I took apart my Axiom and DM and then combined it, i was supprised at how good it worked, even thought the Axiom is alot smaller, try combining them.
I seriously don’t believe that a weight difference of 2.5 grams from half-half can play good. And the Dark Magic has more rim-weight than the Axiom. This is bound to get really off-balance. I think the reason these ‘combined’ yoyos play good is because you just get a kick out of actually playing with two different halves.
well i think its pretty cool yes, i know the weight ratio is different, but it plays good and its fun in my opinion.
I have done this a few times, and even though some might be weighted differently, they almost always work quite well.
I combined a xconvict and a minimotu once, and I loved it.
Not really something that would become your main throw, but very fun to try for sure!
J.
Try doing half Superstar half M1, its fun 
DM and legacy work well together
Speedmaker and kickside!
Half M1 and Half Skyline work best for me.
I would imagine because the Legacy is based off of the DM…
I’ve tried Hayabusa + Velocity. It was tight
You can do it with any Yo-Yos.
BigYo 2, and Mighty Flea. 
Imperial and L3!
Yes people, I know it would be very hard to do. No comment plz. ;D
You actually can’t do it with any yoyo. The axle of either one of those yoyos won’t thread into each other.
888 and PGM!
I know. Thats why I put the:
But you also said you could do it with any yoyos.
This experiments has limits since different companies use different axles. One time, a person tried screwing an M1 and a Dv888 together. The M1’s axle got stuck in the Dv888. So he had two M1 halves without axles and two Dv888 halves with different axles.
Well you can do it with any Yo-Yo.
It would require modding, but it’ll work.
Then we are talking serious modding. Like actually remaking the axle/nut design on yoyos. This gets seriously hard if you move on to metal yoyos with hubs or spikes covering the axle. Or a Stargazer with a completely flat hub-area. And try to do it on an H2O (or an Oxy) with a very special axle design. And then try it on a Shield which has a similar axle design to the H2O but it’s glued.
Yes you might be able to do it on any yoyo, but I highly doubt that it’s possible. And if so, people won’t try to mess with rare metals to accomplish something like this.
Addment: Pretty shallow statement. Shallow and pedantic (don’t know what this means, took it from Family Guy).
It isn’t a might, it’s a can. It can happen, but like you said, serious modding. 
So you think it’s possible to remake the axle design on an H2O even though it uses a really unique axle design covered by a hub and being made out of titanium at the same time?
Addment: Yes I am fully aware that you can just take the half without an axle, but it will still be hard when you try to do this with a full titanium yoyo with a titanium axle.