White or black nylon washers work great. They hold up better than the softer plastic ones do. Black nylon (delrin) is supposedly self lubricating.

 

Thank You!!!

 

I'm 100% with Doug.

 

Jim; if they're lag bolts, there's no mechanical advantage to cranking them down tightly.
Leaving a couple of thou clearance alone will greatly reduce the friction. The wear on the arm-holes, and bolt shanks where they contact, might be a concern?

 

I'll be using a 3/8" lag screw......#8 if they have it. I'm not sure of the gauge of the arm or mounting plate metal but they are not thin or flimsy. The manufacturer connects them with a rivet. I've contacted the manufacturer and this type of wear is not an uncommon problem. I've seen some on-line blogs and a lot of folks seem to have encountered the same problem. One blogger was going to use a hex bolt and nylock nut to make the connection....not a bad idea but the bolt head would not be accessable if the nut ever loosened....so I decided to go with a lag screw. I could buy an entire arm assembly from the manufacturer but I figured I'd try this quick and less expensive fix first. This is for attic pulldown stairs which get very little use.

 

Depends on often you use the stairway. Mine has been in the ceiling for a bit over 20 years and not worn out yet. I am, though.
If the stairway has worn out the original hardware already, go with metal washers and lightly coat them with Vaseline. The plastic will wear out.

 

Using 2 or 3 metal washers works better than just one.

 

the lag is softer than the original rivet... it won't last either..

 

If it doesn't I can always buy the entire arm assembly from the manufacturer.

 

I had trouble with the real holder in a wire feed MIG welder. The wing nut would tighten itself against the spring that offered friction to keep the reel of wire from coasting during the starts and stops of the feeder. I tried several kinds of metal and plastic type washers. and all transferred enough friction to the wing nut that It would tighten. I finally has success with a grade 8 hardness washer. If nothing else works, try some of them.

Charley

 

I'm with John, go wit metal washers. Don't try to over think the problem, metal on metal will last for ever on something like attic stairs that are only puled down occasionally.

 

I'm done thinking!!!!! It's time for doing!!!!!!