mesmi27
Screwdriver
The screwdriver project was the final step of MECH 200, while still a major step in the entirety of my career as a Mechanical Engineer, integrating the use of a lathe, a grinder, and heat treating.
Advice
Even though this project didn’t seem like it was a lot of work due to the short amount of time to finish it and the short amount of steps compared to the clock, taking your time and making sure that every step is thoroughly practiced before actually doing it is absolutely CRUCIAL. Double, even triple checking with either a peer or a TA will help you succeed the most with the screwdriver.
Making sure that both sides of the knurls are touching the handle of the screwdriver is the best way to ensure you don’t get points taken off from messed up knurls. Having a mistake in the knurls will also make it so the handle looks like it’s concave in a way, which can mess up the way you hold on to the screwdriver.
Definitely have peers near you when you’re heat treating the shank of the screwdriver as well, since as it’s the final step before polishing, it can be very easy to mess up the temperature in which you’re stopping at, resulting in your screwdriver heat treating turning out wrong, and in most cases having to redo it with a high chance that it won’t heat treat correctly again.
Cost
Estimate
Raw Materials:
Aluminum Handle:
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1 ¼” X 5” T351 Cold Drawn Aluminum = $27.74
Steel Rod:
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1/8" X 1.5’ 316/316L Stainless Round Rod = $1.58
Total Cost of Raw Material: $29.32
Labor:
Aluminum Handle:
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CNC Lathe: 0.25 Hours
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Facing: 0.5 Hours
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Knurling: 1.5 Hours
Steel Rod:
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Drop Forging: 0.5 Hours
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Grinding: 4.5 Hours
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Heat Treating: 1 Hour
Total Time in Production: 8.25 Hours
Total Labor Cost: 8.25 X $26.23 = $216.40
Total Raw Material Cost = $29.32
Total Final Cost of Screwdriver: $245.72
Mass Production Estimate
Total Raw Material Cost (for one screwdriver): $29.32
Total Raw Material Cost (for 10,000 screwdrivers): $293,200
Total Time of Production: ~7,500 Hours/ 0.86 Years
While not taking as long as the Clock Project, the total time to create 10,000 screwdrivers would still be just as painful. It would take a total of 82,500 hours in the EMEC to manufacture all of those screwdrivers, resulting in around 9.4 years of work. Creating these many screwdrivers in the EMEC would accumulate to 2.5 million dollars!
Improving Production Efficiency
The major part in production that can become more efficient is to use a CNC Lathe to not only face the part, but also include the knurls onto the aluminum handle. Another aspect that can be included is possibly a specific holder that can hold the shank a specific way so that it not only can help the manufacturer not go above or below tolerance when grinding the shank.