Howmet (HWM) could be a solid addition to your portfolio given a notable revision in the company's earnings estimates. While the stock has been gaining lately, the trend might continue since its earnings outlook is still improving.The upward trend in estimate revisions for this maker of engineered products for the aerospace and other industries reflects growing optimism of analysts on its earnings prospects, which should get reflected in its stock price. After all, empirical research shows a strong correlat ...