[MOC REVIEW] Grove GMK6400 Mobile Crane

[sbonas]

That’s true and it works with the standard cab, however I was thinking more of the excellent cab with the tilting operator cab I’ve spent hours trying to adapt that with the xl motor but it requires I believe a total redesign extending the other gearing further back and then that defeats me.  Also the connection with the superstructure is a major weak spot 

[myvideo000]

I decided to dismantle my heavily modded 42009 (mostly the ideas of jb70 and some of my own) and replace it by the Grove GMK. Since I want to use the new large actuators and no suspension, I have some questions:

1) Is it possible to use the superstructure from v1.1.7 and the carrier from v1.2?

2) Accoding to rebrickable I need at least 500cm string, but there are two different strings, a very long one for the hook (probably page 87 or 129 of v1.2) and a shorter one to connect sections 1 and 3 of the boom (page 116 of v1.2). Which kind of string is usefull? How long must and how thick may the two strings be? 

3) To begin with, I will use the old IR control. Has anybody built the Grove with two buwizz? I am quite sure they would fit and would improve the look espeacially on the carrier.

Thanks for the answers :-).

[Jasseji]

Hello, i have looked over your instructions and tried to build the boom as well, what i dont understand however, how is the 3rd sections upposed to be driven ? if i fix the string on the last hole of Section 3 and then pull it through to section 3, there is no "drive" there to move it

 

Am i stupid or blind, i dont see how it should work ;)

[myvideo000]

They use a string, see page 122 following in v1.1.7. Extension works in my version quite well, retraction doesn't without help. Detailled photos you can find here:

https://www.eurobricks.com/forum/index.php?/forums/topic/88549-42009-extended-boom/

[Jasseji]

15 hours ago, myvideo000 said:

They use a string, see page 122 following in v1.1.7. Extension works in my version quite well, retraction doesn't without help. Detailled photos you can find here:

https://www.eurobricks.com/forum/index.php?/forums/topic/88549-42009-extended-boom/

Sorry, i am indeed blind and braindead - i actually figured it out when looking closer at the pic ;)

[justhavingfun]

Could anybody direct me to the site that has the instructions for IR remote control.

Thanks.

[bonox]

i'm not sure there are any - they were incorporated into the instructions for sets that included them, so try looking for those. It's essentially make sure the transmitter is assigned the same channel (from 1 to 4) as the receiver you're trying to control, then move the controls. If you want it to keep going, or want graduated speed control, use the train controller.

[DizzelHondo]

https://share.icloud.com/photos/0ac7P5e2GMsEJEIeXoUYjrhKQ
 

I have started on the gmk6400 with no suspension.  It’s becoming quite a beast!  Building the @effermansuperstructure and going to use his xl actuator.  Would it be possible to make it out of aluminum?

 

 

[efferman]

2 hours ago, DizzelHondo said:

Would it be possible to make it out of aluminum?

maybe, but i guess it would need a pro in aluminium manufacturing.

[DizzelHondo]

10 minutes ago, efferman said:

maybe, but i guess it would need a pro in aluminium manufacturing.

I have a close friend that is CNC machinist and has a 3D printer. Would you be willing to send me your design? - I would pay you for it. 

[MatthewPChoy]

Beautifl model, where are the latest PDF instructions?

[nerdsforprez]

I have enjoyed watching folks’ builds of this crane.   Probably the most extensive and collaborative project we have here in this forum. 

There appears to be several different renditions.  Carrier with and w/o suspension, booms with or w/o Y guy arraignment, different superstructures, etc. 

One thing that is common though is the boom. Seems everyone more or less builds the same one.  Six studs high and three stages. 

Seems to me, by looking at blueprints of the real thing, that the boom is too small; at least if we use the carrier height as a reference.  And not by a bit.   Looking online (not the actual instructions) looks to me that the cab is 13 studs high.   Give or take a few.  If the boom is only six studs, then boom is not even half as high as the cab.  I pulled the actual plans for the crane and by my calculations, in centimeters, the boom should more like around nearly 75% the high of the cab. 

Seems to me that it easily could be increased in height to eight studs.  If this is the case, I think also it could be built with four stages, not three.  Anyone else see the same?

 

[nerdsforprez]

Also..... I am looking at the instructions for the superstructure and boom but I don't see where it shows how to set/manipulate the string.   I understand the principle on how it works, but there needs to be an outlet from where it connects with the last stage to the first stage.  Any help? 

 

 

[mkbryant]

12 hours ago, nerdsforprez said:

Seems to me that it easily could be increased in height to eight studs.  If this is the case, I think also it could be built with four stages, not three.  Anyone else see the same?

I agree that the boom could be 8 studs tall, although by my calculations the cab is correct in the instructions at 10 studs tall (or 9 depending on where you start from). However, it appears that the front cab and engine bay may be 1 stud too tall, unless the boom sits on the cab at an angle instead of perfectly horizontal.

[nerdsforprez]

On 12/12/2016 at 9:10 AM, nychase said:

Attached is a diagram for routing both cables to have extend and retract.  I have used this to great success. 

