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NanciL's avatar
NanciL
Explorer II
Dec 28, 2017

Drilling holes in the TT's frame question

I am going to be drilling some 1/2" diameter holes in my trailer frame ,(the I beam) for some eye bolts for hurricane tie downs.
My question for any one that has done this or drilled through any steel is ; Would you first drill a smaller diameter hole, or go right at it with the 1/2" bit?

Jack L

23 Replies

  • I agree I would NOT drill into the frame. Some kind of clamp would work in a moderate storm but .......

    Hurricane tie-downs ? I'm not so sure it will really work in a Florida hurricane , you're probably wasting your time. People know when hurricanes are coming. If it were me , I would hitch up and vacate the area days before....don't wait till the roads clog.
  • Absolutely. I had to drill 12 or 16 1/2 holds when I put in frame reinforcements. We did each of them by stepping up from smaller to larger sizes.
  • If it were me, I'd avoid drilling 1/2" holes through the frame I-beams. Others will likely say the same. I'd consider some sort of beam flange brackets similar to the photo below. Could be a manufactured one or something you make yourself (if you can weld). Google "beam flange bracket" for ideas and sources. Easier, faster and non-invasive.

    From a structural engineering point of view, you should be fine with drilling 1/2" holes. (Look at the huge hole they hack out for slide mechanisms.) Keep the holes in middle 1/3 height in the vertical webs of the beams, preferably in the center and sufficiently away from any existing holes. For steel beams in buildings there are industry standards for where openings are to be in steel beams. You could google that too for ideas. I'd stay away from the spring hanger areas as that is a high stress location and in some cases is where fatigue cracks occur.

    For drill bits, maybe start with say 1/8" and then maybe 1 to 3 consecutively larger diameters. A 1/2" cobalt bit might be a good choice. Bits need to be SHARP! Use low drill speed and a little oil. A step bit should work okay too.