My Self-Build Drawbar Turntable Trailer

Conception/Planning

In 2011 we built our big trailer to carry the Ruston & Hornsby engine and provide us with accomodation at shows that we attended.

Much of the design and build will be of interest to self-build afficionados as nearly all the equipment and techniques carry across to motorhomes.

We still have the trailer and will be using it on the weekend 25/26th June when we go to a Land Rover forum get together.

Since buying another engine in August, we are building a second trailer so our son can come with us to the shows.

Peter

The Base Vehicle

In 2009 we attended the Essex Country Show at Barleylands near Billericay in Essex. We took our Ruston 1ZHR on its normal trailer, and because we couldn't take the caravan, we had to take a tent to sleep in overnight. It was an interesting experience! We had camped many times over the years, and still had all of our kit from the trips to Spain, but our ages were starting to tell, and we both talked about something better.



Various ideas were discussed, and I took some time while watching the engine at the show to think about what we could do. It was close enough to drive back each night if we wanted to, but other shows were not so convenient, and there were other considerations such as showers and toilets. Of all the shows we attended, only Nuenen provided decent showers and toilets for exhibitors, at all the other places you either brought your own or had a wash out of a bowl, in water heated in a kettle, it was that bad!

The following year we stayed in a hotel, and things were starting to gel in terms of what we needed, but we still hadn't really got the impetus to get started.

That summer, one of our Stationary Engine Forum members started a discussion on the subject of a drawbar trailer, and that was what got us off on the road to building our own. I had some sketches that I had made, and over the next few months I started to form a vision of what I wanted and started to draw it out properly. We have a CAD system available at home, so it wasn't long before I had produced a set of outline drawings of a 6-wheel turntable drawbar trailer, with housing for the engine in the back half and living accomodation for us in the front.



15/09/10

We started with a concept outline drawing, fixing the main dimensions, getting a feel for the mechanical layout and sorting out how much room we had available for us to live in. Another thing that was affecting what we were doing was impending leglislation in the UK for trailers. We understood that all trailers would need Type Approval, to be compliant with EC regulations, and that included home-built as well as commercially built.



We had at that time already bought new axles, wheels and tyres for a new standard 4-wheel trailer, so we had the basics already, we just needed to buy an extra axle and wheels. The body we thought could be done by a local coachworks, but we were to be disappointed on that score.

24/11/10

By November 2010 we had started to buy the parts needed for the construction, a 3.5tonne trailer coupling, the extra axle and so forth. The design of the chassis was well advanced by now, the front axle pivot having taken a fair bit of time to think through and draw up, and the chassis components were starting to be weighed as we added them:



We hadn't thought much of what was going to go in the front as yet, but around Xmas 2010, we started looking out for kitchen bits and pieces, plus we wanted a fridge and toilet. While these were available commercially, they were fairly expensive if bought new, and we were looking at secondhand caravan components to keep the costs down.

We found an ideal kitchen assembly, but it was in Perth in Scotland! Nonetheless we had to go to Inverness with the trailer for our company, so we called at Perth on the way back and collected it. Later on we were to sell this set and buy something else......

25th November 2010, we ordered the steel, half a ton of box section from Parker Steel, delivered to our metalbashers who are going to weld up the chassis. I hoped to be there as well, getting my hands dirty and perhaps getting to grips with our own 260amp MIG welder, it would be a useful bit of experience for me, and our youngest son, Philip, who was already proving to be very handy with the welder.

Cost with VAT and delivery was £616.08.

75 X 50 X 3mm - 2 lengths Floor cross-beams
120 X 80 X 5mm - 2 lengths Main chassis rails
100 X 100 X 4mm - 1 length Stiffeners, one each end and two at the step in the frame
100 X 50 X 5mm - 1 length Drawbar and axle frame for the front

All the while, the Forum discussion was going on, with loads of input from interested members, so I had plenty of advice and thoughts on the subject!

