Chat GPT settled the debate over 6061 vs 7075. šŸ¤Æ

General Yo-Yo
21

it also ignores the greater anodic propensity of 6061ā€¦ but only because this has yet to be discovered.

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22

Itā€™s also worth considering the ā€˜knuckle impact factorā€™. 7075, being denser than 6061, has a higher KIF. I havenā€™t quantified this, and itā€™s solely based on personal anecdotal evidence, but I suspect the density prevents as much vibration throughout the yoyo when it strikes something, so more energy is transferred into the struck object and less is absorbed through vibration.

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23

Test it by punching aluminum ingots. I would also like to submit an alternate measure of Fingertip Impact Factor. Knuckles are indeed a victim of yoyo impacts but they are more sufficiently hardened against impact than fingertips. I feel the rare fingertip impact will yield more precise data due to less hardening.

24

Funny you say that as Iā€™m a metallurgist for an auto supplierā€™s R&D center. Unfortunately I almost exclusively deal in hardenable steels.

But you got me wondering, so I looked it up.

Hardness of 7075: 150 on the Brinell scale (500g load, 10mm ball) which is about 175 on the Vickers scale.
Hardness of 6061: 95 on the Brinell scale, which is about 105 on the Vickers scale

So 7075 is significantly harder than 6061. I figured as much, but I didnā€™t expect there to be such a large difference.

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25

Funny you say unfortunately when I think thatā€™s awesome. Very fitting job for also having a hobby where the items in said hobby are almost exclusively made of those materials when they are metallic. Granted itā€™s also probably stupidly hard labor too

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26

Interesting idea and while there may be some amount of energy thatā€™s lost to vibration (and heat) I think the ouch factor is mostly just (mass x acceleration) / area.

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27

Itā€™d make sense that thatā€™s the most dominating factor. But I believe that hardness, toughness, and elasticity likely play a small part.

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28

Density and elasticity especially. I would rather be hit by 63 g of styrofoam than 63 of aluminum

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29

This isnā€™t my science homework but it could be if I wanted it to be

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