If you’ve reached the point in your build where you are attaching fairings, interior panels, or wheel pants, you probably have a lot of brand-new nut plates (often called plate nuts, but this is what I learned to call them many years ago, and early learning is hard to undo … ) that have never seen a screw before. Nut plates, by design, have their threads squeezed slightly out of round to secure screws so they won’t back out. But this makes it very easy—when the nut plates are new—to gall (or even break) the first screw inserted into the nut plate. For this reason, I recommend two things to the inexperienced builder. First, never install a stainless steel screw into a new nut plate. If you want to end up with all-stainless hardware on your airplane, buy some steel screws and insert them first to “season” the nut plate. Then remove the steel screw and insert your stainless hardware.
Second, lubricate your steel screws with a little wax before inserting them. You can use the best—BoeLube—or just get a block of paraffin wax used for canning fruits and vegetables from the grocery store. My block of paraffin has been with me for decades and has melted into a lumpy shape by being stored in a hot shop on occasion. Doesn’t matter—just scrape the threads of the screw across the wax to load the threads up with a little paraffin, then insert it into the nut plate. The wax won’t run like liquid lubricant, so it won’t contaminate your soon-to-be-painted surfaces. A block of wax will last a lifetime, so use it generously!
I put a dab of wheel bearing grease on mine. The main reason is that I always have a can of it in my shop. And it is thick and resistant to both heat and water so it stays put and prevents the screw from rusting in place. It may not be optimal, but it has worked well for me and is cheap and already on hand.
Great article, but don’t forget the screw driver tip. I use a good brand (Apex) ACR replaceable tip for building as much as possible and save my (more) expensive screwdrivers for places where the tip with adapter will not fit. This reduced my phillips head damage by 5X. Always “size” your nut plates with a steel screw before using stainless screws as stainless will gall more easily.
Wax also works great for lubricating hinge pins, such as are used to secure cowls. I stole one of my wife’s candles for this purpose a dozen years ago, and she never missed it.
A toilet wax seal ring will also lubricate a lot of screws (a new one, not used……)
I’ve had a really small quantity of beeswax that I;ve been using for woodworking, going on 30 yrs so far. I Also use it for my Mooney screws.
I have never used wax, I always put a drop of ACF 50 on the screw with a new nut plate.