12/01/11


The front axle centre pivot took some thought. It had to carry the weight of the front of the trailer, while doing the steering as well, plus braking. Traditionally it is usually a ring thrust bearing, bolted or welded to the chassis and axle, but we found the costs to be very high, and so we looked at an alternative. We finished up with a vertical steering pivot, carried in three large bearings bolted to the chassis. Two of the bearings would carry the radial thrust of the pin and a third would carry the vertical or radial thrust. Fortuitously, we found the two large pillow-block bearings on ebay, and the other thrust bearing came from a bearing supplier.



The steering pin was housed in the axle pivot frame in a circular housing, bolted to a heavy box-section housing that carried all of the loads on the axle:




18/01/11

The components of the centre pivot all came together fairly quickly, but we had problems with the heavy rectangular box section that we had bought, it was distorted enough to cause problems with seating of the bearings, so we had to take it to a machine shop to be straightened on a hydraulic press.


Once that was done, we could send the cut pieces away for machining to take the radial thrust bearings, the wall thickness is 10mm:



Once machined, they were a fair bit lighter:







The retaining bolts for the bearings were machined down as they were slightly too long to swing into the holes, as there were two sets on opposite sides of the box section,and the heads took out a fair bit of room. We then welded them into place while clamped up with a bearing as once the housing was welded into place, the bolts would not be accessible:





26/01/11

While this had been going on, we had been getting other parts sorted out. The steel had been delivered to Eastbourne, and we had drawn up and ordered the various gussets and brackets needed for the chassis assembly:

The main 'Z' sections for the step in the main frame:



The Drawbar eye side plates:



The gussets for the main framework:



The brackets for taking the body side struts:



The fittings were all laser-cut from 6mm steel sheet, which mean that we had no finishing to do, all the parts were right size first time.

The front axle framework drawing was now done:



We introduced a cutting schedule on some of the drawings so we could see at a glance what material was going to be used in each assembly. Later on there was an exploded view drawing of the main chassis with each part dimensioned.

Chronologically, we were now in January 2011, and we had nearly everything ready for a building session, just a few odds and sods were needed, plus we were waiting for new wheels and tyres for the front axle. The other new wheels had been shot blasted and Zinc sprayed before being painted, and we had to do the same with the two additional wheels. Then we found that the tyres we had bought for the front axle were winter tyres, so we had to get them taken off and changed.

Materials for the body were being organised, but we didn't want to take delivery and have the sheets of GRP/Ply out in the weather while we waited for the chassis (Although in fact it was the driest and warmest March/April/May we had had for a few years!) so we put off getting the sheets delivered until the chassis was nearly ready for them. What we did do was to find three sheets of GRP/Polyester honeycomb sheet at a knock-down price on the web. It was a discontinued product and we were able to snap up three sheets.

They were in Chester, but again, we were going that way on a service call, to Chester itself as it happened, so collection was arranged:





That fortunate purchase would provide the main floor material throughout the trailer, and the remains would be enough to do the central bulkhead between the two halves of the trailer, against which the kitchen and bathroom would be constructed on the living side. It was pure luck that we found the material when we did, and very handy to be going to Alstom at Chester a week or so later.


The other materials that were arriving included the two long lengths of heavy aluminium chequer plate, bought off ebay and very nicely packed up by the seller. This would go on top of the 21mm GRP/Polyester honeycomb, to give more weight carrying capacity to the floor. Later on we were to have some issues with this aspect of construction when we changed the format of the Ruston trolley/chassis.



One of the issues with the heavy engine on its trailer was the weight-bearing ability of the trailer floor in the back section. The front half wasn't an issue as it was just us in there, but the engine went over a ton and a half, and we finished up with having support channels between the floor beams, so that the engine would sit directly over the beams for travelling and would run over the support channels between the beams when unloading. The drawing below shows how it was designed originally, the engine trolley outline is in green. Note that there are SIX wheels on the trolley as originally built......




