mostlytechnic

[REVIEW] 42121 Technic Heavy Duty Excavator

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38 members have voted

  1. 1. Your opinion of the set?

    • Poor
      2
    • Below Average
      1
    • Average
      8
    • Above Average
      22
    • Excellent
      5


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Technic Heavy Duty Excavator

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Thanks to Lego and EB for this review set. 

Over the years, Lego has made LOTS of excavators. Bricklink lists 25 of them. There's City excavators on trailers. There's Duplo excavators for the little kids. There's even a Lego Dimensions tiny excavator from the Lego Movie. What we care about here though are the 9 previous Technic excavators. They range from 1984's pneumatic excavator to the massive 4000 piece Bucket Wheel Excavator in 2016. The new Excavator fits into the middle of the range, and below, I'll compare it to two of the older versions. 

Name: Heavy Duty Excavator

Set Number: 42121

Pieces: 569

Price: $39.99

Minifigs: 0

Theme: Technic

 

The Box Front

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There's some decent construction graphics in the foreground and background, but what is this pose? The set photo is taken with a wide angle lens from close range, so it's MASSIVELY distorted. The bucket appears to be almost as big as the rest of the machine. 

 

The Box Back

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The functions appear to be quite standard - rotation, rolling, and control of the arm in 2 locations. Check out that B-model though! Like the Hovercraft, this set has a GREAT looking alternate build. Sure, the arm is a similar function, but the rest of the vehicle looks great and completely different. I'm looking forward to trying it out when the instructions are released. 

 

The Box Top

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Remember what I said about the distorted front image 4 seconds ago? They used the bucket for the 1:1 sample on the top of the box! That really makes it hard to judge size for anyone not familiar with Lego and Technic in particular. 

 

The Contents

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4 sets of bags, and I like that the tread links are in separate bags of their own! There's a couple extra in each, so you do still have to count (or just see what fits) but it's still nicer than having them all mixed in. 

The sticker sheet is nice and small. Also, there's not much yellow, which makes sense when you realize how much of the part volume goes into the arm and treads. 

The Build, Part 1

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In an unusual move for Lego tracked vehicles, bag 1 doesn't start with the chassis. It starts at the other end and builds the arm. That's a great way to start off with the "interesting" parts. I also REALLY liked that it reaches a nice, functional point here. You can turn the two grey axle connectors and make the the arm function. That's useful to verify that you did it all right, and it gives the builder a chance to see how things work one section at a time. 

There are two mini-LAs here to move the arm. There's also a fake hydraulic cylinder on the end of the arm. It's made from an axle and connector, so it's all in light grey. Which made me wonder... why did Lego design the mini-LAs with the colors that they did? The piston part should be light grey and the outer body should be darker. I'm sure they did it this way to match the regular LAs, which have light grey body and a metal piston, but I'd prefer the colors be reversed. 

The Build, Part 2

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Bag #2 adds the body of the excavator. Here's the bulk of the yellow parts, and it makes a decent shape. There's not a ton being hidden underneath. This is directly controlled - the knob on the back and one on the right side each drive a segment of the arm. 

 

The Build, Part 3

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That is a lot of non-color in bag 3. Since there's no motorization or connection between the tracks and the body of the excavator, these are pretty simple. 

 

The Build, part 4

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Bag 4 adds a few cosmetic parts and provides the 1x2 liiftarms and cones. I have to say, why both with the arms? They're nearly impossible to scoop up with the excavator. On the other hand, the controls on this set are easy to use and work well. It takes a reasonable amount of turns on the knobs to move the arm, and it's plenty easy for kids to use. 

 

The Driver?

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This is way smaller than minifig scale, but just look at that cabin! It is so well done. A big windscreen for visibility... a nice red seat... a couple control levers... and a decent panel. 

 

The Family

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I currently have the 42121 (2021, 569 pieces, $40), the 8294 (2008, 720 pieces, $60), and 8419 (2005, 286 pieces, $20). They all use essentially the same arm, with 2 movements (none of them have independent control of the bucket). The 42121 uses 2 knobs to directly control 2 mini-LAs. The 8294 has a single knob, run through a simple 2 position gearbox, to control two full-size LAs. 8491 uses two knobs on the rear, both driving worm gear setups, to move the arm via linkages instead of linear actuators. 

I find these a fascinating comparison. The first two are semi-close in part count, but 8294 is SO much bigger. I think that's due largely to simply using bigger pieces. It has fewer tread links, but it uses the large ones instead of the small ones. It has full-size LAs instead of mini. The liftarms making up the body and the arm are longer. 

The two yellow sets look so close in size from this angle, but are so different in part count and price. 42121 has a lot of parts used in cosmetics (the cab, a fully enclosed body, fake vents, etc). 8419 is old-school Technic. It's just an outline of the vehicle, not wasting pieces on decoration. It also used rubber tracks, saving 80+ pieces from the new version. 

 

The Reach

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From overhead, 42121 is clearly the mid-size of this group. It's also clearly a newer generation of Technic. Both the older sets are skeletal. 

 

The Ratings

Design: 8

Build Experience: 9

Features: 7

Playability: 7

Parts/Value: 8

Overall: 8

As always, my ratings are based on the size and target market for the set. This is another nice 8+ Technic set. The build was easy but both looks and works well. This is a pretty good playable set, although I actually dinged it for including the 1x2 liftarms. They just don't work to scoop up. You have to hold them in place for the bucket to get them up. For some sets, having "material" makes sense - the cement mixer and the bucket excavator are great examples there. For these smaller sets, don't waste the piece count on that. If kids want to dig in Lego, they've probably got a box full of parts to dig in that'll work much better than a few pieces included here. Also, as usual, the tracks don't move if you're pushing it on a smooth surface (table, hard floor, etc). It needs to be on carpet for the tracks to work correctly. 

