ASSEMBLING AND INSTALLING A FINGERTECH 3LB BEATER BAR
BEETLEWEIGHT ASSEMBLY TIPS.
Preparation
TOOLS NEEDED
- Allen wrench (included in kit)
- Two open-end wrenches (for shaft nut)
3lb Beater
1lb Beater
TIP: SIZE YOUR BEATER BAR
Assembly Steps – Check your parts:
- Get the two kits that comprise the weapon system, the beater bar assembly kit and the beater bar electronics kit.
- Verify that both kits have the parts as shown.
3lb Beater Bar Assembly Kit
Fingertech Beetleweight 3lb beater bar Electronics kit
Includes 4 screws for engine clamp
Assembly Steps – Assemble weapon motor:
- Carefully insert the setscrew into the 15T pulley. Using the allen wrench, back the setscrew up slightly (counterclockwise) until you feel it engage the threads to avoid cross-threading.
- Slip the pulley onto the S2838 brushless inrunner 2970KV motor shaft.
- Ensure that the setscrew faces the flat side of the motor shaft. Tighten the setscrew.
- Install the motor in the 28mm motor clamp by placing the two clamp halves together and installing the two top screws to hold the clamp together. Use the two long screws. Make the clamp tight enough to hold the motor, but loose enough so that the motor can move forwards and backwards to ensure the pulley is aligned with the slot.
TIP: SETSCREW ADJUSTMENT
Add setscrew to pulley
Carefully add setscrew in kit to weapon motor pulley
Pulley installed on Weapon Motor
Install pulley with setscrew facing flat side of motor shaft
28mm Weapon motor in mounting
Showing motor, mounting bracket, and pulley
Fingertech 28mm motor mount CAD drawing
Long screws at top of mount, short screws at bottom
Assembly Steps – mount motor assembly to chassis:
- Screw the 28mm motor clamp to the chassis using the remaining two button head screws (shorter screws) and an allen wrench. Make sure the bracket is loose enough for the motor to move back and forth.
- Thread the pulley through the slot in the chassis. Move the motor in the bracket until the pulley belt can go on the pulley, the pulley is lined up with the slot, and the belt runs straight through the slot without binding.
- Tighten the screws on the bracket so the motor can no longer move. Depending on the room in your chassis, you may need to remove the four corner mounting screws and pull the drive motor out to be able to reach the screws on the top of the motor bracket..
Mount motor clamp to chassis
Using the two screws, mount the motor clamp to the chassis.
Thread belt through slot
Thread the toothed belt through the slot in the front plate and around the pulley on the weapon motor.
Pulley alignment diagram
Top view diagram showing how to align the motor and pulley to the slot in the chassis
Assembly Steps – Assemble the beater bar:
- Make sure both SCE55 bearings are in the pockets on either side of the bare beater bar. Sometimes they are lightly pressed in and look like part of the beater bar, sometimes they are loose and come out easily. Make sure both are in place.
- Turn the beater bar on its end. Take the 30T pulley and the delrin ring and line up the holes with the beater bar. Make sure that the countersunk holes on the delrin ring face outwards.
- Insert the two flathead screws from the beater bar kit, and screw the delrin ring, 30T pulley, and beater bar together using an allen wrench. Make sure the bearing is trapped in the pocket between the beater bar and the 30T pulley. See picture of bearing installed in the beater bar.
End view of Bare Beater Bar with Bearing installed
Note the bearing in pocket at the end of the beater bar
Beater Bar showing order of assembly
Make sure bearings are at either end of the beater bar
Pulley and Delrin ring on Beater Bar
Order: Beater Bar with bearings –> 30T pulley –> Delrin ring with countersinking facing outward to accept screws.
Tighten two screws to attach pulley to beater bar
Use allen wrench to tighten screws. Don’t overtighten and deform delrin ring.
Assembly Steps – Install Beater Bar into chassis:
- Making sure the bearing is in place on the other side of the beater bar that you just assembled and slip the beater bar in between the “ears” of the chassis, engaging the 30T pulley with the pulley belt you just threaded through the slot. Most chassis has some flex, so you may have to use a small amount of pressure to slip it in place.
- Line up the holes on the right (non-pulley) side of the beater bar and chassis.
- Insert the 3lb Beater Bar shaft through the right side of the chassis, bearing, and beater bar. Continue to insert the shaft to engage the holes in the pulley side of the beater bar. Line up the holes in the chassis and complete insertion all the way through chassis, beater bar, and chassis again.
- Install the Beater Bar shaft nylon locknut onto the threaded end of the shaft now protruding from the chassis.
- Now tighten the nut on the shaft using two wrenches, one on each side, until the nut is close to the chassis, but not touching. Be careful not to tighten the nut until the beater binds in the chassis, leave some slack to allow the beater bar to rotate.
Loop pulley belt around pulley
Bring the beater bar into the chassis at an angle to easily loop the pulley belt around the pulley.
Beater Bar Installed in chassis
Showing proper orientation of beater bar assembly in chassis
Attach nut to beater bar shaft
Finger tighten nut to beater bar shaft
Tighten Beater Bar to chassis using two wrenches
Use a wrench on each hex end of the Beater Bar shaft
Assembly Steps – add Beater Bar Teeth:
- Add a locknut to a tooth as shown. Install a tooth into the beater bar, tightening the tooth until the locknut is completely compressed and tight.
- Repeat for all eight teeth.
TIP: OPTIMIZING FOR WEIGHT
If you are having a weight problem, you can use less teeth, but make sure it is balanced on each side. If you have only two on one side, make sure you have only two on the other side. For example on side 1, you could have teeth in position 2 and 3, while side 2, you could have teeth in position 1 and 4. The important thing is that both sides have an equal number.
Beater Bar Tooth and Lockwasher
Make sure to add lock washers before screwing teeth into the Beater Bar
Install teeth on Beater Bar
Use Allen wrench (included in kit) to tighten beater bar teeth and lockwasher to beater bar and tighten significantly
Assembly Steps – Connect the ELEctronics:
- Pretty straightforward. Connect the red wire to the red power wire coming off of the battery AFTER the switch. Connect the black wire to the black wire coming off the battery.
- Connect the three bullet connectors on the ESC to the three bullet connectors on the Beater Bar motor.
- Plug the connector into the receiver on Channel 3 (most common configuration).
TIP: BEATER BAR RUNNING BACKWARDS
If your Beater Bar is running the wrong way, the fix is easy. Locate the three bullet connectors coming off of the ESC. Swap any two of those connectors and the motor will change direction. You can also reverse the motor by changing the settings on your transmitter.
SAFETY TIP: CONNECT POWER ! AFTER ! THE SWITCH
Make sure the weapon ESC’s power input (red wire) is connected AFTER the power switch. If it is connected before the switch, the switch will not disconnect power to the weapon ESC, and the weapon cannot be turned off. Click the “THIS NOT THIS” diagram for more clarity.
Wiring Diagram
Complete Wiring Diagram for combat robotics weapon system
Receiver wiring closeup
Closeup view of how ESC wires plug into receiver
Correctly wire the ESC
It’s important to wire the weapon ESC AFTER the switch so the weapon can be turned off
© 2026 ItGresa Consulting Group, Inc. d/b/a ItGresa Robotics. All original text, graphics, layout, tables, illustrations, and educational content are copyrighted. Product names, trademarks, and manufacturer technical information remain the property of their respective owners and are used for identification and educational purposes. Technical information in this guide is adapted from manufacturer documentation published by FingerTech Robotics Ltd.