Sunday, June 3, 2012

A Spatula Repair

This spatula has popped a fastening.[1]

With the thing clamped down at the edge of the workbench, I was able to do a pretty accurate job of centre punching the dome of the fastening.

Chrome-plated steel is hard, slippery stuff, so I started with a small, very sharp centre punch. Then I used a bigger, blunter centre punch to get a more pronounced dimple. Now I'll see how good a job I can do of drilling that through with a cobalt drill.

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It's not perfect, but it's close enough that I can make this work out.

I drilled that 9/64" diameter, which is slightly oversize for cutting an 8-32 thread. I'll grind away that protruding material, and see if that steel is mild enough that I can tap it. It wasn't too difficult to drill, so this may work.

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That turned out remarkably well.

I installed that truss head screw with red threadlocker, and tightened it really tight with a 3/8" square drive screwdriver bit. The screw's length is such that the end of the screw protrudes slightly from the spatula's shank. When the threadlocker has cured, I'll peen the screw's end over rivet-fashion, and that should be a permanent, long-lasting repair.

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Here's the end of the screw peened over.

That screw's not going anywhere soon.

So there we are. Come the collapse of the global economy, those of us who can repair a spatula will still be able to flip a fried egg.

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[1] I had a devil of a time coming up with what to call that peened-over fastening.

I'm inclined to call such things 'peens' or 'swages', but it seems that's not the done thing. The result of peening is not called a peen, nor is the result of swaging called a swage.

In Wikipedia's article titled "Rivet", I found the terms 'shop head' and 'buck-tail' for the peened-over end of a rivet.[2] (They appear early on -- at the end of the first paragraph.) Both terms were new to me, and I prefer to keep this blog relatively free of specialized jargon, so I settled on 'fastening'. If anyone knows of a better, more intuitive word for the peened-over end of a rivet, I'd like to know what it is.

[2] The factory didn't actually use any separate rivets in the spatula's construction, but the fastening method used is effectively that of riveting. The fastenings are the peened-over ends of tiny, cylindrical protrusions that are integral to the shank. It's amazing the difficulties one can encounter in trying to write about a seemingly very simple item.

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