@BeastMode2010: Mach Punch and Drain Punch are both useful. It's actually just sort of difficult to have Conkeldurr as a set up pokemon, especially with Flame Orb. Sometimes the best it can probably do is set up one Bulk Up and then attack if it is holding Flame Orb. With Drain Punch it might be able to afford to set up twice and attack to gain back health if it's faster than opponent, but without Mach Punch it will probably just faint to the next incoming pokemon.
So, either way, it'll be sort of hard with Flame Orb. With Flame Orb, you are probably better off with both Drain Punch and Mach Punch and just aiming to set up once. Of course there may be plenty of times where it will be able to set up two or 3 times, but you always have to prepare for the worst.