28/01/11

The metal blanks for the trailer pivot assembly had come in, so we popped next door to have a look at them and see what we could machine outselves and what the machinists would have to do for us. We could make the top safety cup and the bottom plate out of the assembly, but the main pin. thrust bearing housing and bottom cup would have the be done outside, our little lathe couldn't handle that stuff. We did make up the drawbar pivot pins out of a couple of M30 bolts:








05/02/11

At this point, we bought a caravan. Quite a nice outfit, except that it had had a bang at opposite corners and was uneconomical to repair. We saw the advert in Pre-Loved classifieds, and after checking what was there, we did a deal with the owner and bought it. It was fairly easy to get back home, but we had nowhere to park it while stripping it down, so we asked Chris up at the farm if we could store it inside in one of his buildings while we stripped it.

We didn't take any pictures of it while we were doing the work, but the caravan provided us with a complete cooker hob, oven, fridge, cassette toilet and water heater, all at a fraction of what it would have cost to buy new. Here are some pictures of the equivalent caravan that we took off ebay (with the seller's permission)













The main attraction was that the complete kitchen unit was squared off in all sides, so relatively easy to put into the trailer body. The shower wasn't actually used in the end, we got one from another source, but the Carver Cascade II water heater was a big bonus as it had not long been replaced. What we couldn't use from the Swift we sold on ebay, eventually getting our money back, but not our time obviously.

It was the start of February and we were readying ourselves for the trip to the metalworkers and the main chassis assembly. The rest of the machining had been done, and we had all of the parts back for the main steering pivot, there were the clips and nylon washers for the main drawbar pivot pins and the main drawing showing the interior layout was also done, based roughly around the Swift caravan parts:











06/03/11

February came and went, and after some delays, we loaded one of the vans up with the equipment, welder, overalls etc etc and headed off down to East Sussex at the start of March, where the main chassis material had been delivered at the end of 2010. We stayed with my sister who very kindly put me and Philip up for a few nights, which saved us travelling time and the cost of a hotel.



We had brought our own MIG welder and cylinder along as we didn't want to stop our metalworkers from their own work by tying up their main welder. As mentioned previously, the cutting drawing for all the pieces of the main chassis and the subframes had already been sent down ahead of us, so when we arrived, work was well under way:



Big Dave welding up the front drawbar frame:




Welding the steering pivot bottom half into the front axle support frame:



Drawbar pivot pins and retaining clips/washers:




Main Chassis members with the step welded up and gussets welded over:




Close-Up of the gussets on the outside of the mitred joint in the frame step:



Frame (Upside Down) having the cross-members welded in. Steering pin support over to the right.



Dave takes the frame outside to turn it over:



Frame now right way up, Philip at back getting ready to start welding brackets on the sides:




Chassis with axles fitted, note the areas for strengthening the floor for the engine trolley, in new steel:



Front view of the trailer with drawbar attached:



Closer view of the steering pivot::



Philip working on the frame step stiffening gussets, rest is almost finished:




The finished chassis outside the workshop:



Another view of the finished trailer:



The pictures don't do justice to the quality of the work done by the two Daves in the two days we were there. Although most of the chassis details had been worked out in advance, we had a couple of problems with interferences between parts that hadn't shown on the drawings, but a work-around was sorted very quickly and we carried on. Philip also put in some excellent welding work on the frame brackets and gussets.

They both deserve full credit for the worksmanship they put into the chassis. We took it home on completion, and it towed pretty well, if a little unusual to see the front bobbing up and down in the mirrors with nothing else in view! We had planned to get it into the shot blasters the following day, to be shot blasted and Zinc sprayed, before it went to the painters for powder coating.

Another point which should be mentioned, is that none of the drawings were just one issue, we got up to 8 or 9 revisions on some of them, mainly small details, but by no means were the drawings right first time.

22/03/11

The chassis had taken a fair bit of time to complete and get into the shot blasters, but we still had all of the body to build, and we started to get the detail drawings done that would give us the information we need to order materials from. We had already been in touch with Aalco's technical rep, and he had been talking to us about their range of transport extrusions for body building. He had also suggested a local bodybuilder that could help if we couldn't do it ourselves. Unfortunately this was to prove a bit of a dead end, as the company concerned didn't take us seriously when we showed them our drawings, and never responded to our request for a quotation, so we decided to go it alone and build the body ourselves, outside the house.


