[MOC REVIEW] Grove GMK6400 Mobile Crane

[maverick14]

Hello,

Based on Alex's MK3 .mpd file I have created a BSX inventory file that I think should take everyone 99.9% there. The only missing things are the Firgelli actuators and the NXT to PF cables but, I guess if you are reading this thread, you know you need those for this version of the build

In total BrickStock, reports 3600 items in 253 lots. I would appreciate if Alex or someone else who has done the build could have a look at the file shared below and validate it.

http://bricksafe.com/files/maverick/GMK6400/GMK6400-Mk3_Firgelli.bsx

Thanks

Alex C

[ferindel]

Hi,

Based on Alex's MK3 .mpd file I have created a BSX inventory file that I think should take everyone 99.9% there. The only missing things are the Firgelli actuators and the NXT to PF cables but, I guess if you are reading this thread, you know you need those for this version of the build

Thank you, Alex C

Edited May 21, 2015 by ferindel

[bonox]

by request - superstructure option #4 with third party actuator and 100t counterweight

[ferindel]

Hi Alex C,

Based on Alex's MK3 .mpd file I have created a BSX inventory file that I think should take everyone 99.9% there. The only missing things are the Firgelli actuators and the NXT to PF cables but, I guess if you are reading this thread, you know you need those for this version of the build

In total BrickStock, reports 3600 items in 253 lots. I would appreciate if Alex or someone else who has done the build could have a look at the file shared below and validate it.

I have not built it (yet), but according to the instructions provided by Alex, I can already say that the two cords are missing in your BSX inventory file

I have the time and motivation to check your BSX file with the instruction file next week, so I'll check if other parts are missing or not.

Regarding the NXT to PF cables, I just want to say that they are no longer available from Firgelli or from the other website provided by Alex in his instructions. I contacted Firgelli to get information, as these cables were out of stock everywhere, and I was told that these cables will never be available again as Lego stopped selling them the parts needed to make the cables. For those who need these cables for the Firgelli actuators, the only way to get them is to make them by yourself. For that, you need a connector cable for Mindstorms NXT of 35 cm (part #55805) and a power functions extension cable (part #60656, as I think that a length of 20 cm is ok). The instructions to get 2 NXT to PF cables from these 2 are given there: http://www.legomindstormsrobots.com/lego-minstorms/lego-pf-to-nxt-cable/.

ferindel

[efferman]

bonox, nice to see it finished. how is the balance of the uppercarriage with the large counterweight? and how much is the weight of the counterweight with batterys in the boxes??

Edited May 24, 2015 by efferman

[bonox]

hi Efferman

It balances very nicely at about 30-60 degree boom elevation with counterweight installed without batteries or a lifted load and no boom extension. It's very sensitive to boom extension and load, less so to elevation unless you're around zero or 70 degrees. Although not shown, I have your twin reel metal hook on it and it fits the scale very nicely. I'm very happy with your upper design, so thankyou very much again for publishing it.

The counterweight is 650grammes without batteries, about a kilogramme with all twelve.

[efferman]

thank you very much.

how is the weight of the hook?

Edited May 24, 2015 by efferman

[bonox]

my scales don't really measure that low very well, but it certainly has more heft to it than the original lego version.

I will say that it's on the cusp of being heavy enough to drop freely when using two of the hole centre pulleys you also produce for it. If you used two ordinary axle centred pulleys, it's not really heavy enough to get enough slip of the string to make the thing fall under its own weight. I'd roughly estimate it at about 50 grammes.

I got the bronze version too, not the steel.

[ferindel]

Hi Alex C,

I checked your BSX file and compared it with the part lists provided in Alex's instructions. Totally, if I'm not mistaking, there are only 3 mistakes (out of the 255 lots, so very good job):

1. there are only 14 + 6 = 20 black technic axles 4, and not 22;
   
2. like I said earlier, the two 250 cm medium thickness cords are missing (I don't know what the length of the cords Alex used is, so I just considered that it is the same cord as the one used for the 42009... anyway, better have a long cord that you can cut if necessary, as it's more difficult to make a short cord longer);
   
3. finally, you also forgot 2 tan technic axles 4.
   

Here is the modified BSX file: http://bricksafe.com...gelli_modif.bsx.

Of course, like you said, the 2 Firgelli linear actuators as well as the 2 NXT to PF cables need to be added to this list.

Besides, here is the parts list after removing all the parts of the 42009 set: http://www.bricksafe.com/files/ferindel/GMK6400-Mk3_Firgelli_modif_without_42009.bsx. If I haven't made any mistake, anyone already having the 42009 should get 1458 items in 183 lots.

ferindel

Edited May 26, 2015 by ferindel

[maverick14]

Hi ferindel,

Thank you for taking the time to validate! I had a feeling there will be a couple of items missing and it is good to know that someone else has gone through it.

Cord wise, I am not sure what the guys that have built this monster already have done about it but, most likely, I will be using a 3rd party one. Thinking very hard about using a textile fishing line which has a clearly rated capacity. I am actually planning to lift a good amount of weight with this crane...

I have done the subtraction of 42009 from the total myself but I will need to make it home in order to check the numbers. It looks to be in the ballpark though!

PS: my Firgellis shipped today

cheers

Alex C

[ferindel]

Hi Alex C,

Thank you for taking the time to validate! I had a feeling there will be a couple of items missing and it is good to know that someone else has gone through it.

No problem at all. However, I cannot guarantee that I didn't make any mistake either

Cord wise, I am not sure what the guys that have built this monster already have done about it but, most likely, I will be using a 3rd party one. Thinking very hard about using a textile fishing line which has a clearly rated capacity. I am actually planning to lift a good amount of weight with this crane...

