I've got a very study Richmond 5" dividing head that I've converted to run on the very useful Divisionmaster (designed by Tony Jeffree, sold by Lester Caine). A 5" dividing head is a hefty lump and the problem that I've encountered is that if I use the dividing head with a tailstock to support longer jobs there's very little milling table left for the workpiece.
I was contemplating converting my 6" rotary table to a stepper drive and using that as the dividing head with a suitable tailstock. This will free up about 12" of milling table. If I replaced the dividing head entirely with a converted rotary table are there any downsides?
Buy a little dividing head, by the time you have set the rot table up as a dividing head, cobbled up a tailstock you will be in the same mess you are now. Or as has been said, buy a bigger mill.
oNLY THE FACT THAT YOU CAN'T TILT AND ARE ALWAYS WORKING PARALLEL TO THE BED. Another disadvantage is that caps lock often gets stuck.
Since it's a Maho with a universal table then there's no disadvantage.
A bigger mill is not what I want or need!
Once you have the DivisionMaster you don't need a dividing head. So I don't see any downside ... only the upside of not miss counting rotations on the dividing plate. And converting the rotary table is relatively easy ...