Machinist Transfers Skills to Repair Cracked Bolt Holes

Jo Mackiewicz of Howe's Welding and Metal Fabrication uses a Monarch lathe to fix cracked bolt holes, demonstrating how machining abilities carry over between fabrication jobs.

Published on Feb. 25, 2026

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In her work at Howe's Welding and Metal Fabrication in Ames, Iowa, Jo Mackiewicz has been tasked with repairing cracks in bolt holes on two separate occasions. To do this, she used a Monarch lathe to center-drill and turn pieces of round stock to fit exactly into the cracked bolt holes, allowing her to redrill the holes in the same location after repairing the cracks. This process showed how Mackiewicz was able to transfer her existing machining knowledge and skills from one project to the next, even though she still needed some guidance on certain lathe operations.

Why it matters

This story highlights how fabrication workers can leverage their existing skills and knowledge to tackle new challenges, even if they don't have complete mastery of every technique required. The ability to transfer learning is crucial for developing well-rounded competencies over time, rather than relying solely on specialized expertise.

The details

For the first project, Mackiewicz needed to repair a cracked cast-aluminum chain cover from a 1960s tiller. She center-drilled and turned ⅜-inch aluminum round stock to fit into the four cracked bolt holes, allowing her to redrill the holes in the same locations after welding the cracks. While Mackiewicz had some prior experience on the Monarch lathe, she still needed guidance from her coworker Heather, an apprentice machinist, on tasks like inserting the collet, setting the appropriate lathe speed, and adjusting the tooling height and angle. A few weeks later, Mackiewicz used the same round stock transfer technique to repair a cracked intake manifold, this time needing Heather's help with the lathe setup since the round stock was slightly larger.

  • In the last month, Mackiewicz has worked on two projects involving cracked bolt holes.
  • The first project, repairing the cast-aluminum chain cover, occurred several weeks ago.
  • The second project, repairing the cracked intake manifold, happened a few weeks after the first project.

The players

Jo Mackiewicz

An employee at Howe's Welding and Metal Fabrication in Ames, Iowa, who has been tasked with repairing cracked bolt holes using a Monarch lathe.

Heather

An apprentice machinist at Howe's Welding and Metal Fabrication who provided guidance and instruction to Mackiewicz on using the Monarch lathe.

Howe's Welding and Metal Fabrication

A fabrication shop located in Ames, Iowa where Mackiewicz and Heather work.

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What they’re saying

“Together, we center drilled the ends of two pieces of round stock and then turned each of the ends. By the fourth, I felt pretty comfortable with touching off the surface of the workpiece and using the automatic feed.”

— Jo Mackiewicz (The Fabricator)

“Even though we can identify the similarities between a prior and current task—such as a crack through a bolt hole—we don't necessarily yet have all the competences required to carry out the current task independently. Transfer is multilayered, including both conceptual (know-what) and procedural knowledge (know-how).”

— Jo Mackiewicz (The Fabricator)

What’s next

Mackiewicz will likely continue to take on projects that require her to transfer her existing machining skills to new situations, further developing her competencies over time.

The takeaway

This story demonstrates how fabrication workers can leverage their existing knowledge and abilities to tackle new challenges, even if they don't have complete mastery of every technique required. The ability to transfer learning is crucial for developing well-rounded skills and adapting to changing job demands.