I have done the subtraction of 42009 from the total myself but I will need to make it home in order to check the numbers. It looks to be in the ballpark though!

PS: my Firgellis shipped today

Mine shipped yesterday with the modified gearing

[maverick14]

Mine shipped yesterday with the modified gearing

Got that too! Hopefully the NXT-to-PF cables from Robotshop make it here as well!

finally, you also forgot 2 tan technic axles 4.

ferindel

Alex, I was wondering why for the first drive assembly these 2 tan technic axles 4 were used instead of the tan axle 4 with center stop like for the rest of the drive assemblies?

[bonox]

if you read further up you'll find the designers comment on why that axle type was chosen

[maverick14]

Thanks! - For anyone interested see posts #428 and #436.

On a related note, Bricklink does not list any Tan Axle 4 lots for sale... are they that rare? I guess using a regular black one would not have any negative side effects except for esthetics.

Edited May 27, 2015 by maverick14

[ferindel]

Hi,

I was wondering whether it was really useful or not to get two 42009 mobile cranes to build the Grove MKIII. I hence made a comparison:

• with one 42009 mobile crane, as said earlier, 1458 items are required in 183 lots, for an average cost of $631,065 (according to brickstock);
  
• with two 42009 mobile cranes, 807 items are required in 139 lots, for an average cost of $510,408 (once again, according to brickstock).
  

Getting 2 mobiles cranes hence allows to save 651 items and an average cost of more or less $120 (but you have to pay the second 42009, of course). As a 42009 mobile crane contains 2606 parts, it means that, at the end, you'll have paid an average cost of $631,065 for all the parts you need, but it also means that you'll get 1955 parts which can be used for other MOCs for a price which equals the price of a 42009 mobile crane minus $120. As a consequence, this can be interesting for people who want to get spare parts at quite a reasonable price, I think.

ferindel

P.S.: I can provide the updated parts list if some people are interested.

Edited May 27, 2015 by ferindel

[nerdsforprez]

Has anyone considered the following as an actuator for this project? I will not be building the GMK6400, I have my own model that I have built, but am considering buying this bad boy and revamping my crane in the process. If someone has used this actuator before, I am curious to any feedback. As can be seen, it is quite pricey.

https://www.bricklin...Eezo&viewCart=Y

[Blakbird]

Has anyone considered the following as an actuator for this project? I will not be building the GMK6400, I have my own model that I have built, but am considering buying this bad boy and revamping my crane in the process. If someone has used this actuator before, I am curious to any feedback. As can be seen, it is quite pricey.

This actuator was discussed earlier in the thread. It costs a lot, but about the same as Efferman's actuator. The disadvatage is that the motor hangs of the back rather than being geared to the input, and there is no bracket to mount the actuator. It is effectively trunnion mounted on screws at the base of the unit so the motor would swing through space. This means it would be much harder to integrate into a superstructure.

[nerdsforprez]

Gotcha.... thanx. Looks like I will not be buying it. I should read the whole post, but that is the problem with posts this long. I have not been following everyday (or every week) and sometimes by the time a get around to seeing it again it has changed so much and I don't have the time to get caught up on all that has transpired......

[maverick14]

Hi Nerdsforprez,

looking at your pictures I noticed that you have a realistic looking wiring setup of the hook (multiple pulleys/wires vs only 1). Would you mind posting a shot that shows better that area of the build?

Thanks

Alex C

[FalconEquipment]

Looks great, nice work!

[grum64]

Hi Nerdsforprez,

looking at your pictures I noticed that you have a realistic looking wiring setup of the hook (multiple pulleys/wires vs only 1). Would you mind posting a shot that shows better that area of the build?

Thanks

Alex C

I'd be interested in seeing this also. It looks so much better.

[nerdsforprez]

Sorry guys...... just getting around to seeing this.. what exactly would you like additional pictures of? I can try to get the pics when I get home, but to be honest with you it may take a while. I am in the process of moving my family in the next month and therefore we are slowly packing bit by bit. Although I have not yet packed by LEGO models my cranes cables (string) came undone when I had to move it from my office. I can re-string it... but it takes time. I will say this..... in one aspect I used modified parts. The pulley system only works if the pulleys are bored all the way through.... (no axle hole). This allows the pulleys to move at different speeds and therefore leads to the enhanced lifting power. So I bored the Technic wedges

http://www.bricklink.com/search.asp?colorID=1&itemID=823

with a drill. I know Efferman offers these pieces (bored hole) on Shapeways but I thought I would just make the part myself. I did this to mimic real cranes, and tried to lift a modified 8070 at around 1300 grams. Even with the pulley system it did not work.

One of my first projects after I move will be to couple two L-PF motors together to increase the lifting power and fit them into the superstructure. I want the crane to lift the 8070!!! I will post it when it is all done but probably will take a while. Lemme know what pics you want and I will try to get them.

Edited June 11, 2015 by nerdsforprez

[efferman]

which gear ratio ands motor do you have in the winch?

btw, i think you have made a error in the Y-stabilizers. why do you have the liftarms on the extension side where dou you have to change the liftarms at every retracting and extracting the boom?

source

[nerdsforprez]

I did this only for the purpose of the lift of 8070. I get that they are supposed to be switched..... however, I was not lifting the boom any and for the purpose of the lift needed the top part more stable than any other part of the bottom part. It is corrected when I present the model.... but again, only for the purpose of the lift I switched them.......

[MaxSupercars]

by request - superstructure option #4 with third party actuator and 100t counterweight

Is it Actuator from Efferman?

Max