Drilling Through Metal - Part Deux

[mcspin50]

Back when I first started building my teardrop, I asked about drilling through the steel cross braces on my trailer here.

Now I'm trying to mount my 5# propane tank in its holder to the tongue of the trailer. This time I am wondering if it's possible to drill through the 2" x 3" steel member (top and bottom) without taking my arm off. I was planning on using 3-1/2" steel bolts to anchor it to the tongue.

Or is there another better way to mount it?

Tank in its holder...


Where I want it to sit...


Tank sitting in place...

[Nobody]

Lil, I don't believe I'd drill holes vertically thru the tongue, as you've indicated you want to do. Appears you've (or someone) already drilled a horizontal hole thru that member to attach the piece of angle holding the cabin. 2 Vertical holes, one directly in front of the horizontal hole, & another maybe 14" in front of that would only weaken the tongue further. Might not matter so much with the 'A' frame on either side but I'd not risk it myself. Instead, I'd devise or fabricate (or buy) a 'square' 'U' bolt that would fit the tongue pretty tightly, for each tab on the propane mount, & use those to mount the propane bracket to the tongue. You don't want to tighten the 'U' bolts so tightly that they 'crush' the tongue tubing, just enough to secure the tank in place. Or, you could devise a 'plate' to fit the 'A' frame members that you could bolt the bracket to using shorter bolts...

[DrewsBrews]

What is the trailer weight? Looks pretty overbuilt for the size so I'd doubt those holes would be a big deal.

[MtnDon]

The main issue with drilling through and bolting as is being considered is not really loss of strength from the hole. If you drill through and use a long bolt you can never really get the bolt tight. Tightening the bolt will crush / deform the frame member. It may feel tight but it can not be properly tightened because the box section of the frame deforms. The deformation of the frame will cause weakness.

A square ended u-bolt as was suggested is better, Best would be some brackets, whatever, welded to the frame with the tank bracket bolted to that. Or maybe weld the tank bracket to the frame, using a competent welder.

If a bolt through method is desired for whatever reason, there is a way. A tube needs to be inserted to prevent the crushing. That can be done by first drilling through top and bottom. Either the upper or lower hole in reamed out to allow insertion of a length of steel tube. The tube butts against the inside of the frame where the smaller hole is drilled. The tube length is made to be flush with the outside surface of the frame where the tube enters. A large flat washer helps distribute the crush force.

If it was me I'd weld the bracket to the frame member. Simple, strong.

[MtnDon]

dupe post removed

[Shadow Catcher]

I would clamp it to the frame rather than drilling.

[noseoil]

I agree about welding on a couple of tabs & not drilling the frame. You could weld a tab to the left at the front and one to the right at the rear (offset the bracket to twist it slightly) and then bolt through the tab to mount the tank. A couple of angle iron 1 1/2" X 1 1/2" tabs would be the way to go, simple, strong & secure, without compromising the integrity of the frame. 20 minute job for the welder, a little spray paint & it's ready to drill.

As far as drilling the steel, use a small pilot hole & some cutting oil first (1/8" or smaller), then step up until you get to the finished size hole you need. It's quicker & easier than trying to slam a large bit through all at one go, safer too.

[mcspin50]

Thank you all for your ideas! I *knew* there had to be a better way than drilling holes through two layers of steel. I'm going to visit the hardware store for some square u-bolts or brackets and if nothing seems to work, I'll go back to the welder who built the holder and get him to weld it to the trailer frame.

DrewsBrews..the trailer is a 5x8 no-floor trailer from Northern Equipment that I had the two angled pieces welded to the second crossbar to give the trailer more rigidity. We had bought another of the same one to haul the riding lawnmower. It doesn't have the angled braces (only the center tongue) and I can see that the two front corners have sagged. There's a thread about the trailer here.

Thanks again everyone!

[Redneck Teepee]

[quote="mcspin50"] I'll go back to the welder who built the holder and get him to weld it to the trailer frame.



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Your Best Bet.

[KennethW]

I would drill and use self tapping bolts. Just drill under size first so you don't go oversize.

[KCStudly]

I tend to avoid taping directly into thin wall tubing, especially for something as critical as a gas bottle. A thread insert (the rivet style) or welded thread bung would probably be okay, but would still add a potential failure point for the tube (... though probably not an issue with the extra A-frame members).

Still, the best solution is bolt tabs welded on, like MtnDon suggested.

[mcspin50]

For now, I've secured the tank holder to the 2x3 tubing with a square u-bolt. Seems to be very stable. Going camping this weekend to a nearby state park so will give it a trial run.

Thanks for all your help, suggestions, and wisdom.

[Prem]

Welding is always stronger and no holes to rust!

[vegask]

Welding is always stronger and no holes to rust!

I'd weld a bracket to the tongue if it were me. But I also despise drilling metal.


If you have to drill, use a 1/4" bit, low speed, and dip the bit in some oil every 15 seconds. It will take you a minute or two to get the first hole. Then get one of those high speed step bits to enlarge it to 1/2". Though 3/8 grade 8 bolts are more than strong enough for a propane tank. The steering box on my truck is held on with 1/2" bolts.

[Prem]

Well, yeah. Ya don't wanna weld da propane tank to da tongue of da trailer. Weld the mounting bracket to the tongue.