Automated Burnishing Machine

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Team Name M-RAD
Faculty Advisers
Client Point of Contact
Duration Fall 2016 - Spring 2017
Team Members
  • Selso Gallegos
  • Blake Warner
  • Kyle Flack
  • Fawaz Alharbi

Design, fabricate, and test automated method to burnish lead screw threads. This device should be able to burnish lead screw threads automatically with minimal user input and be able to achieve repeatability in thread backlash and torque to a finite amount.

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Lead screws are used to operate the windage and elevation adjustments on riflescopes they are manually burnished to achieve minimal backlash. This fitment is a critical part of the riflescope's performance. This is a time consuming process involves manually running the lead screw in and out of the mating part until proper fitment is achieved. This has to be done for each mated set of parts. Being able to substantially reduce burnishing time would leave machine shop resources available for other projects on the Nightforce manufacturing floor.

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Project Description


Nightforce optics prides themselves on their precision, reliability and feel of their rifle scopes. All of which rely on lead screws for precision adjustments. The elevation and windage adjustments are done by turning the dials on the top and sides of the scope. The dials contain a lead screw screw and bucket assembly to make the adjustments. Currently a manufacturing process of the lead screws is done manually. A hand finished Nightforce turret is well known for the its feel and accuracy. Team M-Rad's goal from the University of Idaho is to design and build a machine that will replicate the manual process that produces a quintessential Nightforce lead screw. The device will need to be user friendly, and possess the ability to measure torque and linear backlash of the final product. The end result will allow one manufacturer to simultaneously work on multiple lead screws at once while maintaining Nightforce precision and reliability.

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Project Goal

To design and prototype automated burnishing device which is simple to operate, adjustable to different turret models and capable of burnishing to a specified torque and backlash.

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The expected result is a proof of concept machine capable of successfully burnishing in a variety of lead screws to the agreed upon spec. The design should show a repeatable result and be able to output data regarding the burnishing operation.

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Initial prototype

Base Assembly
  • This assembly sows a prototype of the design. The Torque sensor and Linear solenoid are attached at bottom of the Base. The clamping blocks and the air piston were attached at the top of the Base. In addition, displacement sensor is attached to the solenoid and the stepper motor is attached to the end of the Arbor. The whole assembly is mounted on the plat form

Air Piston

  • The air piston pushes the clamping Blocks together to position the turrets and keep them in place during the burnishing process.

Torque sensor

  • This is a custom built torque sensor designed by team M_RAD and built in the University of Idaho machine shop to simultaneously measure the torque in the lead screws during the burnishing process.

Compact Linear Solenoid

  • It is meant to press up against the lead screw at a specified time with a specified force to measure the backlash in a turret.

Displacement sensor

  • The displacement sensor is a high resolution linear potentiometer which to measures backlash when a force is applied to the lead screw with the solenoid.

Stepper Motor

  • Drives the leads screws to specified location in the turret.

Machined Platform

  • Heavy low center of gravity platform keeps the machine stable and houses the controls of the system.

Final prototype

Final prototype.PNG

Clamp: Actuates Short Stroke Air Piston to clamp turret into the correct position for the burnishing process to begin

# of Revolutions: Set the number of revolutions for the stepper motor to drive the full length of the turret *Note: Turret Specific

L and R Start Direction: Specify which direction the stepper motor starts, based off of left vs right start on threads and location of lead screw in turret

On/Off: Turn the stepper motor on and off for spindle adjustment or in case of an emergency

Start: Initiate the automated burnishing process

Other Components

Spindle Handle: Allows for manual spindle adjustment

Ring Magnet: Suspends spindle and handle in the upper position when the machine is not being operated

Stepper Motor: Implemented larger stepper motor, 1.89 Nm to meet all torque demands

Motor Driver: Used higher quality CNC motor driver to avoid damage to the electronic system

Power Supply: Utilized a 24 volt adjustable power supply to meet the voltage need on the stepper motor

Component Photo Overview Component Photo Overview
Air Cylinder.JPG
Short Stroke Air Piston
Torque Sensor.JPG
Torque Sensor
Compact Liner Solenoid
Clamping Block
Bass Assembly.JPG
Base Assembly
Position for air.JPG
Air Position
Keyed Shaft
Stepper motor

Torque Sensor

Torque Sensor Calibration.jpg
Torque Sensor Calibration

Linear Calibration Performed on torque sensor

Final, Initail Torque Data.jpg
Torque Sensor Burnishing Data

Torque Sensor readings measured during burnishing process

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Team Members

Selso Gallegos:

Major: BS in Mechanical Engineering
Hometown: Parma, Idaho
Graduation Date: May 2017
Hobbies: Playing Guitar & Sports
Responsibilities: Meeting Organizer
Plan After Graduation: Work at Intel as a Supply Chain Engineer

Blake Warner:

Major: BS in Mechanical Engineering
Hometown: Kendrick, Idaho
Graduation Date: May 2017
Hobbies: Hunting, Fishing, Archery, Rock Climbing, Riding Motorcycles
Responsibilities: drafter / machinist
Plan After Graduation: Workforce

IMG 9943.PNG
Kyle Flack:

Major: BS in Mechanical Engineering
Hometown: Moscow, Idaho
Graduation Date: May 2017
Hobbies: Hunting, Mountain Biking, Dirtbiking
Responsibilities: Budget
Plan After Graduation: Military

Fawaz Alharbi:

Major: BS in Mechanical Engineering
Hometown: Ryiadh, Saudi Arabia
Graduation Date: December 2017
Hobbies:Playing Sports, Camping, & Hunting
Responsibilities: Wiki Page
Plan After Graduation: Workforce

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Document Archive

  • Meeting Minutes

Fall 16

Spring 16

  • Presentations

Design Review 1

Design Review 2

  • Other Project Docs

Expo Poster

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