The screwdriver was a fantastic project that included a few more advanced steps in its manufacturing process. It consists of a steel drill rod that was drop forged, tempered, and hardened into a flat head screwdriver. The handle is made of turned aluminum, complete with high-quality knurling for grip.
Advice
This project has some parts where you will be using dangerous tools. When the professor and/or GTAs give you a tool demo, take good notes! This helps keep you safe and knowledgeable when you work with the machinery to produce your screwdriver.
Take care when grinding the tip down as well, sparks will fly onto you and your clothing, so wear more safety gear than you think you need. I chose to wear a welder's jacket and a faces shield which kept the sparks from burning holes in my clothing.
Take measurements frequently during the grinding process so you don't take off too much! I ground the diamond shape down a bit too much, and although it looks okay, I lost a couple of points.
Cost
Handmade Screwdriver
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Screwdriver Raw Stock: $5 drill rod, $10 molded aluminum, $15 total
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Manual Labor: $300, 15 hours at $20 per hour
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12 hours to face, turn, ​knurl, forge, and heat treat
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3 hours to grind and finish with sanding and polishing
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The total cost of one handmade screwdriver would be around $315. This has to be taken down by automating the process since not many people would buy a nice screwdriver for the absurd price of $300.
Not only that, but if I was commissioned to make 10,000 of them, it would cost the buyer 3.15 million dollars. They'd have to wait 17 years for all 10,000 of them to be finished.
Cost
Auto-machined Screwdriver
Assuming similar costs to run the automated machines like described in the Clock and Trivet sections:
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It's around $3/hour to run the machines​
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It takes 2 hours to complete one screwdriver (longer than the others due to forging and heat treating processes)
One screwdriver would cost $18, which is more reasonable. If someone placed an order for 10,000 they could expect to have them all in 2.28 years if the machines ran constantly, for a price of at least $180,000.
Process of Automation
Forging and Heat Treating
The first thing to change would be this process. Instead of finishing the handle first and then the drill rod screwdriver, it would make more sense to forge and treat the drill rods before giving them their handles. A machine would forge the end of the drill rod for the tip of the screwdriver, and the opposite end with a lip to receive the handle later. (This will help the handle stick to the drill rod). The rod would be tempered and hardened and then go to receive the handle.
Molding and Turning
Once the drill rod is finished, a machine would insert it into the handle mold and hold it in place while hot aluminum is poured in.
After it has cooled, the screwdriver can be placed in a CNC lathe where the handle end will be faced and turned down to the specified measurements using a premed program.
Knurling
A knurling tool could be attached to another CNC lathe, and the lathe could be programmed to spin the handle against the tool while providing cutting oil.
After this, the screwdriver would be done. A technician can remove it from the lathe and clean off excess chip and cutting oil.