Main bodywork drawing with roof beams and side raves and supports:



Another version with the details of the corner posts etc:



While waiting for the shotblasters to do their thing, time was ticking away, and we had to have the trailer ready to use for the Nuenen engine show in May. It was now 23rd March and time to get body materials sorted out. The chassis was taking longer than promised, and we were losing time, but until we had the chassis back from being painted, we couldn't do anything in the way of cutting metal for the body.

What we did do was to get the extrusions and panelling sorted out, so that we could call for delivery with a few days notice, that meant that we could respond quickly once the chassis was ready.

Decoration for the side of the body was being discussed about this time, and I wanted to see about getting a big Ruston decal printed, but a big one that would be about 800mm to 1000mm diameter. There was no master image available, and the examples I had were small transfers that I had bought from Ray Hooley, but after a while I decided that if scanned at a high enough resolution, we could clean them up and make good adhesive labels from them. It was to be more than a year before we actually got them printed and fitted!

24/03/11


This was the chosen image for the transfer:



29/03/11


By the end of March, we had delivery of the extrusion sections for the body. There were 8 different types by memory, and we had to go back twice for more material before we had finished. Aalco were great to deal with, I had excellent service from their Nottingham branch with prompt deliveries by their own trucks:





Quality and handling were good, and we didn't lose any material through handling damage or blemishes. We can recommend their service with no hesitation.

Ratings for the wheels and axles were being discussed at this point in time, and with 3900kg total axle capacity and 4380kg tyre capacity we were well covered for our design weight of 3500kg. In fact, with overrun brakes we couldn't have any more weight if we wanted it, plus the Discovery we towed with had a maximum limit of 3500kg, so it all fitted pretty well.

Finally, on the 13th April we were able to get down to collect the chassis from the shot blasters. It had taken nearly a month instead of the week they promised, which put us at risk of running out of time before the Nuenen show. The shotblasters were located at Waltham Abbey, and it was a fair run down for us, then we had to take it over to Royston to the powder coaters.



To get a thing this size painted is not that easy, and to get it powder coated even more so, as you need an oven big enough to take it all. Fortunately, Conqueror at Royston were fully equipped, and we knew tham from work they did for our company. It was a bit of a slog, building the chassis up with the axles etc at the shot blasters, then pulling it all down again later in the day! They promised to have it done by the 15th and it was done on time. The finish was excellent and we were very pleased. Assembly didn't take too long, we had a few tight bits with paint on, but it took less time than we expected, we were getting quite good at it!

15/04/11


Front Drawbar frame:



Close up of the quality of finish:




Main chassis hanging on the oven trolley:



Hooked up and ready to leave for home:



16/04/11

Getting it all back home was a big relief, we were due to take the Ruston 1ZHR engine to Nuenen on the 10th of June!



We started fitting the outrigger extrusions straightaway, they had all been cut on a CNC saw so were all dead accurate. It didn't take that long, we just G-clamped the channel to the chassis bracket and drilled through, deburred and bolted it all together. We used stainless-steel fasteners all the way through.


16/04/11

Once we had the chassis more or less ready to build up, we got all of the extrusion material down from the factory where it had been delivered, mostly on our shoulders! We live two streets away from the factory so it was just as easy for two of us to walk down with the lighter pieces. Cutting to size was an issue, particularly with the larger width of the side rave extrusions, and we eventually finished up using a steel 1mm cutting disc in a hand grinder to achieve some accuracy and finish. We did buy a circular chop saw, and that was OK for some parts, but the small cutting disc did far more work.

Rita stands at the front of the house while I take a shot of the chassis, just after we started on the body.


The Build

We had to build up an outer framework of side rave extrusions, so that when we came to fit the body sides and front and rear panelling, they would have somewhere to fit onto. The support extrusions were on pretty quickly, less than a day if I remember rightly, but then we got into the corner extrusions and the side rave extrusions, and it wasn't so simple!

20/04/11

The extrusions were stored on the floor by the trailer, wrapped in a green tarpaulin. We had regular visits by 'travellers' and the like, so we had to cover up anything that would be easily disposed of, not so much of a problem in 2012 when I am writing this, but in 2011 it was a big problem. The very long top cant rail extrusions were pushed down by the side of the house, as they were too long to go in front with the other stuff.



