T70103 Tamiya Universal Gearbox – 101:1, 269:1 & 719:1

The T70103 Tamiya Universal Gearbox is a compact, versatile motorised gearbox designed for educational construction, robotics, mechanical models, and STEM projects. Its pressed-metal frame makes it one of the smallest gearboxes in Tamiya’s Educational Construction range, while its selectable high gear ratios provide slow output speeds with increased torque for mechanisms requiring controlled movement.
The gearbox can be assembled with three different gear ratios: 101:1, 269:1 or 719:1. A worm gear enables these high reduction ratios, allowing students to investigate how gearing changes motor speed and available torque. The main output shaft can be positioned in four different directions, providing flexibility when incorporating the gearbox into student-designed mechanisms. A second smaller output shaft operates perpendicular to the main output shaft, creating additional possibilities for mechanical designs. Tamiya’s catalogue confirms the three ratios, two shafts arranged at right angles, four possible mounting positions for one shaft, a Type 130 motor, and a 3mm hex output shaft.

Key Features

• Three selectable gear ratios – 101:1, 269:1 and 719:1
• High reduction ratios for slow, controlled mechanical movement
• Compact pressed-metal gearbox frame
• Main output shaft can be positioned in four different directions
• Auxiliary output shaft operates perpendicular to the main shaft
• Final two gears are metal for a durable output stage
• Worm gear enables high gear reduction
• 3mm hex output shaft
• Type 130 motor included
• Suitable for mechanical, robotics and engineering projects

What’s Included

• Tamiya Universal Gearbox components
• Type 130 DC motor
• Gears for selectable ratios
• Pressed-metal gearbox frame
• Output shafts
• Assembly hardware

Three Gear Ratio Options

The T70103 can be assembled with one of three gear ratios:
101:1 – Higher Speed
Provides the fastest output of the three configurations. Suitable when a project requires more movement speed and less gear reduction.
269:1 – Medium
Provides a balance between output speed and torque, making it a useful general-purpose configuration for mechanical models.
719:1 – High Reduction
Provides the slowest output speed and greatest mechanical advantage of the three configurations. This is useful for projects requiring slow, controlled movement.
The selected ratio is determined during gearbox assembly. Tamiya lists these three ratios specifically for the 70103 Universal Gearbox.

Flexible Output Shaft Positions

One of the key advantages of the Universal Gearbox is its flexible output arrangement. The main shaft can be installed in four different positions, while the gearbox also provides a second shaft positioned at right angles to it.

This provides students with greater freedom when designing mechanisms because the gearbox can be adapted to suit the direction of movement required rather than designing the entire project around a fixed output position.

Understanding Gear Reduction

A gearbox reduces the high rotational speed of an electric motor to produce a slower, more useful output.
For example, a 101:1 gear ratio means the motor turns approximately 101 revolutions for one revolution of the gearbox output. At 719:1, the motor turns approximately 719 revolutions for one output revolution.
This makes the T70103 particularly useful for demonstrating the relationship between speed, torque and gear ratio.

Classroom Use / Learning Outcomes

Students can use the T70103 to:
• Understand how gearboxes operate
• Investigate gear ratios
• Compare input and output speed
• Explore the relationship between speed and torque
• Investigate worm gears and gear reduction
• Examine perpendicular power transmission
• Understand how rotational movement is transferred
• Design mechanical systems around different output directions
• Incorporate motors and gearboxes into design projects
• Test and evaluate different mechanical solutions

Project Ideas

• Robotic mechanisms
• Model vehicles
• Lifting mechanisms
• Mechanical arms
• Moving displays
• Model machinery
• Crank mechanisms
• Automated models
• Slow-moving mechanisms
• Student engineering projects

Teacher Benefits

• Three gear ratios available from one gearbox
• Excellent practical demonstration of gear reduction
• Students can see how changing gearing affects mechanical performance
• Multiple output positions provide design flexibility
• Compact construction is useful for smaller projects
• Suitable for structured experiments and open-ended design briefs
• Integrates mechanical construction with electrical and electronic control

Perfect For

• STEM projects
• Design and Technologies
• Systems Engineering
• Robotics
• Mechanical engineering activities
• Model making
• Gear ratio experiments
• Motorised projects
• Student design briefs
• Tamiya Educational Construction projects