Here's a book I've been using for a long time , at work and home , that I've found very helpful . It's title is Pocket Ref / last known publisher Sequoia publishing , Inc. . It's full of references from plumbing , carpentry , mechanical , conversion charts and everything in between . It also gives mathematical formulas for these topics . It's saved me several times , I hope it will do the same for ya'll . OBTW it,s only about $10 bucks .