24/04/11

The next consideration before we got too far ahead of ourselves, was to fit the winch mounting before the floor was sealed in place. There are no bolts or screws holding the floor, it sits in place on beads of Parabond600 adhesive/sealer, and the top is sealed with Sikaflex 221. The winch was bolted through the floor on spacers, so that all stresses were taken to the chassis and not through the honeycomb.

The winch was a 5000lb pull 12V type from ebay, and it has done the job well.




Once we had the flooring sorted out, we had to strip off the protective film on both sides, which took two of us over an hour. Once it was off, we applied the sealer onto the cross bars and laid the panels in place. We then ran sealer into the joint between the panel and the chassis and left it to cure. Once it had gone off, there was no getting it out again, not without a lot of work.

On top of the flooring in the back, we had arranged for two lengths of heavy chequer-plate to go on top of the honeycomb sheet. This was to protect the surface against stones in the tyres of the engine trolley and general wear and tear.



The compartment where the engine was housed had to have four strong points for lashing the engine and trolley down, so we had previously arranged for four of the corner gussets on the chassis to have 16mm holes in them, and when the floor was fitted, we punched holes for the spacers and then bolted the eyenuts in place from below.

Hole in chequer plate and honeycomb for lashing eye.



One of four Lashing eyes bolted in place on its through-spacer.



In timeline terms, these eyenuts were fitted a week or so later than we are picturing it here, but it fits in better with the narrative this way.

25/04/11

The framework takes shape as the flooring panels are fitted. One side rave extrusion is laid in place.



We played around with some odd offcuts to see how the side rave and corner extrusions would fit together, and how they compared with the theoretical assembly on paper. In fact they agreed pretty well, the biggest problems were dimensional creep and innaccuracy in measuring or cutting material. We would improve, but in the early stages it was all new to us and we didn't really have a lot of input, other than the Aalco rep who was very helpful.

Playing with bits and pieces one evening after dark.



The construction of the body was fairly simple and generally followed truck body practice. The outriggers carried the main body weight in the absence of cross-members, and each outrigger had a stainless steel bracket bolted to it, which then sandwiched the body panel between itself and the external side rave extrusion. All of the brackets were pre-drilled, so all we had to do was to place the body panel in place and drill through from the inside, then bolt it up.

One bracket, bolted in place but no body panel between it and the side rave extrusion..



As we moved round the chassis, we used off-cuts of GRP/Ply to space out the brackets so we could get the holes drilled in the right places. It worked out fine, but we knew that eventually we would have to bring the main sheets down from the factory yard where they had been for a few days.

28/04/11


Two main side sheets of GRP/Ply sat on pallets in the yard, with the smaller front sheet on top, waiting to be cut to size.



The side panels, trimmed to size and with the cut-outs to fit the side rave extrusions on the chassis.



We continued with the side rave framing, and it took about a week to finish off, with one section having to be re-done as I wasn't that pleased with what I had done. Generally it looked pretty good, if a little complex. All of the nuts and bolts and brackets looked a bit Heath-Robinson, but once in place the side panels would smooth them out. The GRP/Ply sheets are £463 plus VAT each for the 23ft X 8ft sheets. £156 plus VAT each for the 8ft X 8ft sheets.

05/05/11

The framing came to a successful conclusion, with the exception of the rear n/side framing for the wheel arch, which I wasn't happy with, so later on I would strip that corner joint down and remake the whole piece. The problem was the angles that we cut with the grinder, they weren't always as accurate as we needed and had to be dressed with a file afterwards to get the joint looking nice.

The chassis with the framing almost completed.



Starting to get the front/top framing and corner pieces organised.




Corner joint at the front n/side. The corner section is only for trial fit, the real piece is nearly 6ft long.



06/05/11

Front panel up in place. First significant panel at last!



Inside view, showing the brackets etc.



From the front.



The corner extrusions in place. They had to be changed later as we had made an error in their length.




This was pretty heady stuff! We were running along pretty well and it all looked good. Nothing had cropped up with the method of construction, and apart from an error in cutting the corner extrusions we had no material problems. On the day in question, the 6th May, we got the two boys and one of their builder friends round at about 5pm and decided to go for a lift on the side panels.

