5 beam available with OOO configuration. ? Should I modify and cut down 5L x 0.5L beams to give 3L x 0.5. Has anyone other ideas of providing a Lego legal spacer 3L wide x 0.5 for the Pin with hole connectors. Bucket Ladder: Now rebuilt longer with a tensioning device for the return spocket wheel. This allows the chain to keep in contact with the return sprocket wheel at all positions between horizontal and 45 degs down. As a resuly the braided cord I have is too short ! More on order from eBay.

Thanks for that explanation - I shall have to hunt through my Lego to see if have enough parts or come up with another solution to the problem.

Re LEGO Large Tread Link (57518 / 88323 / 89501) As part of the BCE build of my I need a short section of bucket chain to bend for approx 60 degs the other way to normal. My first attempt used the grey large track links from the BWE set and it proved impossible to bend it as much as I required.Then tried the black large tread links and found they can bend backwards to a smaller diameter. Not sure if this is due to wear or not, anyone else noticed this. I have seen several GBC that use these links in this manner. Both tread link types shown in photo are bent backwards as far as possible without straining them.

A very interesting discussion topic. I have used 3D printed parts in the past to achieve a MOC due to space constraints but with the advent of new Lego parts i.e connectors, the new worm gear, large gear rack quadrant, it is now possible to build them using Lego parts only. One thing I would love Lego to have is more curved parts such as beams & quadrants. I am attempting with my current build of a BCE to use only Lego parts but this leaves a conundrum: End result is not functional or if modify a part it can be fully functional. At the moment I intend to explore every possibility to keep the BCE MOC 100% Lego and get it working. I have been to several Meccano exhibitions and even the most die hard Meccano builders sometimes use 3rd. party or modified parts. I like the challenge of using only Lego parts as it keeps the brain active !! Doug

Discharge conveyor now working as per BWE ie. Lock / unlock, manual with drive fom M motor now installed. Now re-designed the discharge housing similar to the MAN TAKRAF machine. Bucket ladder shown in position but not yet connected. Next is figure out the bucket chain run, I hope to keep the tip forward to discharge balls but if not possible then may have to modify the buckets.

Question s for Lego: 1/. Has Lego ever taken inspiration from Technic MOCs ? 2/. Would Lego consider developing a range of small GBC modules that could be linked to form larger set ups. ? Doug

Thanks, yes it way to high at the moment. Just have to sort out position of the discharge conveyor drive motor, then I will attempt to lower the bucket ladder as per the Man takraf machine. Problably have to re-design the discharge housing.