REV FIRST Global User manual

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA
fg
FIRST Global Building Guide

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA
TABLE OF CONTENTS
1INTRODUCTION ...................................................................................................................................................................... 1
1.1 HOW TO USE THIS GUIDE ............................................................................................................................................. 1
1.2 REQUIRED TOOLS .......................................................................................................................................................... 1
2ELECTRICAL COMPONENTS.................................................................................................................................................. 2
2.1 ELECTRONICS................................................................................................................................................................ 2
2.2 SYSTEM WIRING DIAGRAM .......................................................................................................................................... 4
2.3 DC MOTORS ................................................................................................................................................................... 5
2.4 SERVO MOTORS ............................................................................................................................................................ 6
2.5 SENSORS........................................................................................................................................................................ 7
2.6 BATTERY ........................................................................................................................................................................ 8
3MECHANICAL COMPONENTS ............................................................................................................................................... 9
3.1 EXTRUSION .................................................................................................................................................................... 9
3.2 BRACKETS...................................................................................................................................................................... 9
3.3 JOINTS ......................................................................................................................................................................... 12
3.4 BRACKET ASSEMBLY TECHNIQUES .......................................................................................................................... 14
3.5 BEARINGS .................................................................................................................................................................... 16
3.6 LINEAR MOTION V2..................................................................................................................................................... 19
3.7 HINGES......................................................................................................................................................................... 23
3.8 HARDWARE.................................................................................................................................................................. 23
3.9 ADAPTERS ................................................................................................................................................................... 27
3.10 MOTION COMPONENTS ............................................................................................................................................. 28
3.11 WHEELS........................................................................................................................................................................ 29
3.12 SPROCKETS AND CHAIN ............................................................................................................................................ 31
3.13 GEARS .......................................................................................................................................................................... 34
3.14 PULLEYS AND ROUND BELT....................................................................................................................................... 37
4BASIC BUILDING GUIDE ....................................................................................................................................................... 38
4.1 DRIVE TRAIN GUIDE .................................................................................................................................................... 38
4.2 ARM GUIDE .................................................................................................................................................................. 41
4.3 MINI ROBOT EXAMPLE ............................................................................................................................................... 41
ALL COMPONENTS (1:1 Scale) ................................................................................................................................................... 42

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 1
1INTRODUCTION
1.1 HOW TO USE THIS GUIDE
This guide is intended to be an introduction to the REV Robotics Building System that is being used in FIRST Global. The
goal of this document is to give an overview of the parts included in the system and some example building techniques
which will make building your robot easier. The system itself was designed with flexibility in mind, where every bracket
and part can be mounted in infinite locations along the REV Rails, making it easier to tune your design and speed up
iterations.
There are already lots of examples in this document, but we’re committed to continuing to add content to keep making it
more accessible for people to build with REV.
Feel free to pick out specific sections of interest and read those, there is no need to consume this document in any
sequential method.
1.2 REQUIRED TOOLS
The REV Robotics 15mm Building System for FIRST Global only requires a few basic tools. Please see Table 1 for
recommendations.
Table 1: Recommended Tool List
Tool
Required
Use
5.5mm Nut Drive
Yes (Included)
M3 Hardware
5.5mm Combination Wrench
Yes (Included)
M3 Hardware
1.5mm Allen Wrench
Yes (Included)
M3 Shaft Collars
2mm Allen Wrench
Yes
Linear Motion Kit
Small Pliers
Optional
Working with Chain
Chain Breaker
Optional
Working with Chain
Hack Saw
Yes
Cutting Extrusion
Chop Saw
Optional
Cutting Extrusion
Band Saw
Optional
Cutting Extrusion
Diagonal/Flush Cutter
Optional
Trimming Brackets to Customize
File/Sandpaper
Optional
Trimming Brackets to Customize

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 2
2ELECTRICAL COMPONENTS
2.1 ELECTRONICS
2.1.1 Introduction
Robots are made up of mechanical structures and the electrical components that move and control them. Electronics is a
broad category which includes motors, sensors, and programmable controllers or hubs. The REV Robotics Building
System has two kinds of Hubs: Control Hub and the Expansion Hub (Figure 1). The Control Hub has an integrated
computer module running Android and is where the robot code runs, while the Expansion Hub only provides a break out of
additional ports. Please note that every robot must have one Control Hub, but adding an Expansion Hub is optional.
Figure 1: Control Hub and Expansion Hub
2.1.2 Hub Ports
Figure 2: Control Hub and Expansion Hub Rear Ports
Mini USB
This connector is used for firmware updates
USB 1 and 2
Are used for connecting peripheral devices such as a keyboard and mouse. (Control
Hub Only)
Micro USB
Used to download robot code from a computer. (Control Hub Only)
HDMI
Connect an external monitor. (Control Hub Only)
Micro SD
Accepts a standard MicroSD memory storage card which can be used for data
logging. (Control Hub Only)