Contrary to popular belief, the sheets are quite flexible and heavy, so easily damaged. It was fairly breezy, but with Rita as well, the five of us tackled the first sheet. It was a struggle until we got it up over the sides, but it dropped in place OK and we were able to pop a couple of self tappers into the end corner extrusions to hold that front corner together.

First side panel in place, almost forgot to take a picture in the excitement of the moment!




Suitably emboldened, we then had a go at the second side. This one wasn't so easy as it was up against the neighbour's fence, but we got it into place without too much trouble and I popped more screws in to hold it up in place. At this point, the rear edges were flapping around a bit in the breeze, and we had to clamp a piece of material across the open ends at the back of the trailer to stop it going too far and damaging something.

Second side panel in place, bit more awkward but went in OK in the end.




All this time we had been building the trailer, we had had a number of passers-by stop and ask about it, and it was becoming a morning conversation-piece for the kids and their parents on the way to school. I also had a few 'regulars' who would stop and have a chat while it was being built.

Shot of the interior, just after we had lifted the sides on.




Second shot of the interior.




We called it night then, it was the best we had done in any single day, and a big step forward towards the finished item. Clearing away tools and materials and sweeping up metal swarf always took 30 minutes or so each night. We have cats, and the swarf was dangerous to them if it got into their feet. We had found the fault in the length of the front corner extrusions by now, so we had to order another length from Aalco on Monday (today was Friday) but we had a lot to get built now the sides were on.

08/05/11

The next job was to fit the top cant rails at each side and front/back, so that the roof bearers could be fitted. Once that was done, we could fit the roof sheet. In practice, this was a big job, as the cant rails needed to be stuck in place with the corner castings as well, so it was a once-only job, we wouldn't get a second chance at it. In practice it went OK, the extrusion slots had to be primed with adhesive and then lifted up into place over the side panels, after which the corner casting caps could be fitted. It sounds fairly easy, but we had a couple of trial assemblies to make sure we had it right.

Picture of the roof bars going up into position. The roof vent was one of a pair that were designed to go on the roof, but in the end we didn't use them.



Next were the roof support extrusion. We used a standard 'Top-Hat' extrusion which we cut to length to suit our own body. Each one is then fixed at each end with two bolts. A truck body builder would use large rivets, applied with a compressed air tool, but we didn't have the facility and pop rivets were too small for the strains involved. Although fairly 'bendy' when in place, they would support my weight if I spread it over a few beams with a plank or board.

Shot of the roof, almost finished.



We did fit four beams with one flange missing on one side, this was to give us the aperture for the roof vents. In practice we didn't go that route and found that the top opening window vents were more than adequate. Next job was to finish off the rear aperture as the body was not very strong in torsion with the end being completely open. The rear corner posts interfaced with other parts as well, so we had to get the whole area ready before we glued them into place. We did have to cut down the side panels by 8mm in length after we found that we had miscalculated the depth of the channels in the corner posts. That was done with the trusty angle grinder and cutting disc.


10/05/11

Rear door opening after we got the corner posts up.



The panels each side of the rear door and above it would have to be put into place now, and we got them cut and trimmed ready to put into place. We also made up stiffener panels to go across the joints in the panels to spread the load when the body twisted. The corners were dealt with by an aluminium casting that was used for all the four corners. Simple to fit and secure, they weren't cheap but a good solution.

11/05/11

Interior view of the bottom corner post fitting.



Getting the rear panel in place, it consisted of 3 pieces with horizontal joints that we covered with a stiffener panel. We used offcuts wherever possible.



Interior view of the top corner casting and corner post fitting.



We had been having warm and dry weather up until now, but then we got hit by a couple of heavy showers. The next picture shows the PVC/Nylon sheet over the roof beams to keep me dry! The rear panel is finished apart from the opening trim and the stiffener panels.



Looking along the floor and out of the back. Floor is waiting for the wheelboxes to be made.



Interior view of the stiffener panels over the joint in the rear panel. Panels are 14swg NS4 Dural.



