Based upon the following description, Thron is not the equal to 853:
"Thron - Thron Tube Sets have lightness, rigidity, and a very good price / performance ratio. This double butted tube set can be lugged or fillet brazed. Its double butted wall thickness allow it to be an excellent entry level choice for both road and track. Very large selection of round tubes with different wall thickness and shapes allow the rider to build a stiff frame at an affordable price."
It sounds like it's probably closer to 631, not that that's a bad thing at all! I ride an old Columbus Cromor frame (lower than the old SL in the Columbus line) and love it.