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 3
Battery
The battery connectors are a pair of male and female XT30 Connectors. Connect the REV
Robotics 12V Slim Battery (REV-31-1302) to either connector. If your robot has both a
Control Hub and an Expansion Hub you can use a battery extension cable to connect power
between the two.
DC Motor Power
Connect motors to the hub’s four built in speed controllers using these ports. The connector
is a 2-pin JST VH connector.
DC Motor Encoder
Each motor has an encoder built-in. Connect the encoder cable to the same port that the
motor is powered from. The connector is a 4-pin JST PH connector.
Servo Motor
Connect up to six Servo motors. The connector is a standard 0.1” Pitch male header. This
connector is not keyed, so be sure to connect it in the correct orientation.
+5V Power
Auxiliary 5V power for robot accessories. The connector is a standard 0.1” Pitch male
header. This connector is not keyed, so be sure to connect it in the correct orientation.
Analog
Analog input for 0-3.3V sensors. The connector is a 4-pin JST PH connector.
Digital
Digital input or output for 3.3V digital devices. The connector is a 4-pin JST PH connector.
I2C
There are four 3.3V compatible I2C buses. Multiple I2C devices can be connected to the
same port, as long as they each have a different address. See the I2C sensor section for
more details. The connector is a 4-pin JST PH connector.
RS485
This port is used to communicate between the Controller Hub and an Expansion Hub. The
connector is a 3-pin JST PH connector.
UART
This port is output only and used for debugging. The connector is a 3-pin JST PH connector.
Status Indicator
LED indicator for robot mode and for debugging
Button
This button is used to pair the Controller Hub with the Robot Driver Station and can also be
programed to have additional functions.

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 4
Most of the connectors on the Control Hub and Expansion Hub are keyed, meaning that the connector is shaped so that it
is not possible to plug the cable in backwards. The Servo Motor ports and the 5V Power ports are not keyed and the pin
out is shown in Figure 3Figure 3
Figure 3: Servo and 5V Power Port Pinouts
2.2 SYSTEM WIRING DIAGRAM
Figure 4: System Wiring Diagram

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 5
2.3 DC MOTORS
DC motors are used to power wheels and control moving robot parts, like arms. The Core Hex DC Motor (Figure 5)
included in the FIRST Global Kit has a 5mm hex socket drive shaft surrounded by six m3 mounting holes on both sides
called the Motion Interface Pattern. The back of the motor has a 2-pin connector for power and a 4-pin connector for an
encoder cable. The normal rotation, the direction of spin when the motor is going “forward,” is marked with an arrow on
the front of the motor.
Figure 5: Core Hex DC Motor
Both sides of the Core Hex motor have a Motion Interface Pattern for bolting to any of our motion brackets (see Table 2).
The Motion Interface Pattern consists of six evenly spaced bolt holes. The bolt hole pattern on both sides of the motor
allow it to be mounted in multiple orientations (Figure 6).
Figure 6: Core Hex Motor Front and Back Mounting Plates
The offset between the front and back mounting plates shown in Figure 6 enables the motor to be mounted at 12 different
motor orientations, including vertical and horizontal when both sides of the motor are used. Figure 7 below shows a
horizontally mounted motor which is flipped from the vertical motor with the front facing out. Note that when the motor is
flipped, the direction that the shaft spins is also flipped.
Figure 7: Core Hex Motor Mounting Options

