How many pieces are in the 4.5V Supplementary Set?

4.5V Supplementary Set contains 22 pieces.

When was the 4.5V Supplementary Set released?

4.5V Supplementary Set was released in 1977.

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No. 870

Expert Builder

4.5V Supplementary Set

The 4.

Time on the shelf Retired

Released Jan 1977

View on eBay

Before you buy

Who it's for: Beginner build Vintage LEGO collectors and retro technology enthusiasts
Build: 22 pieces · about 0.2 hours Build time is an estimate.
Cost: Budget Next to other LEGO sets. Check the store for today's price.
Availability: Likely retired

★★★☆☆ 3.9 community rating

Vintage enthusiasts treasure this set for its nostalgic electrical components and early Technic elements, though casual fans may find the high secondary market price hard to justify for just 22 pieces.

📝 Our Take

The 4.5V Supplementary Set (870-1) is an absolute vintage masterpiece for hardcore LEGO historians. Released in 1977, this compact 22-piece box was designed to expand the early motorized railway and Technic systems of the era, introducing foundational mechanical components.

This set is perfect for vintage LEGO collectors and fans of retro engineering. While it only contains 22 pieces, it serves as a fascinating time capsule of how LEGO approached early motorization and power functions before modern Power Functions or Powered Up.

Skip this if you are looking for a modern building experience or a complex display piece. With just 22 elements centered around early electrical components, modern builders will find it very basic and strictly of historical interest.

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Hi! I'm BlockTalk, your LEGO expert. Ask me anything about the 4.5V Supplementary Set - building tips, investment potential, comparisons, or anything else!

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Does the vintage 4.5V motor still work after all these years? How does this 1977 supplementary set integrate with classic LEGO trains? What makes these early Technic gears different from modern gear elements? Is this set better kept sealed as a collectible or opened for vintage displays?

🧱 Building Experience

🧩

Pieces

⏱

0.2h

Estimated Build Time

📊

Beginner

Difficulty

Build Highlights:

Features classic 4.5V motor and battery box components
Includes vintage Technic gears and axles from the 1970s
Offers a nostalgic glimpse into early LEGO mechanical integration
Extremely straightforward assembly centered on wiring and gear connections

📈 Investment Analysis

↑ Trending up since release

B+

Investment Grade

Retired

As a vintage 1970s set with specialized electrical components, the 4.5V Supplementary Set occupies a unique niche in the secondary market. However, investing in vintage electronics and old plastic carries inherent risks, particularly regarding the functional condition of the motor, battery box, and rubber components. Buyers and investors must verify the working status of electrical parts, as degradation over decades can significantly impact secondary market value.

Not Financial Advice: Content is for educational purposes only. Past performance doesn't guarantee future results. Full disclaimer

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Compared to modern power function packs or Powered Up hubs, the 870-1 Supplementary Set is vastly simpler and operates on a completely different technological era of LEGO history. While modern sets offer Bluetooth connectivity and high-torque motors, collectors seek out sets like the 870-1 specifically for their authentic 1970s charm and mechanical simplicity, making it comparable to early 12V and 4.5V train accessories of the same decade.

📦 Parts Inventory

Official piece count: 22
Parts cataloged in this inventory: 14 unique parts, 22 pieces

Missing a piece? Check this set piece by piece, with look-alike colors flagged and element IDs for replacements.

A goldmine of vintage 1970s Technic elements and classic 4.5V electrical components, featuring rare grey gears, early motor assemblies, and classic yellow beams with pin holes.

🛒 Where to Buy

eBay

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💎 Notable Parts

Light Gray Motor, 4.5V Type 1 for 2-Prong Connectors without Middle Pin (1x)

Light Gray Battery Box, 4.5V 6 x 11 x 3 1/3 Type 3 [Complete Assembly] (1x)

Light Gray Technic Gear 24 Tooth Crown with Flat Teeth (1x)

Light Gray Technic Steering Pulley Large (1x)

💡 MOC Potential

🚗 Motorized vintage LEGO vehicles utilizing the classic 4.5V motor and pulley system

🏙 Retro-style automated factory machinery or conveyor belt MOCs

🏛 Working kinetic sculptures built in the classic late 1970s Expert Builder aesthetic

📰 Expert Builder News

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Inventory Statistics

Inventory version 1

14 Unique Parts

22 Official Piece Count

22 Cataloged Inventory Pieces

0 Minifigures

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4.5V Supplementary Set