Despite those minor dings, I think this is a great set for its target market. This isn't meant to compete with the $100+ sets like the motorized 8043 or massive Bucket Wheel Excavator. This is a set kids will get and love. I particularly appreciate that the instructions start with building the arm and even call out to test the functionality before moving on to bag 2. That's a great user experience right there. 

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I'm glad there's finally an affordable and good-looking excavator, definitely an "outstanding" set!

Thanks for the review!

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Im incredibly torn on this set, i have 0 interest in construction equipment usually, but for the price it just seems like a very nice little thing, and it might be quite easy to convert into a crawler crane

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2 hours ago, vectormatic said:

Im incredibly torn on this set, i have 0 interest in construction equipment usually, but for the price it just seems like a very nice little thing, and it might be quite easy to convert into a crawler crane

I think a crane mod would be pretty easy indeed. You've already got the mini-LA to adjust the boom angle, and then use the second knob to drive a spool of string. 

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I dig it. It looks good for what it is, the design is neat with little holes in the main body and the B model looks good also.

However, thinking that this would primarily be aimed at the younger demographic I think it would have been better for them (and not only) to make it minifig scale since it's already close to it.

In any case I'll probably get it, build it once, maybe also try the B model but then break it down for parts.

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I liked it when I first saw it, but now I'm not so sure. Looks kind of flat. Which has inspired my next MOC, the Pancake-Vator! (Just kidding.)

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Thanks again for this great review and the nice pictures!

I like this set, it seems, there's also a great B-model.

I never thought about that, but your question about the colour of the mini-LA is interesting!

Something is weird with those tread links though, it doesn't seem to fit with the rest of the body.

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On 2/16/2021 at 2:41 PM, caiman0637 said:

I liked it when I first saw it, but now I'm not so sure. Looks kind of flat. Which has inspired my next MOC, the Pancake-Vator! (Just kidding.)

Yes but it's still the most accurate one out of all of them!

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The functions work too slowly.

The rear knob should be on the left side of the body frame.

So i voted for below average. The set is neither good enough as a toy for children, nor good enough for adults.

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10 hours ago, Parazels said:

The functions work too slowly.

The rear knob should be on the left side of the body frame.

I didn't feel like it was slow, compared to Technic sets I've built over the last 20 years. It felt pretty typical to me. 

And I agree, the rear knob being on the left would be easier to operate and more ergonomic, but I bet they didn't want to mess with the cosmetics on the left (vents, cabin, etc)

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18 hours ago, mostlytechnic said:

I didn't feel like it was slow, compared to Technic sets I've built over the last 20 years. It felt pretty typical to me. 

This is a set for kids, who normally are very impatient. So the slow control scheme is not right for the target audience of the set.

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Thank you for this great review. The photos are outstanding (sorry Jim)!

For me it’s a really good looking set. First I wasn’t very interested in this it, but after seeing your comparisons I want to have this selection on my shelf!

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Does anybody else also thinks that this will be difficult (not-so-easy?) to take apart without (non-Lego) tools:

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?

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1 hour ago, anyUser said:

Does anybody else also thinks that this will be difficult (not-so-easy?) to take apart without (non-Lego) tools:

 

?

I can quickly think at least two ways to take this apart with only other Lego pieces. You can put a liftarm on the pin, then insert a bar into the axle-pin and pull it out with the liftarm as the bar prevents pin from coming out of the liftarm. Another, probably even easier, method is to put an axle-pin into the end of a liftarm and use it to push the 3L axle-pins out of their places.

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I can see how a second copy of this set could be converted easily into a Pipe Layer, similar to the Volvo one.

I like it and just waiting for the normal 3rd off on Amazon to pick up a couple of copies.

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17 hours ago, howitzer said:

I can quickly think at least two ways to take this apart with only other Lego pieces. You can put a liftarm on the pin, then insert a bar into the axle-pin and pull it out with the liftarm as the bar prevents pin from coming out of the liftarm. Another, probably even easier, method is to put an axle-pin into the end of a liftarm and use it to push the 3L axle-pins out of their places. 

 

16 hours ago, Void_S said:

Thanks for your suggestions. I didn't think about assembling a tool = using more than one part for deconstruction.

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1 hour ago, anyUser said:

 

Thanks for your suggestions. I didn't think about assembling a tool = using more than one part for deconstruction.

In the 90's there used to be tips for disassembly tools in instruction booklets of every larger set. For some reasons that's not the case anymore.

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5 minutes ago, howitzer said:

In the 90's there used to be tips for disassembly tools in instruction booklets of every larger set. For some reasons that's not the case anymore.

Given that a good deal of current sets aren't designed to be taken apart, they'd be superfluous anyhow.

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9 hours ago, howitzer said:

In the 90's there used to be tips for disassembly tools in instruction booklets of every larger set. For some reasons that's not the case anymore.

Off topic but I'd love to know more. Any links to old scanned images?

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9 hours ago, ukbajadave said:

Off topic but I'd love to know more. Any links to old scanned images?

Here's one from 1989: 

Spoiler

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Thank you for the great photos.

I was looking for that trans-clear panel 24116, I find it a shame it's frosted instead of clear.

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