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 6
The female hex shaft of the Core Hex Motor allows for any length 5mm hex shaft to be inserted through the body of the
motor (Figure 8). The motor can drive wheels or gears on either side of the shaft, or a single shaft can be put through
multiple motors to increase the power. If multiple motors are used on a single shaft, be sure that they are being controlled
in the same direction to prevent damage.
Figure 8: Hex Core Motor Mounted with 5mm Shaft Inserted
2.4 SERVO MOTORS
Servo motors are a specialized kind of motor which can be controlled to move to a specific angle instead of continuously
rotating like a DC motor. Instead of a hex output shaft like the DC motor, servos have an output spline (Figure 9). A spline
is a specific groove pattern cut into the shaft which allows the rotation of the servo motor to be transmitted to the
attached Aluminum Servo Horn or Servo Adapter (see Table 6). Splines are like keys, so only matched types will fit
together. The REV Robotics Servos all use a 25T spline pattern. If the gears or spline of the REV Robotics Smart Robot
Servo become damaged, they are replaceable using a Replacement Gear Set. See the Replacement Gear Guide for
instructions.
Figure 9: Servo Motor
Common servo motors take a programmed input signal range and map that to an angular range. For example, for a servo
with a 180° range, if the input range was from 0 to 1 then a signal input of 0 would cause the servo to turn to point -90°.
For a signal input of 1, the servo would turn to +90° (Figure 10). Inputs between the minimum and maximum have
corresponding angles evenly distributed between the minimum and maximum servo angle.
Figure 10: Servo Motor Angular Mode Output

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 7
The REV Robotics Smart Robot Servo is a programmable servo that can switch between standard servo mode, continuous
rotation, and custom angular modes. To unlock these modes, use the SRS Programmer to configure and test the Smart
Robot Servo. See the SRS Programmer User’s Manual for specific information on how to configure the Smart Robot Servo.
2.5 SENSORS
2.5.1 Analog Sensors
Analog sensors provide measurement data within a continuous range by measuring the voltage output of a sensor.
Analog sensors are good for measuring things like angle of rotation, brightness, and distance because the data they
provide spans a continuous range which would correspond to angle, intensity, and range, respectively.
Sensor
Description
Potentiometer
Potentiometers have a limited measurement range of 0° to 180° and will be damaged if they
are forced to rotate farther. The potentiometer has a 5mm hex socket and a Motion Interface
Pattern. Connect this sensor to a shaft to measure the angle of rotation of the shaft. A typical
example is using a potentiometer to measure the angle of a robot arm.
2.5.2 Digital Sensors
Digital sensors are very simple to use because they only provide one single piece of data, which is either a 0 or 1. A good
example of a digital sensor is a limit switch. The switch is either pressed (1), or not pressed (0).
2.5.3 I2C Sensors
I2C is a common electronic communication standard that allows a master device, the Hubs, to communicate with
multiple devices, slaves, attached to the same port. Each connector on a Hub is a separate I2C bus and many different
sensors can be connected to each of the four I2C busses available on both the Control Hub and Expansion Hub. Every I2C
slave device has an address, a number, which is normally fixed by the manufacturer. All of the devices on an individual I2C
bus must have a unique address so that the master can communicate with one sensor at a time. If two devices have the
same address, such as when using two of the same kind of sensor, they must be used on different I2C busses.
Sensor
Address
Description
9-Axis IMU
0x28
Each Control Hub and Expansion Hub has an 9-axis IMU (inertial measurement unit)
built-in connected to I2C Port 0. An IMU uses built in accelerometers, gyros, and
magnetometer to collect data about how it is being moved around and then
combines all of those measurements to provide more accurate data about the
speed, rotation and heading of the robot.
Color/Distance
0x39
This sensor can be used to detect specific primary colors or measure the distance
to an object that is within 10cm.
2.5.4 Encoders
Encoders convert information about the rotation of the motor shaft into electrical signals that can be read by the Control
Hub. Inside the Control Hub these electrical signals can be used to provide real world data to make better programming
decisions. For example, a programmer can use this information to calculate how far the robot has gone or how fast a
wheel is spinning. Every DC motor from REV Robotics comes with a quadrature encoder already installed. The encoder
cable should be plugged into the same port from which the motor is powered.
The encoder is a relative encoder, which is also referred to as incremental encoder. It provides information about the
motion of the shaft (e.g. forward at 5 RPM) and only provides data while the shaft is rotating. Stated another way, relative
encoders return information on the incremental change of the motor output shaft. and only provide pulses as the motor
turns; interpreting these pulses into useful information must be done externally in the Control or Expansion Hub. A

