While doing routine maintenance on my enclosed trailer I noticed that several of the screws holding the sheet metal on the exterior were loose. As shown in the picture below they have an 8 point head. As some of you may be aware these are NOT Torx head screws (5 point star). In searching and researching for a correct bit to use to tighten them I discovered that the 8 point bits are of limited availability and quite expensive, however it turns out that a Robertson #2 Square bit works quite well and in fact many companies refer to the 8 point as a "double square" which refers to the fact that if you strip the initial placement of the bit you still have an alternate location to use. Several trailer manufacturers actually use the #2 square since it is much less expensive. Even though some of you may be aware of this I thought I would pass it along on the forum for those who may be frustrated with trying to find an 8 point bit. Also a good reminder to check all the screws for tightness on your enclosed trailer.
Note #2 square bit in 8 pt screw head.
On the curb side of my enclosed trailer - this is an ongoing problem.
The road vibrations cause the screws to back out.
I have noticed it most on the curb side as well. Usually is worse at the seams.
I think the correct bit for these screws is a torx bit. Might have this spelled wrong.
Torx drive screws are 6 lobed- not 8, hence the Robertson square bit works where as a Torx would not.
Dan is correct Jim. A Torx as I mentioned in my original post is not 8 point. It is 6. I just noticed that I "fat fingered" a 5 when I typed the original post. Should have proof read it better. Torx will not work on the "double square" (8 pt) screws.
Go to RV store and buy correct tip with 8 sides.
I've used Allen wrenches on them before.
Jim: When you do the tightening routine again, put a dab of clear silicone on the screw before you tighten it.
I my experience - nothing will keep sheet metal screws from backing out due to vibration caused by road conditions except stepping up to a larger screw size - on my front nose corners I use #14 self tapping hex head sheet metal screws.
I put mine back in with just a bit of silicone.
I wonder if a sealing washer like those used on a roofing screw would absorb vibrations and stay put. Never tried, just a thought.
Bill, that is a helpful hint. Several times folks have come into my store looking for an 8 point driver and could just not believe they hadn't thought of that when I suggested it. Kind of like a square nut in an 8 pt socket.
Haulmark trailers list replacement screws I noticed the other day, as well as square drivers. I wonder if a drop of red locktite would hold them. I replaced all of my screws a while back because of rusty heads, but they were and still are holding tight, after thousands of interstate miles. It is a Haulmark with a single torsion type axle.
Some deck screws are 8 point and they usually come with a driver in the box. Extra drivers are available at most lumber yards.