I have three london pattern anvils. The smallest at 45 lbs is truncated, the heel was broken off. My boys have used a 16lb sledge on it with no detriment to the anvil. I have three diy anvils that I use for my heavy sledging. One is a 5" x5" x7" block of annealed s7 at 65 lbs, anouther is a 5" x20" round hydraulic hammer head from an oil drill about 120 lbs s5 steel, the final one is two forks off a forklift that have been cut and welded back to back its dimensions are 4"x 8"x25" weighing in at about 230 lbs they are supposed to be 4140 or 4340 or something similar. They all move metal without difficulty. I paid less for all of my diy anvils put together then I did for one of my london pattern anvils.