Sometimes, a lesson learned from long ago comes to pass.
Recently I was working on a project that required I transfer the location of four threaded holes to a piece of aluminum so clearance holes could be drilled. The question was, how to do it?
Sure I could measure out the holes, but the threaded holes were t-nuts pressed into plywood, and the holes for the t-nuts were measured using a tape measure. So the hole placement was made to more of a carpentry accuracy than an aerospace tolerance. But I still wanted to keep the clearance holes as tight as practical.
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| A 3D model of the T-nut that was pressed into Plywood |
But I remembered watching an old tool maker when I was a young engineer fresh out of college. And if you haven't guessed by the title of this post, that was about 25 years ago.... Ouch.
He showed me a "threaded hole transfer punch". It's a small tool that stores threaded screws that look almost like set screws. However they have points in them instead of the hex that one would expect from a set screw.
I had my solution! I placed an order with McMaster Carr for the punch I needed, and I had it in my hands the next day.
They're screwed into the holes you need to transfer. You then position the workpiece that requires the holes, give it a quick strike with a hammer. And now you have marks where you need to drill.
Then it's off to the drill press to drill the holes you need.
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| The transfer punch tool and two of its inserts. The inserts are stored inside the tool. The tool also doubles as a wrench for the inserts. |
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| The transfer punch with two punches threaded into the T-nuts |
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| The marks left in the aluminum from the punches. I'm afraid I didn't get a chance to get a picture of the drilled holes. |
Using the tool that old die maker showed me, in the way he showed me how to use it, I had the holes I needed in no time flat. The whole process took about fifteen minutes. And that includes walking to another building where the drill press was kept!
That's a lot quicker than trying to match the holes by measuring it out.
And, in a strange case of deja vu, a young intern looked over my shoulder and asked me, "How did you mark those holes?"
So it was my turn to pass along the lesson I learned 25 years ago from an old die maker about the "threaded hole transfer punch".
Other than sharing a cool story, what's the lesson?
I would say to look for those small mentoring moments that can sometimes come from the most unexpected places. It might be from someone on the shop floor, an analyst in the corner of that dark office, or a program manager who's "been there and done that".
A lesson can be learned in a few minutes can take years to pay off. But when it does, it can be a life saver!
Wow, that lesson was twenty five years ago.... Thinking of that I'm suddenly overcome by the urge to yell at some kids to get off my lawn....
About the Author:
Jonathan Landeros is a degreed Mechanical Engineer and certified Aircraft Maintenance Techncian. He designs in Autodesk Inventor at work, and Autodesk Fusion 360 for home projects.
For fun he cycles, snowboards, and turns wrenches on aircraft.
