Impact Testing Device - Nightforce Optics

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Nightforce scope
Sponsor: Nightforce Optics
Duration: Fall 2015 - Spring 2016
Team Name Team Consistent Hit
Faculty Advisor: Michael Maughan
Mentor: Dillon Savage
Team Members:
  • Kylie Touchstone
  • Jason Borth
  • Jay Anderson
  • Dillon Glover
  • Currently Nightforce Optics manual impacts each scope that goes through the line, our mission was to make this process automatic. We developed an automatic pendulum to consistent hit the scope. Which can apply different forces depending on the operator's needs. It improved safety and decreases human error.

    Problem Definition[edit]


    Each and every Nightforce riflescope is impact tested as it goes through the production line. This is currently accomplished by impacting the scope by hand against a padded steel pedestal in multiple orientations. After impact the riflescopes are inspected for damage and functionality. When the production line workers manually impact the riflescopes there are inconsistencies with the impacts throughout the day and amongst the workers.

    Design Goal[edit]

    Nightforce Optics is seeking a prototype/proof of concept of an impact device that will consistently deliver a cyclic impact of set value between 200-2000 g’s. The prototype needs to allow the user to quickly remove the scope from the device, hit all sides of the scope, and fit an area smaller than 2’x2’x3’. In addition, the prototype cannot cosmetically damage the scope and needs to operate safely.

    Design Specifications[edit]

    Specification Threshold Objective
    Impact Mode Single impact Single and cyclic (3 repetitions)
    Impact Region All four sides and forward impact 360° capability
    Calibration Can be calibrated to a specific g force NA
    Scope removal while testing Removed and collimated after each side impact and forward impact NA
    Size of machine 2'x2'x3' 1'x1'x2'
    Data collection Output to laptop/flash drive, record time and g force Real time output to external screen
    Scope sizes Attachment method for 30mm and 34mm diameter tubes universal, adjustable attachment method
    Machine use Research and development / proof of concept Production floor ready
    Operator Anyone should be able to operate NA
    Time to operate As long as needed ≤45s
    Safety Can not automatically or unintentionally go off Additional safety guard to protect operator's limbs or fingers
    Surface conditions Can not damage the surface or bend the trim ring NA

    Project Learning[edit]

    Underlying equations[edit]

    The Work-Energy Principle states that the change in the kinetic energy of an object is equal to the net work done on the object. since the impacting device will come to a complete stop, the change in its kinetic energy is equal to the initial Kinetic energy.(Average impact force) x (distance traveled) = (change in kinetic energy)for a linear system F*d=1/2 m*v^2 and for a rotational system F*d=1/2 I*ω^2. from these equations we can then estimate the impact force and acceleration felt by the scope

    Design matrix for power input[edit]

    Variable weight Linear actuator Electric motor Mechanical Spring Pneumatic
    Price 3 4 (12) 3 (9) 5 (15) 3 (9)
    Speed 5 2 (10) 4 (20) 4 (20) 4 (20)
    Size 3 3 (9) 5 (15) 5 (15) 5 (15)
    Durability 4 3 (12) 2 (8) 3 (12) 4 (16)
    Availability 2 5 (10) 5 (10) 3 (6) 5 (10)
    Ease 2 3 (6) 4 (8) 2 (4) 3 (6)
    Calibration 5 4 (20) 5 (25) 2 (10) 4 (20)
    Weighted totals 79 95 82 96


    Initial design ideas / Brainstorming[edit]

    design 1
    design 2
    design 3
    design 4

    Testing and Project Learning[edit]

    Simulation of Pendulum
    First prototype pendulum
    Accelerometer data output
    A Solidworks based simulation of a pendulum for validating mathematical model and compare theoretical and experimental results. A rough prototype pendulum used to help understand the efficiency of momentum transfer between a mass and the scope Data output from accelerometer of a scope being impacted by the pendulum. Notice the high level of noise, this is something we will have to figure out in order to obtain better data.

