What is the Bore?

5 mm Hex Bore

5 mm hex, pioneered by REV Robotics, is a common bore in FIRST Tech Challenge. It is good for torque transfer in a small form factor, that doesn't require a machine key or a set screw.

AndyMark has this option in many of our compliant wheels and intake options, as well as a Nub Option.


6 mm Round Bore



6 mm D-Bore



8 mm Bore

(0.313 in. - aka 8 mm Round, 8 mm Key, CIM Bore)
An 8 mm Bore means it has been designed to be used with a motor or gearbox with CIM style mounting.

These products can be used in one of two ways. A keyway is cut into the shaft requiring the use of a 2 mm machine key to transfer torque OR they are designed to be pressed onto the shaft transferring torque via the friction of the interference fit.


Nub Bore

A Nub Bore consists of an 8 mm center pilot with 2 or 4 clearance holes for 6-32 screws on a 16 mm diameter circle.

This is our most common FIRST Tech Challenge Bore and is compatible with our line of Nubs as well as hubs from most other FTC vendors. It can be thought of as a universal FTC mounting pattern as Nubs have a variety of different bores available depending on your shaft needs.


3/8 in. Hex Bore

3/8 in. hex is the younger brother to 1/2 in. hex. This bore size is a crossover between FIRST Robotics Competition and FIRST Tech Challenge. Many of our products are available in both bores.

In FRC, 3/8 in. hex is fantastic for when you prefer 1/2 in. hex but are limited on space or weight and load is not a concern. In FTC, it is great all the way up to high loads.


10 mm DD-Bore

(aka Double D Bore, Dual D Bore)
Used for the original AndyMark Snowblower motor, if you still have one available.


0.5 in. Hex Bore

1/2 in. hex, pioneered by AndyMark, is our most popular bore size. It is the ubiquitous standard in FRC for it's ability to transmit torque without a machine key.


14 mm Hex Bore

14 mm hex is found on our 2 in. Omni wheels. This larger size accommodates inserts made to fit other popular bores. This is typically not used by itself, but in conjunction with adapters to different bore sizes.


Bearing Bore

A Bearing Bore product has 1.125 in. pockets in it, designed to accept any bearings that are 1.125 in. outside diameter.

These are typically used when the wheel is driven by some other means such as chain or belt, and a shaft is only needed to support the weight, not transmit torque.

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