Interseting comprison. Just on a market cap to sales comparison, Hammond's market cap is 32% of sales and PLPCE is 50%  of sales.
Hammond's operatng margin is 8.56%  and plpc is 6.84%.

Hammond's growth propsects are better. 

Any way you cut it,Hammond  stock is undervalued by at least 20%. ie share should be at $20. 
These are conservative numbers .