# Making a hinge for my trailer ramps



## dave_r_1 (Sep 4, 2018)

I've made the main parts of the ramps.  Each section is 40" wide, 36" long, to make 2 folding ramps mounted adjacent to each other.



Right now, the equipment I have is all under 1,100lbs, and it's unlikely I'll be getting anything over 2,000lbs anytime soon.

I have some steel tubing (1" o.d., 5/8" i.d.) and then 5/8" steel rod to make the hinges with.  The basic plan is to weld pieces of the steel tubing along the folding edge of the ramp sections, stick the 5/8" rod through them, then something to keep the rod in place.  For each hinge (one hinge on each side of each ramp, so 4 hinges total), I was thinking of using 4 pieces 1-1.5" long steel tubing, alternating between top and bottom ramp sections.

My primary problem is I'm still not a particularly good, inexperienced welder, and trying to weld the pieces of steel tubing in the right place, so it folds without binding, and doesn't fold at a slight angle so it interferes with the adjacent ramp, and in just the right spot so the ramps are nice and flat when extended is, uh, very unlikely.  The primary issue is when really welding down the steel tubing, it'll shift a bit, and each section will shift a little bit different and so the hinges won't work right.

So, my plan of attack is:

-weld a long piece of steel tubing to the edge a strip of 1"x.25" flat steel (say, 24" of tubing to 24" flat steel)
-cut this assembly into 1.5" hinge pieces
-tack the 4 end hinge pieces into place (welding the edges of the flat sleet to the folding edge of the ramps, with the 5/8" rod inserts so they are aligned right, and then make sure the ramp folds right before welding those hinge pieces down
-repeat for the other 4 hinge pieces for that ramp, and repeat for the other ramp

The folding edge on the ramp sections is 1.25"x0.125" square steel tubing, which is what I would be welding the flat steel part of the hinge pieces to.  I figure I can weld the flat steel to the square tubing so it stays in place without moving significantly.

Does this sound like a reasonable plan for success?


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## dave_r_1 (Sep 4, 2018)

And this is a Q&D sketch of the end view of a hinge:


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## Cadillac (Sep 4, 2018)

Looks like you have it pretty well thought out. Only suggestion is trying to incorporate some grease zerks on the pins. Drill and tap pin for grease zerks then drill holes to distribute the grease to the hinges. 
 I had to build a set of ramps for my 20’ trailer. Basically lined up ramps in the up position with hinges welded to ramps squared already. When positioned tack weld all your points then check pivoting action. Once happy then burn them in. 
Only thing I wish I did was follow through with some intigrated lift springs. Already has some springs but lifting 100# ramps gets old really quick. Good luck.


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## Scruffy (Sep 7, 2018)

I’ve lived on a farm my whole life. Been around a lot of trailers.
My advice is make the hinge pin at least .250 thou smaller than the female part.  Dirt, rust ramps get tweaked a little, a little slop is nice.
Thanks scruffy ron


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## dave_r_1 (Sep 9, 2018)

Not sure what you mean there, because .250 is 1/4", which is a ridiculously large clearance, and .250 thou (1/4 thou) is, imho, a little tight.

Initially, I'll get it so the pin can easily slide by hand in the hole, and then when it's together, see how it folds, and if there is much difficulty, I'll take a bit off the pin and test again.


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## dave_r_1 (Sep 9, 2018)

Finished making the hinges and welded them on.  They turned out reasonably good, there is a little flexing in the middle of the ramp, one folds very close to evenly, the other folds over a little more than 1/4" out.

These are the hinges for one of the ramps.  I welded a tube twice the length shown, to a 1/4" flat steel, then welded the support braces in place (design change, to reduce the likelyhood of the weld of the tube to flat steel breaking, or the flat steel bending slightly when the ramps are used).

Also, the tubes are slightly too small for the 5/8" rod to fit through, and even drilling one out with a 5/8" bit, the rod didn't easily fit in it.  I had a 9/16" rod that did work very nicely.



Welding these hinges to the ramps was pretty straightforward for not have a proper welding table to line up the hinge parts and clamp them down.  I just had the garage floor with a large enough reasonably flat area, clamped the center supports of the two ramp halves together,  eyeballed the rod so it appeared to be along the split point between the two halves, then welded the hinge parts to the center supports (square tubing, in the earlier "design" image).  I did put a 1.5" support at the end of one ramp halve, so it was "folded" a little bit, as I knew there would be a little slack in the hinge when it is welded down, and if the ramp was flat when the hinge is welded down, then it would go a little past flat when it was used as a ramp.





This shows the offset due to the hinge being slightly misaligned.  I find it's non-trivial to get the hinge parts to be positioned right so when the ramp is unfolded, both sides touch so the ramp stays flat, and when folded, it folds right in half and not at a slight angle.  This shows the 1/4" offset when folded.  The other ramp didn't have this offset.



I think this turned out pretty well for me, doing the hinges this way, it would have been much more difficult if I had tried to weld that tubing directly to the center support.

But, I won't really know how well this works in practice until I get them on the trailer and run equipment up and down them a bunch of times.


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## dave_r_1 (Sep 9, 2018)

Oh yeah, I had planned to use 8 hinge parts on each ramp (requiring 16 to be made in total).  But, it's quite the hassle making those small support pieces, so I just went with 4 parts on each ramp.  I'll see how the ramps flex with equipment on the them, and if they flex too much, I'll make more parts and weld them on to provide more support.


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## dave_r_1 (Sep 9, 2018)

And naturally, now it hits me, instead of making those 8 small braces, it would have been both much easier and much stronger to just weld another strip of flat steel along the tube, going to the end of the bottom piece of flat steel, forming a triangle.


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## Cadillac (Sep 9, 2018)

Looking good. The hinge will be a lot more durable if you make 6 pcs. So the bushings can’t twist or pull apart with weight. So you would have two bushings on one side and one trapped between the two for other side. That keeps the ramps from wanting to go side to side.


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## dave_r_1 (Sep 10, 2018)

Took Cadillac's advice and made 4 more hinge parts:




Didn't go a good job welding in the V (inside the triangle, between the bottom flat steel and the tube.  Got a big wad of weld material that looked not terrible, but didn't penetrate into the flat.  It'll still be strong enough, as the primary strength for holding the tube in place when the ramp is extended is the flat angled part, which does appear to be decently welded.



Unfortunately, when I welded these bits onto the ramps, both ramps bind  when they are almost folded in half.  I'll probably spend some time later looking at why they are binding and how it needs to be altered to fold all the way.


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