Bolted joints are a staple of modern engineering and manufacturing practice.
Modern life is modern because of our mastery of materials and bolted joints.
I would be hard pressed to name a technology that does NOT depend on bolted joints in some aspect of its construction and operation.
Here are two videos that describe the challenges faced by bolted joints.
When you see that piece of heavy equipment, man lift, or structural application, you can be assured that the engineers have evaluated the risk.
For those of us in manufacturing, these are great tutorials to stoke our “Mastery of our craft.”
In maching, bolting that secures our tools and fixtures is subject to the same challenges as shown in these films.
Hat Tip to Jeff Remaley of Motch and Eichele for the find.
Do you have a favorite video explaining some aspect of engineering, machining, or manufacturing? Send us a link  in the comments so we can share it.

Seasonality explains our drop in Sales this November, as it does every year.
november 2015 BT
The November 2015 PMPA Business Trends Report Sales Index came in at 108, down 11 points from October, and virtually at the 12 month moving average of 108.8. The indicators that declined, Sales Index, Hours of First Shift Scheduled, and sentiment for Employment are explained, we feel,  by seasonal, rather than market weakness. The factors that improved, and in some cases improved markedly, include sentiments for Sales, Lead Times and Profitability for the next three months. With 44% of shops scheduling First Shift Overtime, the argument that the market is weak is not convincing.
Seasonality explains our drop in Sales at this time, as it does every year.
season red ball
Full report

The Institute for Supply Management   Purchasing Managers Index (PMI) for the manufacturing sector dropped to 48.6 in November from an October reading of 50.1. The reading, below 50% indicates contraction. This month’s reading  was the lowest since the end of the Great Recession in June 2009.

Manufacturing contracts for first time since
Manufacturing contracts for first time since

The employment index was at 51.3%, up from 47.6% in October, and the new orders index was at 48.9%, down from 52.9%.

The only good news for manufacturing in the ISM release was Manufacturing Employment and Raw Material prices:

  • Employment Index registered 51.3 percent, 3.7 percentage points above the October reading of 47.6 percent.
  • The Prices Index registered 35.5 percent, a decrease of 3.5 percentage points from the October reading of 39 percent, indicating lower raw materials prices for the 13th consecutive month.

Among the manufacturing markets that contracted in November according to the ISM report:

  • Fabricated Metal Products
  • Machinery
  • Primary Metals
  • Electrical Equipment
  • Appliances & Components
  • Computer & Electronic Products

The PMPA’s Business Trends Report for October came in at 119 for October – down two points from last month’s 121, down 12 points from October 2014’s record of 131, and interestingly, exactly the same value as the average for October for the past five years – 118.8 or 119. Our report also showed expectations for employment leveling off in October.

PMPA October 2015 Business Trends Report

Graph Courtesy Calculated Risk Blog