Cutting Tool Engineering
January 2012 / Volume 64 / Issue 1

Magic carpet ride

By Tom Lipton

This month’s column is a safety lesson with a happy ending that could have easily gone the other way. For the people involved, the planets aligned and everything came out alright with nobody losing their head—literally.

The shop I was working in at the time was extremely busy and on a crushing deadline to complete a large machine. I was working on a large stainless steel fabrication. To our dismay, we expected to run short of 11-gauge sheet metal on this critical part. I informed the project engineer, who then mobilized the purchasing agent. After several phone calls and some mad scrambling, they found a sheet locally that we could pick up.

Our shop helper was an older man who worked to stay busy. We cornered him well before lunch and told him we needed this sheet picked up right away.

The shop pickup truck was a smaller model equipped with an overhead lumber rack. For most material deliveries, it worked fine. However, nobody stopped to think how the helper was going to secure a 4 '×10 ' sheet and return it safely by himself. Oops!

We were working furiously for hours before somebody realized the helper had not come back. This was before cell phones were common, so we had no indication anything was wrong. More time passed before we started to really wonder what was going on.

The buyer called the metal supplier and confirmed our man had picked up the material several hours ago. Several hours!? Where the heck was he? We guessed he may have had a flat tire or possibly stopped for lunch. Everybody was pretty upset and impatient that he hadn’t returned.

Finally, in the late afternoon, he wheeled into the yard, ashen faced and wide-eyed. To his credit, he at least had the sheet. The first thing I noticed was the stainless sheet was haphazardly tied and damaged. As he told the story, we realized it could easily have been a horror show.

Because the sheet didn’t fit in the bed of the small pickup, the helper and whoever was assisting him decided to put it on the lumber rack. From a weight perspective, that was probably OK, but once you factor in the aerodynamic properties of a 1⁄8 "-thick sheet of stainless, the idea loses some appeal. Apply a liberal dose of bad judgment and junior knot making, and you have just set the stage for a spectacular event.

At the metal supplier, they removed the sheet from the skid—a critical mistake. I guess it fit on the lumber rack better without the additional complication of a wooden skid. The sheet was then lashed down to the rack with the black and orange plastic rope that everybody seems to use to tie stuff to vehicles. The rope was just passed around the edge of the sheet and down to the tie downs on the rack. Did I mention the sheet metal had a sheared edge? No padding or abrasion-resistant material was placed between the rope and sheet—a second critical mistake.

After loading the sheet and “securing” it, the helper jumped on the freeway to quickly get back to the shop—a third and final mistake.

While the truck was going 60 mph, vibration caused the flailing 200-lb. stainless para-wing strapped to the rack to saw through the plastic retaining rope and liberate itself skyward. The helper said it got real quiet when the sheet broke loose. He looked in his rearview mirror and saw cars behind him changing lanes at the same time. How nobody was killed or injured before the corrosion-resistant guillotine came to rest is a mystery. Apparently, several cars hit or ran over the sheet because the sheet had skid marks on it.

Unbelievably, the helper got help from these lucky motorists to get the sheet back on the rack. One guess what he tied it down with: yes, the same rope. The only difference was he tied the sawed ends together. The metal gods must have been smiling on him for the remainder of his adventure because he made it back to the shop without losing the sheet again.

The ironic part was we had enough material to do the original job and didn’t need the additional sheet, which remained behind the metal rack for years before I salvaged a couple usable pieces. I often think about that sheet flying through the air when I get behind a vehicle with something that’s not tied down very well. CTE

About the Author: Tom Lipton is a career metalworker who has worked at various job shops that produce parts for the consumer product development, laboratory equipment, medical services and custom machinery design industries. He has received six U.S. patents and lives in Alamo, Calif. Lipton’s column is adapted from information in his book “Metalworking Sink or Swim: Tips and Tricks for Machinists, Welders, and Fabricators,” published by Industrial Press Inc., New York. The publisher can be reached by calling (888) 528-7852 or visiting www.industrialpress.com. By indicating the code CTE-2012 when ordering, CTE readers will receive a 20 percent discount off the book’s list price of $44.95.
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