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Can you use mild steel instead of spring steel?

My name is Helen, a second year BBS student. I have a query relating to the theoretical minimum no. of parts used in assembly of, what I can no better describe as a thingy (plate, bearing housing, 2 washers, 2 nuts and 2 screws). All parts are mild steel bar the plate, which is spring steel.

Is there any reason why the plate (1.5 thick, 60 in diameter) must be of a different material then the others? Does it have a particular property which makes it more, well, usable (for want of better words).

Thats about it,

Thanking you kindly,

Helen

Helen L.
student - Cork, Co. Cork, Ireland
2004

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2004

Unfortunately, I am ignorant of your school system, Helen, so I don't know what age a 2nd year BBS student is, or what grade that is equivalent to in the USA; that makes it difficult to answer appropriately.

I recall a definition of a pea as being an object which, if you had 28 quadrillion of them, would cover the earth to a depth of two feet. Your project seems to be of the type that creates such definitions. Spring steel provides a function, it springs. Whether that functionality is essential, optional, troublesome, or unacceptable to a thingy is, at best, difficult to speculate about.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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2004

When I bend a piece of steel a small amount and let it go, it springs back. If I bend it more, it'll spring back a little, but not all the way. We say it "takes a set". The point at which it takes a set, or more precisely where we go from elastic to plastic deformation, is related to the yield strength of the material.

"Spring steel" is a generic term for steel that has been processed, usually but not always by cold working, to achieve a really high yield strength. Hence it will be able to resist "taking a set" when you load it heavily- or at least more so, by a wide margin, than mild steel.

The downside of spring steel is that it will be less formable, less machinable, more brittle, than it's mild steel cousin.

Good luck on your studies!

Lee Gearhart
metallurgist - E. Aurora, New York

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Heating zinc plated hook screws in order to bend the hooks

Q. My wife wants a rack to lift the back tire of her bicycle so she can use it as a stationary bike. I want to try to make one myself.

Part of my idea is to take two zinc-plated lag thread screw hooks and open the curve of the hooks so the rear of the bicycle frame can rest on them. Can I heat them in order to bend them? Will I make the metal weaker? Is there danger of chemical exposure or something else I should know about?

Thank you for this website.

Sincerely,

Brian Miller
hobbyist - Parma, Ohio, US
March 31, 2020

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Q. Hr Mr. Mooney,

First of all, that's a beautiful picture of the two of you. Second, I'll admit I'm a bit of a cheapskate, but I did shell out the money at a big-box store and bought them.

Just to clarify the description of the hooks I bought: if you hold the hook horizontally, the hook part goes downward at a 45-degree angle, loops, then goes back up at a 45-degree angle. At this store, I didn't see any where the hook part goes straight down then straight up. If you know of any stores that have hooks like that, I'd be glad to hear from you. If you're not allowed to give the names of stores, I get it. Thanks for helping. Please try to stay healthy with this coronavirus crisis.

God bless,

Brian Miller [returning]
- Parma, Ohio, US
April 2, 2020