Wednesday, 25 July 2012

Ramping My Style

This may well be the final post of the trailer build, I finally got the MIG welder set up for ally a couple of weekends ago and had a stab at making the ramps.

The previous ramp design was simply to bolt a length of 40x40 angle steel down each side of the runners to provide some stiffness and weld in some cross bars to hold them together, if you have a look in the back ground of the photo's in previous posts you can see them kicking about. Unfortunately they this was nowhere near strong enough so a new solution had to be sought.

We decided that welding in two lengths of 50x50 aluminium channel using the lower surface of the ramp to complete a box section  was the way forward as not only would this give us twice as many vertical webs but they would be over 10mm deeper, the material was a full mm thicker and they would be forming not one but two hallowed box sections that were welded (not bolted) into place, something we were entirely lacking with the previous design.

I had one roll of wire and two small cylinders of Argon so after a mere six inches of practise welds on some off-cuts to get a feel for the right setting and technique it was time to go for it. Ill let you make your own minds up.

I must say I'm fairly happy with the results, for a first attempt they came out pretty good. aluminium behaves totally differently to steel, it's much softer so you use loads of wire and need a much higher wire-speed, it expands when heated a lot more than steel so you need to stay further away from the arc to prevent the wire getting stuck in the tip and the heat doesn't seem to sink into it in quite the same way. I think with more time to find the perfect setting and perfect my technique I could get some tidy looking welds. As it is, some were really good and some not so good and I don't have the experience yet to know why that is, even with the really good ones I was getting lots of spatter and not quite the same level of penetration I can get with steel but I think to do really good job of Ally you need a TIG welder and that's way out of my price range (yes I'm blaming my tools).

We also needed to devise a way of storing the ramps on the chassis when they're not in use. The runners and ramps are 400mm wide and quite by chance the space between them is just over 800mm so it was immediately obvious where they would be going, it was merely a question of thinking of a simple method of holding them to the chassis that allowed easy access with a car on board and didn't have them rattling around.

We decided on a nice, simple under/over lever set-up and over-centre clamps. Basically the ramps go under a bar in the middle of the chassis:

Over another bar that's slightly less than the the depth of the ramp lower than the first bar toward the rear of the trailer:

So a heavy duty stainless over-centre clamp can pull it tight against the bottom/top of each bar to hold it firmly in place:

The middle bar is a little too high which is why they don't pull neatly down to meet the chassis, this is because it was welded in before we knew the ramps themselves were going to need a rethink, but it's a simple enough job to chop it out and weld it back in a little lower. But for now they look great, can be easily loaded and unloaded, with or without a car on board and its all padded out with rubber pads so they don't rattle in the slightest, that's all the boxes ticked.

As you can see the trailer seems to be in a new location, that's because its at my folk's pace in north Wales but I think I'll keep that for the next post.

Thursday, 19 July 2012

More Finishing Touches

After some deliberation we decide to move the location of the brake return springs. They used to act on the rod that exited the drum itself (top center of the picture) but the rod that goes from the lever to the balance bar is threaded, so provides a much easier solution for giving the spring something to act on. Basically we cut a 70mm length of 25x25 box metal in half, diagonally and drilled a hole in the top of the thin end of each 'wedge'. one wedge was welded to the chassis while the other had the thick end capped off with sheet steel and a captive nut welded to the inside of it. This second one was then threaded up the brake rod into a suitable position so as to provide enough tension in the spring to ensure the brakes are pulled off, you can see a lock-nut acts against the captive one and holds it in place. I'm really happy with how this turned out, it looks tidy and works perfectly.

Return springs were a problem well solved

Another pleasant little task was the fitting of the number plate. I had picked up a swish stainless steel back-plate and some rather tidy LED lights from Ebay (£20 the lot, bargain). popping them on took no time at all and made the trailer look way more finished.

Next up was the rear light clusters, As I have mention before we needed to modify them slightly to make them detachable, and compatible with the loom I had purchased. The first job was to fix in the bolt that would pass through the ally bar that the ramps will hook over, a simple matter of drilling a hole in the bottom of them and pushing a bolt through the hole with a lock-nut on the opposite side, said bolt then passes through the bar and wing nut hold the light cluster in place.
To attach them to the loom was a little more involved a this required buying some water-proof DIY multi-plugs, and wiring our own piece of 7 core cable from the lamps and creating a water tight hole for it to pass through then chopping off the existing loom plugs and replacing them with our own. we also had to lay extra wires to account for the fact that the lamps have fog and reverse on both sides whereas most trailers only have a  have a fog on the driver's and no reverse what-so-ever

And there you go, all that remains now is make some provision the attach the spare wheel and get the welder  converted to ally so I can attack the ramps. I'm more than a little nervous about this as not only did all that aluminium for the ramps cost me about £200 but I've never welded ally before and if they fail its going to total whatever is driving up them at the time. No guts, no glory.