42215 Mods Improvements Alternative builds And Attachments

[Auroralampinen]

Well, tommorrow is august first. And release date for the most hated august set;). 

In this topic you can share all fixes, mods, improvements, alternative builds. And attachments wich are compatible for the 42215 boom bucket lock mechanisms.

So have fun time. And share you amazing mods, attachments and alternative builds for the 42215 in this topic:). 

[Bartybum]

Can't wait for this to become a thread filled with mod suggestions because nobody actually bought this set 

I'll start off!

1. Two L motors + independently driven tracks and motorized slewing, plus a distribution gearbox that allows multiple boom functions at once (or at least add more levers to the selector shaft)

2. Alternatively, replacement of the LAs with a pneumatic system (I assume the travel isn't high enough on the long cylinders, so perhaps you'd connect a long and short cylinder in tandem/series?)

Edited August 1 by Bartybum

[msk6003]

Remove motorise coupler and route that power to attachment PTO for jackhammer or something else

Edited August 1 by msk6003

[Paul B Technic]

The motorised coupler is an interesting idea, but I feel rerouting it makes more sense.

[jorgeopesi]

Not buying it.

[SNIPE]

So, I did a mod + some tiny tweaks, the main is using reinforced CV joints instead of UV joints inside of the boom, I think if we move the axle for the 2nd stage linear actuator to where the lime pin is then run this thru the gearbox, we can use the existing axle line for the motorized hammer drill.

Another option would be to just put a small motor in the gap shown in the first image then have extension cables going thru the rest of the boom and model to the battery box. But I want a turntable too, so I will be adding 2 more gearbox clutch rings, the functions will be:

• Turntable
• Boom stage 1
• Boom stage 2
• Bucket tiling
• PTO (used for hammer drill, and third party attachments, unused for bucket)
• Attachment unlatching

There is also a space to add a clutch ring in the middle of the gearbox.

Drive / skid steering would have their own motors and BUWUZZ in the substructure, so these dont need the superstructures motor/battery box.

This is for my semi RC mod, the other version will have no gearbox and be all motors,

Both versions will have LEDS

Edited August 1 by SNIPE

[Zerobricks]

Quickly looking at the instructions, it shuld be possible to center the battery box and add another motor. This would allow faster gearing ratio and perhaps ability to control 2 functions at once.

[SNIPE]

I have finished the model besides the bodywork and I have decided that the hammer drill will have a knob gear that mates with another knob gear at 90 degrees  which is on the latching thingy, this means we can still remove the attachment but it can still be driven without having to align teeth, say on normal gears. The knob wheels obviously make the drill spin and hammer. Not sure if its possible to make those 2 functions independent.

I will make it so that the knob wheel doesn't prevent the bucket from being attached. Hopefully third party attachments will use my system too :D

Edited August 1 by SNIPE

[schraubedrin]

On 8/1/2025 at 12:00 PM, Paul B Technic said:

The motorised coupler is an interesting idea, but I feel rerouting it makes more sense.

I feel like the motorised coupler would be awesome on a rc model.
Imagine trying to attach the shovel remotely, changing between them, ... 

[SNIPE]

mock up of the new hammer-drill attachment:

Now both functions are independant, the drill spinning can also be done manually.

I just need to modifiy the end of the excavator's boom so that the claws pivot in the opposite directions

which should give space for 2 black knob wheels that mesh with the yellow knob wheels. 

The internal pair of knob wheels are used for the hammering, one of said knob wheels is acting as a cam, and theres a small pulley wheel acting as the follower, theres also a spring placed over the drills axle, so that the cam returns back to the pulley wheel.

for now the 12 tooth knob gears are not connected to anything because I need to figure out how to fit the gears in.

There also will be a CV joint that is connected to the end of the drills axle, since the CV joint has a frictionless axle hole and the axle needs to slide in and out.

[Zerobricks]

You can use a frictionless 8 tooth gear to spin and move axle at once. 

[SNIPE]

6 hours ago, Zerobricks said:

You can use a frictionless 8 tooth gear to spin and move axle at once. 

I tried it but it was taking up too much space, or the teeth were getting caught on stuff

remember, there's 2 independently spinning axles, right next to each other.

I got it working anyway, just trying different pieces as the follower to get the best "snap" when it rides against the knob wheel, I also can't have slack in the axle when it slides, the spring must always be under tension or at its normal state because if the axle is facing down, gravity will make it unable to get pulled up for the hammer mechanism. So im trying half bushes, whole bushes and minifig utensil rings to get it right.

I think a better idea would be to use connecting rods somehow to move the axle in and out, so that its more reliable, the current design, as I said , does not always slide the axle.

Also the knob wheels are a bit messy, there's 0.5L of axles sticking out etc.

Edited August 5 by SNIPE

[Ngoc Nguyen]

On 8/2/2025 at 3:03 AM, Zerobricks said:

Quickly looking at the instructions, it shuld be possible to center the battery box and add another motor.

It might be possible, but it's not gonna be a quick fix.

The space between two frame is 15 studs. Battery box is 9 stud wide,  and one motor is 3 stud wide, which adds up to only 12. But if you put the battery box in the center, there will be no way to reach it to turn it on. So it's better to put both motors on the right side.

 

On 8/2/2025 at 3:03 AM, Zerobricks said:

This would allow faster gearing ratio

As discussed in the main thread, the main cause to the slow speed is this portion. The transmission from the output to the row of 16z clutch gears goes to three instances of gearing down: 16/20*12/24*12/16. This setup causes a x0.3 reduction in speed.

