I want to put some hooks in my trailer for holding small items, not for securing loads. What's the approximate working weight of a self tapping screw say 1/8" in diameter screwed into aluminum about as thick? I'd like to hang my leathers and other small items weighing less than that and transport them while hung up on the wall. Examples would help if nobody knows the capacity. Thanks.
Static loads would be no biggie hangin leathers and such but I would worry about the loads generated while traveling down the road. Steel self tappers in to the steel support rails of the trailer should hold a good bit of weight. Aluminum not so much.
I think the thickness of the material you're screwing into is more important than screw loads. The thicker the material the more thread/surface area blah blah blah... If you're using them to secure brackets then you should be in good shape if you use at least 4 for a set of leathers etc. These opinions are not based on any sort of facts what so ever.
Remember that self-tapping screws need to be twice as long as the material they are screwed into (because of the taper on the screw), so you need to have room behind the plate for the pointy part of the screw. I don't like screws in aluminum, I would much rather use nuts and bolts. You can get #6 or #8 bolts with fine thread and the nuts are as thick as the diameter of the screw. Effectively the same room needed behind the plate for fastening as the screw, assuming you can access behind the plate. Probably not if you are investigating self-tapping screws. You could also have someone weld some hooks onto the plate for you, that's a great way to add parts and pieces to aluminum.
Just curious why you wouldn't want to use a shallow pan head self tapping screw into an actual hook. Then you know there wouldn't be any issues. And yes, I am a contractor.
depends on the type of alluinum dead soft 1100 series probley wont hold much. but higher grades 3000, 2024, 6061 and 7075 will hold alot. what is the part your trying to screw into? is it a extruded shape? c-channel, z-channel or a square tube. most extrusions are made out of a better alluiminum. the rule of thumb for tapping any hole is depth of threads needs to be 1.5 x diam. a 10/24 screw is .1875 in diam x 1.5 = .281 so the chances of a 10/24 failing in .125 all are pretty good over time. Sheet metal screws were made just for such applictions with there course pitch treads they engage more area for grip. as long as you dont leave heavy stuff on them going down the road you will get away with self taping screws just fine. the problem is not the weight its the repeated motion that will make it fail. just check them for torque every so often ( if there come loose they will probley fail)
Yep, the amount of weight you can hang off a machine screw is ASTOUNDING. Now a machine screw has more thread area, but a self tapper can hold a LOT of weight. Here's a hint: If you go to a restaurant with a ceiling fan that was installed prior to 1995 or so ( don't remember the exact date) the ONLY thing holding it up ( we're talking up to a hundred pounds here) is 2 # 8 machine screws or self tappers. But in aluminum with constant motion? I would hesitate to hang 10 pounds off it.
I see what you mean about the self tapping into aluminum. I'd be tapping into the square tube internal frame of an enclosed trailer. Unfortunately I can't get into the tube to install a nut or washer. What I might do is install 1/4" plywood where I can put a nut and washer on the back, then secure the plywood to the walls of the trailer with the self tapping screws. Welding sounds good but now you are talking $$ and not $.
I secured some etrack on the wall of my trailer using self-tapping screws into the steel frame. I think the screws are steel, whatever the trailer place gave me. On that etrack, I clipped in a metal hook and have been transporting my leathers on it for years. Hasn't fallen off the wall yet. It's probably a 3 ft section of etrack. Maybe that's working for me because the weight of the leathers is distributed over the 6 or so screws holding the etrack to the wall.
That and you tapped into steel. I don't think the aluminum in my trailer is going to hold up as well.
