Could anyone help me with this problem of mounting a fan without screw threads on my hyper 212+

I have a hyper 212+ with the default blademaster fan, I tried mounting on an additional CM fan(R4-C2R-20AC-GP) in the pull configuration for better cooling.

But i'm encountering problems screwing the screws provided in the 212+. The fan doesnt have any threads and the screws seem to be a bit large for it.
Am i using the wrong screws? or should i force the screws in, or thread the fan holes?