I was over-tightening my flask clamps for years without knowing it

Had a real lightbulb moment last Thursday when a new guy, Mike, asked why I cranked them down so hard. I always thought tighter meant less flash and better molds, you know? He showed me a flask I'd done where the cope was actually bowed in the middle from the pressure. We poured it anyway and the casting came out with a thin spot right there. Mike said his old foreman in Dayton taught him to go 'snug plus a quarter turn' and that's it. I tried it on our next run of 20 gray iron brackets and the flash was the same but the flasks looked way better after shakeout. How do you all judge clamp tightness, just by feel or do you use a torque wrench?

3 comments

3 Comments

the_zara13d ago

Honestly, how many flasks have I murdered over the years? Tbh I probably owe my old shop a whole new set of clamps. I was the same, just leaning on the cheater bar until my arms shook thinking I was doing it right. Felt like a real genius when I finally saw the warped drag on a simple gear blank.

theawest12d ago

My personal record was cracking a brand new flask on its first job. The sound was like a gunshot, and my foreman just slowly put his head in his hands. Took me a solid year to stop over-tightening everything.

julia84311d ago

Read an article once that called it "torque anxiety." You get so scared of a loose connection that you just keep cranking until something gives. The worst part is you can feel it getting tighter, but your brain just won't send the stop signal.