MIMF

I am working on a piano which has a lot of rust on the screws.

To get the dampers off, I have to use a small vise grip to loosen the screws.

These are hardened steel screws set in wood.

Does anyone have a suggestion as far as placing oil on these or something else to help loosen these?

Try heat. Get yourself a big old fashioned soldering iron with at least a 1/4 inch diameter tip. Clean the screw and iron. melt a little solder on the tip of the iron for good thermal contact. heat the screw till it gives up. When replacing the screw coat the screw with a little bees wax. I use bees wax whenever I put in a wood screw.

Thanks!

Heating the screws definitely helped loosen them.

I put a little mineral oil on the screws after ward, and ran them in and out a little, which made them functional again.

I suspect the heat causes the wood to warm, and it is a little loosens due to the change in the size of the hole as the wood enlarges. Of course, I could be wrong!

Wood has lignin, it is the stuff that holds wood pellets together. Wood pellets are formed under high pressure and the process generates it's own heat. Enough on pellets. Along with a little rust the lignin would bond a wood screw to the wood. A little heat could release the lignin bond leaving the rust. This is only how I see it, I could be all wrong. In general a little heat helps loosen almost anything.