2018 Scholarship Winner

Travers Tool is very proud to announce the winner of our 2018 scholarship contest, Dave Domizi from Athens Technical College in Athens, GA. With almost 50 entries, Dave's stood apart for its technical execution and thorough presentation.

Project Overview

Project: Single Cylinder Compressed Air “Wobbler”

*I’ve included as many in-process work photos as I have for this project, as well as a short video of its basic mechanical action. I also included a few photos of another manual lathe project - a tap wrench with brass knobs of my own design, which was a great project for inner and outer threading.

Project Goals

  • Successfully assemble a project with numerous small, moving, interacting precision parts
  • Refine fit & finish skills on manual machines using various different materials
  • Perform an offset lathe cut for crankshaft with pin
  • Cut taper lock parts-Cut smooth, flowing internal and external radii using a manual cutter on the lathe
  • Cut tiny left hand threads

Tools

*This project was completed using only manual machines, including:

  • Manual metal lathes
  • Manual milling machines
  • Three and four jaw chucks for lathes-Lathe face collet
  • Manual radius cutting jig for lathe-Various cutting bits, boring bar, drill bits, reamers, etc.
  • Various calipers, micrometers, thread gauges, etc.
  • Sine bar & gauge blocks
  • Tap
  • Various abrasive polishing papers and cloths, file, etc.

Materials

  • Cold rolled steel
  • Hot rolled steel
  • Aluminum
  • Brass

Work Process

The wobbler project was really enjoyable. Successfully executing such tiny parts on the old, beat up school machines was challenging. All parts were cut from raw stock, with the exception of the small nipple fitting for connecting the compressed air line, and the spring for the cylinder connecting rod assembly.

A lathe face collet was used to hold the large hot rolled steel stock for the project base. After initial dimensioning of the stock, the lathe compound was set up using a sine bar to set the angle for cutting the Morse taper mounting hole in the center of the base. Achieving a quality finish on hot rolled steel was tricky - SLOW WORK!

Immediately after cutting the base, I dimensioned some aluminum round stock for the frame, set up the manual radius cutter, and cut the interior radius. After a second setup, I cut the external radius for the end/top of the frame - it was nearly perfect, requiring almost no blending with file or cloth. I then used the unchanged compound setup to cut the corresponding taper for the bottom of the main frame, which bore a strong resemblance to a bowling pin. With both parts cut using the same setup, the taper was all but guaranteed to fit properly, and it did.

The rough frame part was moved to the mill to cut the ledge and drill and ream the various holes for the air flow, nipple fitting, crankshaft bushing, and cylinder pin. Finally, it was moved back to the lathe for cutoff.

Several other small parts were made on the lathe, including the flywheel, piston, threaded connecting rod, rod sleeve, crankshaft bushing, small brass assembly nuts including a cap nut for the crankshaft with tapped left hand threads, and a small aluminum press fit jig fixture for holding the crankshaft stock to cut the offset pin.

The rough crankshaft was cut and threaded on the lathe, then pressed into the offset holder jig and moved to the mill to shape the head and remove most of the stock from around where to pin would be cut to reduce the force of cutter impact during that operation. Then, the tiny offset pin was turned on the lathe and the crankshaft pressed back out of the holder jig.

The brass cylinder body was milled and bored for the piston. Then, I used assorted polishing papers and cloths from the school, and from my own shop stock, to put a fine mirror polish surface on the brass, eventually achieving a polished part at exact spec. Everyone in the shop wanted to know how I achieved this finish.

After all of the parts were completed, I performed test fits and carefully checked the dimensions for the press fit of the brass crankshaft bushing into the main frame. The bushing was pressed into the frame, and the Wobbler was lubricated and assembled. I masked off the brass crankshaft cap nut to prevent any finish marring and then used a powered hand drill to run the Wobbler for several minutes to work the parts, breaking it in nicely. Then, compressed air was attached to run through the machine for several minutes, and it worked very smoothly. It may have been a small, rudimentary machining project, but it was very satisfying to complete, and to watch it run so well!

 

Personal Statement

My name is Dave Domizi. In January 2016, I began working toward a degree in the Machine Tool Technology program at Athens Technical College in Athens, GA, and it has been an incredibly interesting and rewarding experience. The program is excellent, and I’m excited for the day when I will graduate and move forward into my new career. I currently hold a 4.0 GPA and am learning and mastering new skills every week. This past summer, I completed the first level online course at Mastercam University with excellent marks, and I plan to take the Mastercam professional certification as soon as possible. During the Fall 2019 semester, I worked on a group student project building a small Stirling Engine, which gave me significant additional experience setting up, running and programming for CNC machines. I completed all of the CAD drawings for the team in Mastercam, then worked on the tool-pathing for my parts, and the group is now cutting the roughly forty parts on Haas CNC lathes and mills, hopefully finishing the engine this semester. If everything continues as planned, I’ll be graduating sometime next year with an Associate Degree in Machine Tool Technology, including a CNC Specialist Certificate. Every bit of help that keeps me on track is life-changing, and the Travers Tool Scholarship would be a huge help to me during the coming years.

I find metal work and machine work fascinating. It’s a new but natural extension of the work that I’ve been doing for many years. Since 2002, I have run a guitar and stringed instrument repair shop in Athens, GA, working in a variety of disciplines including metal, wood, electronics, finishing, structural repairs, modifications, etc. I use a wide range of tools for this work - mostly smaller hand tools, routers, etc, but working with larger CNC equipment to do precision machining of metal and wood has been a desire of mine for a long time. After sixteen years repairing and building stringed instruments, I feel that I have the experience to move into designing and manufacturing guitars and guitar related hardware. Having the skills to program and run CNC equipment for part prototyping and fabrication will be crucial to my business, both financially and for production capacity, and it will give me the edge that I’ll need to succeed.

I’ve always wished that I had earned a college degree, and it is now important business for me. My income has leveled off at a very modest amount, and despite my wife’s job our family of four lives relatively month-to-month. It bothers me that, if my wife’s employment fell apart for any reason, I would not be able to fully carry the family on my own. As an older student, it has been challenging to balance school, two jobs, and family life with two young children, but it will bring a huge sense of security to my life, having an in-demand job skill that allows me to work as a machinist, programmer, etc, and make a great living for my family. The Travers Tool Co. scholarship would make it possible for me to begin acquiring the new tools that I’ll need in the machine trade – something that is very difficult, given our family’s budget. Please consider me for the Travers Tool scholarship. It would be a tremendous aid to my career and life. Thank you very much for your consideration!