No no no, the axle part of them.
Where did anyone say the axles weren’t made of steel?
The only parts mentioned prior to your first post were the side effects themselves.
A bi-metal yoyo in my opinion is a yoyo with a different (usually heavier) metal placed near the rim of the yoyo. As has been previously stated, different metal components doesn’t necessarily mean bi-metal.
My 2cents.
It’s a paradox. Say you have a pile of sand, then you remove one grain of sand and it’s still a pile of sand, remove one more grain and it’s still a pile of sand, keep doing that in the end you will end up with a pinch of sand. The question is, when exactly did it turn from a pile to a pinch?
You can ask similar thing with a bi-metal combination, as long as designing goes you can make the rim big enough and the base small enough that it will become side effect, but when exactly?
It’s an undefined question and the answer is subjective, just like the pile of sand.
I still think that would be a plastic metal hybrid.
A very fine one indeed.
If you’re saying what I think you are, then that would be a very interesting concept.