    Final/Detailed Design[edit]

    Solidworks frame model
    Adjustable pendulum arm
    Modified scope rail for clearance and attaching.
    Solidworks model of final design excluding the pneumatic hoses, regulator and actuator. Variable length pendulum arm with replaceable tread on heads. Part is made with a solid shaft machined to slide inside an outer pipe. Picture depicts a CATIA finite element analysis that was performed on the part. Modified scope rail to allow for scope turret clearance and holes with counter-bores for attaching the rail onto the T-slot Aluminium rails.

    Finished Product[edit]

    Front view of impact testing device
    Top view of impact testing device
    Side view of impact testing device and laser engraving.
    The final, manufactured riflescope scope impact testing device. Top view showing the scope mounting system. Side view showing the protective Plexiglas shielding and custom laser engraving.

    Team Information[edit]

    Picture Info Bio
    2015 ImpactTestingDevice Kylie.jpg Kylie Touchstone:
    • major: Mechanical Engineering
    • email:
    • home town: Boise, ID
    I am a senior mechanical engineer at the University of Idaho, graduating spring of 2016. Classes that I have enjoyed include: Mechanics of Material, Fatigue and Fracture and both my CAD classes working with SolidWorks and CATIA. I interned with HP in Vancouver, WA this summer on the writing systems team and had a blast with it. Some of my hobbies included snowboarding, hunting, camping, reading and gaming. Some of my favorite games are Bioshock, Portal, Skyrim, Dragon Age Inquisition, and League of Legends. Favorite Authors are Brandon Sanderson and Christopher Pike.
    2015 ImpactTestingDevice jason.jpg Jason Borth:
    • major: Mechanical Engineering
    • email:
    • home town: Genesee ID
    I began school at the University of Idaho in the fall of 2012 and am now a senior in mechanical engineering. My favorite part about mechanical engineering is that you are not limited to a specific area of study. One day you are learning about non symmetric bending of beams and the next day, rocket science. As lifelong Idaho resident, I enjoy doing all the outdoor Idaho things shooting, hiking, etc. My favorite YouTube channels include but are not limited to, Veritasium, SmarterEveryDay, DemolitonRanch, ColinFurze, jimmydiresta, Numberfile, and Ed Bassmaster.
    2015 ImpactTestingDevice jay.jpg Jay Anderson:
    • major: Mechanical Engineering
    • email:
    • home town: Cheney, WA
    I am from Cheney WA and began school at the University of Idaho in the fall of 2012, I am a senior in mechanical engineering, and work for the US Army Corps. of Engineers as a Hydropower Engineer. I choose mechanical engineering because I have loved airplanes all of my life and want to design either aircraft or rocket engines. I was born and raised a vandal and really love Moscow. I like to go hiking, shooting trap and skeet, swing dancing, and photography. My favorite Youtube Channels are SmarterEveryDay, Vsause, C.G.P. Grey, Numberfile, Minutephysics, and CrashCourse. I also enjoy listening to podcast such as Hello Internet, Cortex, and The Orbital Mechanics.
    2015 ImpactTestingDevice dillon.jpg Dillon Glover:
    • major: Mechanical Engineering
    • email:
    • home town: Asotin WA
    I am from Asotin WA but have mostly lived in Idaho throughout my life. I began my engineering education at the University of Idaho in 2012 where I am a senior now. I am a current engineering intern at CCI/Speer where I work in manufacturing. I chose to be an engineer because of my interest in mechanical systems and how they work. Other than work and going to school, you will find me in the mountains bugling at elk or fishing a mountain lake. If I am not hunting or fishing I am usually riding dirtbikes with my wife or hitting the snowy hills on my snowmobile.

    Document Archive[edit]

    Meeting Minutes[edit]


    Project Schedule


    First Snapshot Poster

    Design Review Power Point

    Detailed Design Review Power Point

    DFMEA (Design Failure Mode and Effect Analysis)

    Engineering Expo Poster


    Wiring Diagram