 

I just came up with a quick fix: changing the first pair of gear (16-20) into 20-16, and the second pair (12-24) into 16-20. The new ratio would be 20/16 * 16/20 * 12/16, which effectively cancels the first two pairs and only reduces the speed by x0.75. Those changes already take into account the surrounding structures.

 

I have my copy of the set but I'm unlikely to build it any time soon, so maybe someone else with the set can test this out. Maybe @kbalage can do a video about how to fix the speed problem.

Edited August 6 by Ngoc Nguyen

[msk6003]

1 hour ago, Ngoc Nguyen said:

I just came up with a quick fix: changing the first pair of gear (16-20) into 20-16, and the second pair (12-24) into 16-20. The new ratio would be 20/16 * 16/20 * 12/16, which effectively cancels the first two pairs and only reduces the speed by x0.75. Those changes already take into account the surrounding structures.

Second pair's 16t will touch 20t under.

[Ngoc Nguyen]

8 minutes ago, msk6003 said:

Second pair's 16t will touch 20t under.

It wont

  

18 minutes ago, Lim CL said:

I not sure will works or not. 

Step 133 change 24 tooth to 20 tooth gear.
Step 169 Change 12 tooth to 16 tooth gear
Step 171change 20 tooth to 16 tooth gear. 

Step 169 and 171 are for the direction switch between the two rows of 16z clutch gear so they dont affect anything.

Your suggestion for step 133 matches what I suggested above.

[Ngoc Nguyen]

1 hour ago, Ngoc Nguyen said:

I just came up with a quick fix

It sounds quick but it's only quick on Studio. In the real model, if the model is already built, a lot will have to be disassembled because of all the reinforcement and axle blocks.

[SNIPE]

Ok. I fixed the problem by not having a train wheel linkage after all to slide the drill bit in and out but rather, I tied the other end of the axle joiner to the follower, so that the follower could not slide independently on the axle. The axle can still spin however too.

I still need to tidy up the ugly knob wheels on the back somehow, maybe some help with that would be good, here is the digital model

 

Edited August 6 by SNIPE

[allanp]

Well we've had 8043, 42100 and now this. Between them we've had gearbox, no gear box, single motor, 4 motors, 7 motors, RC, no RC, physical remote, phone app dependency, no remote at all and a range of prices and piece counts ranging from not that high for a flag ship to highest part count ever for a Technic set. They have tried different ways and mods and the performance has ALWAYS been too slow and/or too weak and they have not been mechanically authentic. For me there's only one mod to make:

1) Ditch linear actuators. I didn't mind variety but after so many times I honestly never want to see them in a flagship again.

2) Use a buggy motor to drive a monster compressor made of multiple motor pumps, make it good enough to fill one air tank to a good working pressure as fast as possible (otherwise, don't use an air tank as it will make it sluggish).

3) Buy something like these: https://uk.rs-online.com/web/p/pneumatic-piston-rod-cylinders/2737685?gb=s and paint them to look a bit like Lego!

4) Stuff that lot onto the bare bones that's left of 42215 after removing the gearbox and LAs.

5) Marvel at the realistic scale speed, the power to dig and level of control you never thought possible!

6) Add motorisation to tracks/slewing functions and RC capability to taste.

 

Edited August 6 by allanp

[pleegwat]

Accurate control? On pneumatics?

[allanp]

22 minutes ago, pleegwat said:

Accurate control? On pneumatics?

Sure, why not? You don't need sub millimeter precision. We're not trying to replicate a CNC machine. Pneumatics are plenty precise enough for play. I mean, if a child can take a couple of nice big scoops and dump them exactly where he wants in the time it takes for 42215 to make a single movement.....

 

[Oh_Hi_Mao]

2 hours ago, allanp said:

 For me there's only one mod to make:

Why don't you make it by yourself? It should be easy and fun, yes? 

[SNIPE]

starting my gearbox mod:

functions are:

1.PTO1 (e.g. drill rotation)

2.PTO2 (e.g. drill hammering)

3.attachment latch/unlatch

4.LA3

5.LA2

6.LA1

7.Turntable

As ZBLJ suggested, there is space for a secondary motor by shifting the battery box accross (i'm using a buwizz 3.0 anyhow), the 2 motors are hard coupled together for more torque, since the gearbox has a lot of gears.

My gearbox has 7 levers (one per clutch ring)

The drive and steering is powered by 2 motors and a dedicated Bwi 3.0 , they are all in the lower section.

The full RC version will be the same except no gearbox and 7 motors on the top, 2 in the bottom

Edited August 7 by SNIPE

[Bartybum]

6 hours ago, allanp said:

the performance has ALWAYS been too slow and/or too weak and they have not been mechanically authentic.

42100 had a pretty decent mix of speed and power though, even if not mechanically authentic

[allanp]

11 hours ago, Oh_Hi_Mao said:

Why don't you make it by yourself? It should be easy and fun, yes? 

I want to. I should get (force) some time to play in the coming months.

[allanp]

8 hours ago, Bartybum said:

42100 had a pretty decent mix of speed and power though, even if not mechanically authentic

Power is torque (in this case digging force) x rpm (speed). Out of the 3 flagship excavators, 42100 definitely has the most torque but it's noticeably too slow for scale speed.

The thing is, many gears on axles that don't have bearings and the screw drives of the linear actuators create a bunch of friction. This friction increases dramatically when it meets resistance when trying to do any kind of work which is where the majority of the motors power is being wasted. Most of the motors output power isn't making it to the bucket.......(deleted long winded post about how pneumatics are far more efficient at getting the motors power to where it's needed when doing actual work)

You know what, I really just need to shut up and build something. I just don't have much Lego time right now.