Sunday, June 13, 2010

Win Win . . .

With the decision to do it right the second time around and make use of the winch I had originally bought for the purpose (and I'm still not sure how I got sidetracked the first time) the pivoting framework was not really necessary. I could have just hooked the winch to that I suppose and although it would work (in theory) it still had it's disadvantages in that the geometry meant that it required very high pulling forces at the bottom and the top ends of the arc. It's main advantage was that it positioned the wheel exactly over the studs as it swung into position - time will tell how valuable that attribute is.
So take it off and remodel it to it's new purpose.
I never liked the two plates just welded onto it so that it could be bolted into position. But as we all know you can't just bolt through a piece of tube and not have it collapse as you do up the bolt. There are a number of other reasons why this approach is not good but just let's say there is a better way.
The end of the tube is rounded (more in a minute), two large holes bored through the tube at a distance to match the bolt holes


















and steel plugs turned up the same diam. as the holes


















and of a length so that they fit flush when the plugs are inserted in the holes


















Some flat bar the same width as the tube is then rolled around some bar


















so that when a piece of the right size is cut off it fits neatly around the end of the tube. The whole lot is then welded up. This is a messy business as it is welding through the zinc plating on the tube (which vapourises and is toxic and also deposits on the welding nozzle but is quicker than grinding all of the zinc off first - you never quite get it all anyway . . .) but if you turn the welder up you get a nice burn through with plenty of penetration - which is what you want as


















the next step is to grind off all the weld metal off the surface


















give it all a quick polish ready for priming and painting


















and a trial fit back on the truck to make sure I got it all right.


















I think that looks much better and I can do up the bolts to the correct tightness without fear off the tube collapsing.
Now on to the actual hoisting beam . . .
Similar principles are used to close up the end of piece of square tube. Thanks to good old Pythagoras if you leave the tab on the top of the tube 1.414 times the width of the tube it will be enough to close off the end without having to cut another piece to fit. Just bend it over


















and weld along the edges. I find it better to finish each section as I go rather than try to bend it all the way round before welding.























Bend the next step























Weld that up too and grind off all the rubbish




















Then weld on some side plates which carry the bolt through the middle of the pulley


















At the other end add an upright support bar to extend down to the wheel support bracket and some more side plates for another pulley.


















Next my least favourite bit (not the least because I hate heights) is to get up on the top and drill holes for mounting the hoist beam. Again these have "rivnuts"into the roof support tubes
















and stainless steel "T" washers with liberal amounts of silicone. I am paranoid about water penetration!














Next I need to make a bracket to mount the winch . . .

Meanwhile . . . after the last excursion . . . I was pleased with the way the electrical system worked. Using the microwave for some defrosting, lights and the air conditioner for an hour or so (reverse cycle) pulled the batteries down to 94%. I am hoping to keep them above 90% to avoid shortening their life. As they are mil-spec batteries they are not cheap (at about $7000) so you don't want to abuse them! A few hours of sunshine between rain showers and they were back up to 100%! Of course driving anywhere will charge them up in no time at 100amp input. All of this is good as I have not been happy with my generator situation. The generator is of course a new Honda and works perfectly - it's just that I was too enthusiastic about generator capacity and it is really just too big to go into the space I provided for it. If fits all right but there is no room for the extra sound and heat insulation I wanted to fit. Also the first trip proved that a smaller generator would suffice. In fact I never even took it with me! So - I hate buying and selling things second hand. I know some people revel in it but I can never even seem to break even. I decided to take a trip to "The Honda Shop" to see what was available in a slightly smaller version. Lo and Behold they now make a 3Kva which is smaller, lighter, quieter, runs longer on a single tank, cooler and of course . . . costs the same amount of money as the 6Kva that I had bought 18 months ago. They were quite intrigued with the fact that mine had done only 3 hours running (mainly to keep the battery charged) and was in perfect condition. Given that mine now cost new another $2000 more than I paid for it there seemed to be some maneuvering room. They could give me a brand new smaller unit (at their cost to them as a dealer) and sell my old one as a "demo"unit "$1000 off" and make a double margin. They only had one unit in stock but that was fitted with a remote start option and as I really wanted one anyway I said I would pay them for the remote start if I could take it then and there. I didn't want them to change their mind while waiting for another unit to come into stock.


















And there is the added benefit that I get a new warranty all over again . . .

Win - Win!

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