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 8
relative encoder does not know what position it is in when it is turned on, but it is possible to create a calibration program
that can be run at every start-up to obtain a reference point from which to calculate an angle.
The encoder uses four wires, 3.3V Power, Ground, Channel A and Channel B to communicate data back to the Hub (Figure
11). When the motor is rotating, the Hub can calculate the direction and speed of the motor.
Figure 11: Encoder Connector Pinout
2.6 BATTERY
The Slim Robot Battery for FIRST Global is a 12V 3000mAh NimH battery with inline 20A mini ATX fuse for protection
(Figure 12). The battery has a female XT30 Connector. This connector is polarized so that the battery cannot be plugged
in incorrectly.
Figure 12: Slim Robot Battery
2.6.1 Battery Safety
Batteries store tremendous energy in a small size and it is important to take care of your batteries to keep them in good
working order and to prevent dangerous conditions.
-Batteries should only be charged with approved chargers
-Never leave a charging battery unattended
-Do not leave a battery plugged into a robot when it is not in use and avoid other cases where a battery will be
accidentally over discharged
-Batteries should be fully charged before they are put in storage for extended periods
-Properly dispose of any battery which has been damaged or which shows any signs of excessive heat or melting

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 9
3MECHANICAL COMPONENTS
3.1 EXTRUSION
REV Rail Extrusion is 15mm x 15mm square profile clear anodized Aluminum. Slots accept standard M3 hex-head bolts
or nuts, rather than expensive t-nuts. The five-hole pattern on the end of the extrusion can be M3 tapped (Figure 13). The
slots in the extrusion allow attached brackets to be slid and retightened to an infinite number of locations. This makes
things like mating gears and tensioning chain easy. Fine system adjustments can occur at any point in the system
development which helps foster an iterative design process.
Figure 13: Extrusion and Cross-Section Details
3.2 BRACKETS
3.2.1 Bracket Features
Plastic brackets are nominally 3mm thick and made from molded nylon (PA66). Figure 14 lists key features of the Plastic
Brackets for the REV Robotics Building System. Check individual product CAD models for exact dimensions for each
bracket.
Figure 14: Motion Bracket Feature Details
Alignment Ribs: Protrusions on one side of the bracket seat into the extrusion channel and help align the bracket
to the extrusion and add strength and rigidity to joints.
Extrusion Mounting Holes: M3 Mounting holes are on an 8mm pitch.
Bearing Seat: Brackets with a 9mm hole can be used to mate with any of the plastic bearings to support a shaft.
Motion Interface Mounting Pattern: Circular M3 hole pattern on a 16mm diameter is used to mount to REV
Robotics shaft accessories such as motors and potentiometers.

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 10
3.2.2 All Bracket Types
Table 2 and Table 3 show all of the motion and construction brackets in the REV Robotics 15mm Plastic Building System.
Table 2: Motion Brackets
Motion Bracket
REV-41-1303
Rod End Motion Bracket
REV-41-1304
Gearbox Motion Bracket
REV-41-1315
Indexable Motion Bracket
REV-41-1313
Bearing Pillow Block
REV-41-1317
Table 3: Construction Brackets
30° Bracket
REV-41-1308
45° Bracket
REV-41-1307
60° Bracket
REV-41-1306
90° Bracket
REV-41-1305
120° Bracket
REV-41-1311
135° Bracket
REV-41-1310
150° Bracket
REV-41-1312
Variable
REV-41-1318
Servo Bracket
REV-41-1319
Inside Corner Bracket
REV-41-1320
Lap Joint Bracket
REV-41-1321
Hex Pillow Block
REV-41-1317

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 11
3.2.3 Pillow Blocks
The REV Robotics building system uses plastic nylon (PA66) molded pillow blocks (Figure 15). The bearing pillow block
can be used with the long through-bore or end cap bearings to provide a low friction shaft support. The hex pillow block
directly interfaces with a 5mm shaft which can be used to drive a light duty arm or as a dead (non-spinning) axle support.
Figure 15: Pillow Blocks
3.2.4 Variable Angle Bracket
The variable angle bracket is a special kind of construction bracket which allows 2 pieces of extrusion to be mounted
together at any angle from 0-180° (Figure 16). For additional strength, after the ideal angle has been set, miter the end of
the extrusion which will be connected using the arced slot and drill a hole along the alignment mark arc so that it lines up
with the extrusion channel and add another bolt to stop the angle from changing.
Figure 16: Adjustable Angle Bracket Example
3.2.5 Indexable Motion Bracket
The Indexable Motion Bracket is a specialized version of the Motion Bracket. This bracket is made up of two pieces: the
smaller piece has alignment ribs and fits onto the extrusion, while the larger piece has a motion interface pattern and a
bearing seat (Figure 17). On the inside face, where these brackets meet is a fine sawtooth pattern which mesh when they
are bolted together to hold the shaft offset. To adjust the offset, loosen the bolts and adjust as needed, retighten with the
teeth fully engaged to secure (Figure 18).
Figure 17: Indexable Motion Bracket

