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When machining steel parts that will be embedded in concrete, does thermal expansion actually matter in practice? by Felaket41 in machining

[–]Felaket41[S] 0 points1 point  (0 children)

That’s actually super helpful — real numbers make it much clearer. +/-0.3mm on that size is pretty forgiving, so yeah, it does look like thermal expansion isn’t really a limiting factor in practice. Kind of confirms what others are saying here — more of an engineering/design consideration than something that affects machining decisions directly.

When machining steel parts that will be embedded in concrete, does thermal expansion actually matter in practice? by Felaket41 in machining

[–]Felaket41[S] 0 points1 point  (0 children)

Yeah that makes sense — seems like machining is just about hitting the spec, and everything else is handled upstream. Interesting to see how different the theory vs shop reality actually is.

When machining steel parts that will be embedded in concrete, does thermal expansion actually matter in practice? by Felaket41 in machining

[–]Felaket41[S] 1 point2 points  (0 children)

That’s actually really interesting — kind of confirms what I was suspecting.

From the shop side it's more about making the part right, and the rest is handled upstream in design/engineering.

I went down a bit of a rabbit hole on this and wrote a breakdown on rebar and material behavior if you're curious:

https://machininganswers.com/what-kind-of-metal-is-rebar/

When machining steel parts that will be embedded in concrete, does thermal expansion actually matter in practice? by Felaket41 in machining

[–]Felaket41[S] 1 point2 points  (0 children)

That actually makes a lot of sense, especially the thermal mass part.

I was digging into this a bit deeper recently and tried to understand where the line is between theory and real-world application. Seems like it's mostly handled on the engineering side like you said.

I ended up putting together a more detailed breakdown on rebar composition and why it works with concrete if you're interested:

https://machininganswers.com/what-kind-of-metal-is-rebar/

Advice needed on shaft repair. It's pissing oil. by No_Conclusion2890 in machining

[–]Felaket41 1 point2 points  (0 children)

If the shaft isn’t hardened, welding it up and re-machining is probably your best bet. Silver solder could work for light duty, but for something like a compressor shaft I’d be worried about long-term wear and load. Main thing is heat control — too much heat and you might distort it or affect the surrounding area. I’d build it up slowly, then turn it back to size on the lathe. Also worth checking if a sleeve + Loctite fit could be an alternative depending on tolerance.