I did more research and it looks like I am not the only one with questions on how to route the string.  This diagram helps.  If I understand this correctly, the attachment points for the last stage are both at the back?  (the skinniest part) Where they connect with the first stage, the thickest part, is easy enough to determine

[nerdsforprez]

19 hours ago, mkbryant said:

I agree that the boom could be 8 studs tall, although by my calculations the cab is correct in the instructions at 10 studs tall (or 9 depending on where you start from). However, it appears that the front cab and engine bay may be 1 stud too tall, unless the boom sits on the cab at an angle instead of perfectly horizontal.

Yes, this is more or less the same calculations I came up with.  In fact, if we use your image, then the ratio of cab to boom would be 11/8 (cab is 10.9).  That means the boom is nearly 75% of the cab height.  

However, as can be seen here in @Blakbird's own render, I don't even need to see the instructions to see that the cab in the Lego version is much taller than 10 studs.  Easily 12-13.  I count 13.  If that is the case then as I said previously our current version is off by quite a bit.   6 studs high whereas the cab is 13.  So not even 50% as high.  75% versus less than 50% so indeed there is room for a much taller boom.  If increased to 8 studs high...then a four stage boom is possible.  Wondering if there are any takers tot try it out.   I am in the middle of a different project but if I get some time perhaps I will.  But would have to figure out the string issue first.....

[mitx2529]

 

On 1/28/2021 at 6:43 PM, nerdsforprez said:

Yes, this is more or less the same calculations I came up with.  In fact, if we use your image, then the ratio of cab to boom would be 11/8 (cab is 10.9).  That means the boom is nearly 75% of the cab height.  

However, as can be seen here in @Blakbird's own render, I don't even need to see the instructions to see that the cab in the Lego version is much taller than 10 studs.  Easily 12-13.  I count 13.  If that is the case then as I said previously our current version is off by quite a bit.   6 studs high whereas the cab is 13.  So not even 50% as high.  75% versus less than 50% so indeed there is room for a much taller boom.  If increased to 8 studs high...then a four stage boom is possible.  Wondering if there are any takers tot try it out.   I am in the middle of a different project but if I get some time perhaps I will.  But would have to figure out the string issue first.....

I had the same idea, so I built my crane in 2019

base on Grove 5250L

the boom I use  3->5->7 

and I was happy with the result

Edited February 1, 2021 by mitx2529

[nerdsforprez]

1 hour ago, mitx2529 said:

had the same idea, so I built my crane in 2019

base on Grove 5250L

the boom I use  3->5->7 

and I was happy with the result

Oh this is beautiful.  Great job.  I also see you made quite a few changes to the bodywork.  Wonderful job....

[mitx2529]

3 hours ago, nerdsforprez said:

Oh this is beautiful.  Great job.  I also see you made quite a few changes to the bodywork.  Wonderful job....

Thanks, crane is my favorite technic series

The moc test and fail over ten times  

It's very challenging and fun

[sbonas]

Please  post an idea as to how you made the Lego actuator

[nerdsforprez]

On 2/1/2021 at 6:27 AM, mitx2529 said:

Thanks, crane is my favorite technic series

The moc test and fail over ten times  

It's very challenging and fun

I was looking at your boom again...wondering where the extending/lowering mechanism is. Is it built in the boom? Not sure how that would be possible....

[mitx2529]

16 hours ago, nerdsforprez said:

I was looking at your boom again...wondering where the extending/lowering mechanism is. Is it built in the boom? Not sure how that would be possible....

there are four motor in the superstructure, both side had a M motor and a L motor

the actuator and the boom both are powered by L motors (use a lot gears to increase torgue)

there is no gear in the boom so that it could reach the max length around 150~155 CM as possible.

unfortunately the crane was KIA by my little 3 yrs Godzilla.

I have to repair and rebuild the moc. maybe I will share some pictures when it done.

[nerdsforprez]

Oh No!  Sorry to hear it was KIA . Impressed that you are going to try and rebuild.  Not sure I would have that type of stamina.  

I mean how did you raise the boom... not in terms of power but mechanics.  Most versions of the Grove, or even 42009 for that matter have long axles running the length of the dorsal part of the boom turning worm gears that activate the second stage of the boom.  I don't see it in yours, so I was just wondering how it raises and lowers.....

[mitx2529]

45 minutes ago, nerdsforprez said:

Oh No!  Sorry to hear it was KIA . Impressed that you are going to try and rebuild.  Not sure I would have that type of stamina.  

I mean how did you raise the boom... not in terms of power but mechanics.  Most versions of the Grove, or even 42009 for that matter have long axles running the length of the dorsal part of the boom turning worm gears that activate the second stage of the boom.  I don't see it in yours, so I was just wondering how it raises and lowers.....

 

On 2/8/2021 at 6:32 AM, sbonas said:

Please  post an idea as to how you made the Lego actuator

I used nylon line (ex: fish line, a normal 0.5mm fish line can against 15kg weight), and it raises and lowers by gravity

You can see the inside mechanics picture from brichshelf if you're interested

 

 

 

Edited March 2, 2021 by mitx2529

[nerdsforprez]

That is fairly brilliant.  I am not sure I have seen the actuator and boom controlled by string yet.  At least not the second stage.  The third stage yes, which mimicked the 42009 boom function. But not the second stage.  

 

GL with the rebuild.  Once finished... you really should make a video and share with all.  I think your way of controlling boom and actuator are unique. At least for the boom, it hides the ugly axle running along the dorsal part of the boom.