LEGO Technic 8421 Mobile Crane

LEGO Technic set 8421, “Mobile Crane”, depicts a mobile crane within the Technic theme.

Set 8421 belongs to the Technic theme and represents a mobile crane, a construction vehicle built around a carrier chassis and a lifting structure. Its place in the theme is defined by visible engineering rather than character based storytelling, making the machine itself the focus of the model.

Construction is centered on the vehicle body, crane base and boom, using the kind of beams, axles, connectors and gear based assemblies associated with Technic models. The set relies on structure and mechanical layout to communicate the subject.

It is suited to builders who want a Technic construction vehicle for display, hands on handling or collection alongside other machinery from the theme. With no external licence indicated, it stands as a generic Technic crane, useful for comparing how the theme approaches working vehicle subjects and mechanical presentation.

Inventory of set 8421

The inventory of set 8421 lists 1,885 pieces, spare parts excluded: 201 different lots (one shape in one color) for 141 part shapes. The box also contains 22 spare parts, for small elements that are easy to lose.

Colors of set 8421

Main color: black, making up 35% of the parts, followed by light bluish gray (30%) and yellow (17%).

Part types

Most common parts in set 8421

129 of the 141 part shapes in this set have their own page on Setopedia, with their colors, element numbers and the other sets that use them. See all LEGO parts

Exclusive parts in set 8421

2 part shapes in set 8421 appear in no other set in the catalog, most often printed elements, stickers or molds specific to the model. If one gets lost, you will need to look for it individually, for example on BrickLink, rather than in another set. Counting colors, 3 lots in the set are not found in any other set.

Rebuilding set 8421 from another set

Share of the parts of set 8421 found in each of these similarly sized sets, counting shape, colour and quantity:

No similarly sized set goes above 51%: the model relies on a little-shared assortment, most of which has to be gathered piece by piece.

Size of set 8421 within its line

With 1,885 pieces, set 8421 ranks #29 out of 443 Technic sets in our database, which have an average of 658 parts. Among the 208 sets released in 2005, it ranks #4. That is 2.9 times the average Technic set size.