As a young engineer at my first job with Caterpillar Engine division in Peoria, Illinois, my boss asked me to look into the cost of a part that was named “Washer”. The part was simple and is shown in Figure 1. The part had a 5 inch outer diameter, was .75 inches thick and had four half inch diameter holes one inch from the center of the part. The four holes in the middle of the part were clearance holes for bolts. the bolts went through the part and held a pulley onto the engine’s crank shaft. The part was machined from cold rolled steel and cost $13.63 In 1990. Caterpillar required 60,000 of these a year.
Figure 1. Two views of a part named “Washer”.
I called the supplier and asked how the part was made. He sent me the process plan for the part. I noticed that the holes were drilled one at a time. I wanted to pounce! I suggested that the holes all be drilled at the same time. The supplier said that he could lower the price $2 a part if he “gang” drilled the holes but we would have to move the holes a little farther apart. Wow, I thought a savings of $120,000 a year in my first month at work. I left a note for my boss and went home happy.
The next day my boss dashed my hopes. He informed me that it was too late in the design process to change the design of the crank shaft to accomadate the design change to the washer. We already had 10,000 engines in the field and spare parts in warehouses all over the world. If we had only had talked to the manufacturing engineers when we were designing the part we could have saved alot of money with a simple change. Instead we had to live with the expensive washer!