I don't have any current recommendation for a machine shop, but there is a product that I can definitely recommend. It's a penetrating oil called Kroil, made by Kano Labs. It works amazingly well on rusted nuts, bolts, screws, and will lower your blood pressure and reduce the number of swear words while you're trying to unfasten rusted hardware.
I had heard about this stuff on a firearms forum, and ordered both a spray can and a regular can, which may be a lifetime supply. You don't need much of it for it to work. About two weeks ago, I was taking the front bumper off of my '64 Nova, and the nuts on the bumper bolts had probably been in place for about 40 to 50 years, and were all pretty rusty. I fought with the first one for about half an hour, trying different wrenches and sockets, and not having much success at unscrewing the nut. I finally decided to try some Kroil on in, and used the spray can with a plastic applicator tube to direct the spray.
I sprayed all the bumper bolt nuts with Kroil, waited about ten minutes, then proceeded to unscrew all the nuts from the bolts with little or no effort.
You probably won't find this stuff at your local hardware store. I got the spray can at Tacoma Screw Products in Boise. I had to order the standard can on line, which may be the simplest way to buy it, because TSP stores are mostly just in the Pacific Northwest area of the country. Just Google Kroil, and you should be able to come up with a retailer to order it from. This stuff puts Liquid Wrench to shame.
I agree 100% with this statement. I have worked farm mechanics for most of my life, and this stuff is gold here in the wet northwest.
