yea, that'l work, idealy, the thread would be part of the shaft as id doubt the threaded bar would have the same strength, but you should be fine. have you limited the stroke? could you not maybe find an off the shelf ram more suited to begin with. the rams we use dont need honed either as they work by displacement. just an idea, no point giving yourself extra work.
and by the time you've adapted all this and run about, are you realy saving much over buying a rayvern (or similar) ram at around 100quid each designed for the purpose?
100quid each per ram £400 before i even start buying other stuff.. not really summin im prepared to pay when thease work perfectly to be honest the rayvern rams arnt much different any way

pretty much what ive done wouldnt u say.. id say mine are slighty stronger
responce yea, but you wouldnt use 4 of them rams on your average car, only the front. just saying by the time you've bought your ram, machined it, honed it, limited the stroke (which you will need to do to combat the side load) and run about after it all is it worth doing? not nessecarily saying rayvern rams, but with what your having to do there you'd be as well having a batch machined from scratch.
years ago i would have done shit like that to save a few quid, but fuck it, if your selling them to sum1 else, just buy the right thing and charge em the extra few quid, get your money for doing nothing rather than wanking about