the cartridge bearings are press fitted and they also keep the axle in place.
You'd have to tap them out to replace the axle.
However, have you bothered to see if the axle is hollow all the way through? Because all you'd have to do then is take a hacksaw and lop off the rest.
that's what I did with with my novatech hub.
That will likely work. Just leave 4mm extended out on each side. Be aware that checking your dropout alignment wouldn't hurt - these literally are the weakest darn hollow single speed axles out there - even a granny with a 15mm wrench can easily snap those things via the current mounting nuts. Test with a QR rod first - if it fits smoothly - then have at it.
=8-)
__________________
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life