not just any tip will do theres a special one( #561). and dremmel should have that base that u rest it against what your cutting. free handed is very hard, and it wont come out straight..
if u wanted to know what i was doing , i was making a lightsaber from a pvc pipe, epoxy putty sintra and hot glue
if i do not cut the pipe it will be a very VERY long lighsaber
There is also a tool i use called conduit cutters, you can pick them up from electrical wholesalers or any large tool shop. They are great for cutting multiple pieces of conduit/coro without leaving a ragged edge, which hacksaws do leave.