Had a core shift scare on a big gear pattern last Tuesday

I was ramming up a 500-pound gear pattern for a steel pour at our shop in Toledo. The cope half felt solid, but when I flipped it to check the drag, I saw a half-inch gap forming along one edge of the core print. The core would have floated for sure. I stopped everything, chipped out the sand around that print, and re-rammed it with a smaller peen. It added an hour to the job, but the casting came out clean with no defects. Has anyone else caught a shift that late in the process? What's your fix?

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3 Comments

carter.gavin5mo ago

That's a drag shift, not a core shift. The core print misalignment means your mold halves didn't line up. Your fix worked, but checking alignment pins before ramming might save that hour next time.

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sam_thomas5mo ago

Checking pins is good, but what about worn bushings?

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rubys805mo ago

Yeah the part about checking pins before ramming... I used to just ram first and ask questions later. Wasted so much time chasing what I thought was core shift. Now I see how a quick check on those pins can show a drag shift right away. It seems obvious now but it took someone pointing it out for it to click.

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