I'll second Garrett's, I have two old Garrett "Coin Hunter's" that were great machines. I've been talking about sending them back for recalibration for a while now. They are 70's machines and have been in the closet for years, they may work fine as is. If you found one at a yard sale or on Craigs you could probably get it for a few bucks, and they are top notch still. I don't like the security wands because I work for UPS and we have to go through a metal detector and get scanned leaving the building every day. I've quit emptying my pockets because they miss coins, belt buckles, and most of the junk I carry. The foil in gum wrappers drive them nuts, a little piece rolled into a ball in the bottom of a pocket will tie you up forever trying to get out.
My machine of choice now is a Fisher, but it's way over kill for hunting nails in a log. It's waterproof to 250 feet below.
My Fisher has a belt clip and a little hand held handle for the wand for hunting on the bottom while diving. You could make one for one of the Garrett's, and do away with the bulky wand, Joe.