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 12
Figure 18: Shaft Offset Using an Indexable Bracket
3.3 JOINTS
3.3.1 Constructing Joints
In most cases joints should have at least two sides joined with brackets for strength and stability. Commonly this involves
taking two of the same kind of bracket and sandwiching the pieces of extrusion (Figure 19), but this can also be two
different kinds of brackets such as a 90 Degree Bracket and an Inside Corner Bracket installed on the same corner.
Figure 19: Install Brackets on Both Sides of the Joint
When using brackets to connect extrusion, the joint will be much stronger if the end of the extrusion is beveled (cut at an
angle) so that the end will sit flush with the face of the adjoining extrusion (Figure 20).
Figure 20: Extrusion with Beveled Joint

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 13
Different bracket angles can be combine to make structures (Figure 21). The joints in this example are all beveled to sit
flush against the adjoining extrusion.
Figure 21: Combine Angled Brackets to Create Structures
3.3.2 Corner Bracket Joint Examples
There are three main ways to create extrusion joints that are at 90 degrees (Figure 22). The most common is the 90°
bracket which mates to pieces of extrusion at 90° in the same plane. The second is an inside corner bracket is
functionally equivalent to the 90° bracket. The third type is called a lap joint bracket which allowed to pieces of extrusion
to “overlap.”
90° Bracket
Inside Corner Bracket
Lap Corner Bracket
Figure 22: Corner Bracket Examples
3.3.3 Three-Way Joint Examples
For space efficient 90 degree joints and making 3-way intersection joints a Corner Cube is the most common solution.
Mounting a corner cube to 15mm Extrusion requires the ends of the extrusion to be tapped, see 3.4.5 End-Tapped
Extrusion Method for details.
Compact 90 Degree
Three-Way Joint
Figure 23: Corner Cube Examples

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 14
3.4 BRACKET ASSEMBLY TECHNIQUES
There are several different ways to assemble brackets and extrusion; these are explained in detail in this section. There is
no right or wrong way, but different techniques may be needed if the end of the extrusion has become blocked during the
assembly process.
3.4.1 Bracket Assembly Method
Using pre-assembled brackets is the simplest way to install a bracket on extrusion. Brackets are preassembled with nuts
and bolts before being slid into the extrusion slot and tightened (Figure 24).
1. Insert bolts into the desired bracket holes.
2. Put nuts onto the inserted bolts. Do not fully tighten these nuts, just a few turns will be enough. If
using locknuts, finger tight is appropriate. There should be enough exposed thread on the bolt so that
the bolt head can slide into the channel in the extrusion.
3. Slide the bolt heads into the extrusion slot. Note that the bolt heads will only fit if they are turned with
flat sides parallel to the extrusion slot. Using a gentle shaking motion on the bracket while aligned
with the slot can help align the bolt heads.
4. Slide the bracket to the desired location and tighten the nuts.
Figure 24: Preassembled Bracket Installation Method
3.4.2 Bolt-First Method
The bolt-first method may be necessary when certain constraints prevent the bracket from sliding into its final position.
Bolts are slid into the extrusion slot and then aligned with the bracket and nuts (Figure 25).
1. Slide the required bolts into the extrusion channel.
2. Slide the bolts so that they are approximately spaced to fit into the bracket.
3. Place the bracket on the the protruding bolts.
4. Add nuts to the exposed bolts, slide the bracket into position and tighten.
Figure 25: Bolt-first Assembly Method

