Hello Frank,
I have to confess I haven't cut steel billets in that diameter so you are at the front of the curve this time. Having said that I have sawn 8 inch by 2 inch flame cut slabs on my saw, I took the vice right off and clamped things down to the base. a little ingenuity in mounting was needed but it coped very well, only one blade failure during the process. There were several cuts to extract the shape I wanted to get out of it.
More tips? Wel yes, I do have another simple tip which came to me yesterday but in the spirit of making it widely available I'll be offering it for inclusion in MEW.
Thanks again for your comments, nice to be appreciated!
Kind regards Brian