I have a PM 3520b.I may be in the market for the 18" extension.Any ideas on who offers the best price?I have seen shop made extensions, those of you who have made your own..are you pleased with the results?The college where i took wood turning,has 3 or more PM3520b's and all came with bed extensions...if i can't find one online ,i may contact the college.Any novel solutions, please post with pic's. Thanks Rob