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 15
3.4.3 Access-Hole Method
The access-hole method is necessary when the ends of the extrusion profile are blocked preventing bolts from entering
the slots. Drill a 6.5mm (1/4”) hole centered on the slot in a convenient location away from the final bracket position
(Figure 26).
1. Drill a 6.5mm (5/16”) hole centered on the extrusion slot away from the final bracket location. Drop
the bolt heads into the hole and then slide them into the slot one by one.
2. Align the bolts so their spacing approximately matches with the bracket hole spacing.
3. Place the bracket on to the protruding bolts.
4. Start the nuts on all of the protruding bolts. Slide the bracket to the desired final location and tighten
the nuts.
Figure 26: Access-hole Assembly Method
3.4.4 Drop-In Bolt Method
Drop-in bolts are specialty bolts with a modified head profile which allows them to be inserted into the extrusion channel
without needing to drill an access hole (Figure 27).
1. Place drop in bolts in the extrusion slot.
2. Align the bolts so their spacing approximately matches with the bracket hole spacing.
3. Place the bracket on to the protruding bolts.
4. Start the nuts on all of the protruding bolts. Slide the bracket to the desired final location and tighten
the nuts.
Figure 27: Drop-in Bolt Assembly Method

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 16
3.4.5 End-Tapped Extrusion Method
The end-tapped extrusion assembly method is good for quick simple structures to verify spacing of a design. This is not a
primary building method and once the correct spacing has been established, a bracket should be added to reinforce the
joint.
1. Thread the M3 bolt into the center hole on the end of the extrusion. Using a standard driver, the bolt should
self-tap into the end of the extrusion. An actual M3 tapping tool can also be used if desired.
2. Tighten the bolt until it feels securely threaded into the hole. Leave enough thread exposed that the head can
be slid into the channel of another piece of extrusion.
3. Slide the extrusion with the bolt in it to the desired location and then turn the extrusion to tighten the bolt.
4. This joint is sufficient for quick, light duty testing, but brackets should be added when the design is finalized.
Figure 28: Extrusion to Extrusion Quick Joint
3.5 BEARINGS
3.5.1 Molded Plastic Bearings
The REV Robotics Building System uses plastic acetal (Delrin/POM) molded bearings. These bearings have a maximum
9mm outer diameter (OD) which fit inside the 9mm inner diameter (ID) hole in the all the motion brackets (Figure 29).
Figure 29: Plastic Bearing in a Motion Bracket

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 17
These Delrin bearings provide stable, low friction axle support in our nylon brackets. The two materials were carefully
chosen because they have a very low coefficient of friction and are also incompatible materials, meaning that they will not
stick together under extreme heat. REV Robotics Plastic Bearings come in three varieties (Table 4).
Table 4: Bearings
End Cap Bearing
REV-41-1322
Short Through-bore Bearing
REV-41-1326
Long Through-Bore Bearing
REV-41-1329
End cap bearings are closed on one end, so when these bearings are placed on both ends of a shaft and fit into
motion brackets the shaft is free to rotate but is fully constrained laterally (sideways).
Short Through-bore Bearings are low profile pass through bearings intended to seat directly into any of the
motion brackets. These low profile bearings have a 3mm contact surface which makes them flush with one side
of the motion plate. Shaft collars are recommended to laterally constrain the shaft.
Long Through-bore Bearings are full depth bearings which can be used with any of the motion brackets or the
bearing pillow block. Unlike the end cap bearing, because a shaft can pass though this bearing it can be used
with the bearing pillow block to have a pivot between to fixed shaft ends. Shaft collars are recommended to
laterally constrain the shaft.
There are number of different bearing, shaft collar, and motion bracket combinations that are recommended. See Figure
30 for a visual representation of some of the recommended combinations.
Figure 30: Bearing Assembly Combination Recommendations

FIRST Global Building Guide Created by REV Robotics 2019, Licensed Under CC BY-SA 18
Figure 31 - Figure 34 shows several possible combinations for bearings, motion brackets, and pillow blocks. In these
figures the brackets are all depicted as facing “up” but brackets can also point “down” just as well.
Figure 31: Motion Brackets and End Cap Bearings
Figure 32: Motion Bracket and Short Through bore Bearings
Figure 33: Pillow Blocks and End Cap Bearings
Figure 34: Pillow Blocks and Long Through bore Bearings
3.5.2 Ball Bearings
The REV Robotics Building System also uses a metal ball bearing. This bearing has a 12mm outer diameter (OD) which fit
inside the 12mm inner diameter (ID) hole of the metal ball bearing mount (REV-41-1452). For use with the 5mm Hex Shaft
place a 5mm Hex to 8mm Bearing Insert (REV-41-1528) into the ball bearing. Ball bearings provide better performance in
high load or high speed applications than the Delrin bearings.
Figure 35: Flanged Bearing Example