LEGO Compatibility: Mega Bloks, Friends & Mould King Trains

# LEGO Compatibility Guide: Mega Bloks, Friends & Mould King Trains **TL;DR:** Mega Bloks connect to LEGO at the stud level with looser clutch, LEGO Friends is fully compatible with normal LEGO, and Mould King trains run on standard LEGO track (37.5 mm gauge, R40 curves) although their motors are proprietary Bluetooth. Browse curated Mould King and compatible sets in the Morebybourn catalog. ## What Is LEGO Compatibility and Why It Matters LEGO stud diameter is 4.8 mm with ±0.01 mm tolerance. Any brick matching this connects with comparable clutch. Wall height, anti-stud geometry, and ABS grade also matter. Reputable brands meet EN71 (EU) / ASTM F963 (US). ## Lego Mega Bloks Compatible Partially compatible — stud ~4.9–5.0 mm vs LEGO 4.8 mm. Works for decorative/large-brick use; avoid Technic pins, minifigures, and specialty parts. ## Is LEGO Friends Compatible with Normal LEGO? Yes, completely — identical stud geometry and ABS. Only difference: mini-doll figures (~41 mm) vs standard minifigures (~38 mm). ## Are Mould King Trains Compatible with LEGO? Track geometry: fully compatible (37.5 mm gauge, R40 curves). Power systems: proprietary Bluetooth, not LEGO Powered Up. ## How to Mix Bricks Without Ruining Your Build Map structural vs decorative zones, sample-test connections, use 2×4 transition plates, match color batches from one brand, and check specialty parts individually. ## How Morebybourn Fits In Morebybourn curates Mould King and other verified LEGO-compatible sets, shipped from a US warehouse with English instructions and EN71/ASTM F963 certification. ## Ready to Build with LEGO-Compatible Bricks? We offer a curated selection of LEGO alternative building sets — precision-matched to official LEGO tolerances. Contact our customer service team to place your order today.