Kevin have a look at this thread on the same subject **LINK** all the info is still pertinent to your question.
However as a matter of interest a pal who has an 1st generation Super 7 which he re-furbished, very successfully, asked me about regrinding the chuck jaws – well the chuck was in a sorry state and IMO would never have been very good so ho bought a Sanou 100mm 4" at a very reasonable price and it was indeed excellent for the price. But it is still well worth considering a purchase from one of the advertisers on here so if there is a problem you will undoubtedly have the problem solved – not easy or even impossible from China !
Cheers John