The roofing sheet had arrived, a big coil of opaque glassfibre which was supplied in a standard width, but cut to your required length. This was stuck down the the cant rail tops and the top faces of the roof beams with heavy-duty doubled sided foam tape. Then it was held on all four sides by an aluminium moulding on top, riveted down with sealed pop rivets at 200mm centres. We used Sikaflex 221 between the moulding and the roof.

15/05/11

Marking out the roof material was a bit of a laugh, as it just wanted to roll back up like a swiss roll if you let go of it for a minute, so we ended up with it in the road outside the house, held down with house bricks! We live in a cul-de-sac which is pretty quiet during the daytime, so nobody was inconvenienced. The angle grinder with cutting disc did the job quickly and cleanly, and really earned its keep on this job.

The aluminium moulding that was going onto the top of the sheet had to be drilled through and so did the cant rails, so that was the next job. The capping ran along both sides and across the front and back, with 5mm holes at 200mm intervals. Then we had to go back and de-burr them all....


Roof bearers and cant rails with double-sided tape applied.




Once we had it all ready, we got the roll up onto the roof and laid it out, fixing it down with weights until we could locate it accurately on the roof. Starting from the back we rolled the roof towards the front, peeling off the protective layer on the double-sided tape as we went. It lay down fairly well, but we had little gullies in between the bearers afterwards, so maybe we should have unrolled it the other way instead.


Roof sheet laid in top of the bearers, but the protective layer on the double-sided tape hasn't been removed yet.



Roof sheet stuck down onto the adhesive tape and bolted down front and back. Capping moulding to go on yet.



Looking up from inside, the roof is fixed down finally and sealed. Hasn't leaked at all yet. The framing for the central bulkhead is in place, with an offcut sitting inside it.



Close up of the rear o/f top corner inside.



Once we had the roof on and sealed up, we could get on with the interior. What we had so far was an empty shell with no back door so we couldn't leave anything inside of value in case of theft. The floor above the front axle was trimmed and fitted and sealed. Once that job was completed we could concentrate on getting The internal divider erected and the side door cut out and made up.

We had already bought a caravan door and frame, plus we had one from the Swift caravan that we had broken up. The problem with them was that caravan walls are much thicker, 30mm to our 14mm, so the doors we had wouldn't fit without a lot of modification. That wasn't a big problem, just something else to manufacture.

17/05/11

Last of the big offcuts of 21mm honeycomb. We used this material for the floor and dividing bulkhead. Rita in the living section.



Another job at this time was to get some lighting into the body so we could work on in the evenings. Four circular 12V flourescent lights had been purchased and now we got them up on the roof supports and temporarily wired in for use. Each one has its own switch so we just fed 12V on a ring main to them. Their location was revised after the first year, but the basics are the same, two in the back and two in the front, to which we added two spotlights in the front living section, with a pair of linear flourescents over the sink/cooker area.

20/05/11

Interior lighting as originally fitted..



At the front end, we had laid out the Swift caravan beds and cupboard to see how it would fit into the area we had designed for it. With just a few packing strips it went in without any modifications, the only issues we have had are that one frame for one bed had to be repaired after a piece was taken out by a previous owner to clear a battery box that he fitted. We needed six strips of hardwood, two for the bed frames and four for the seat cushion back. Our local timber place cut that for us, and after we fitted it all in, we had some offcuts which came in at just the right sizes for some other jobs later on.

First layout of the beds etc in the front. Cut-outs in the bed ends are still there, got to make new ends up.



Layout now with packing strips and beds screwed down firmly. Centre fill slats were a bit of a problem early on, but we solved that later.



At the back, work was still carrying on, but I had to work at both ends now, so it tended to be one end in the morning, then the other end in the afternoon/evening. We were working on the wheel boxes/mudguards at the back, as they were something we couldn't travel without. In the end, they worked out well, we bolted a large piece of honeycomb to the chassis to form the inner side, then boxed in the rest and used aluminium angle to finish it off. It looks OK and is very strong, you can walk on it or jump up and down on it.

22/05/11

Wheel box on the o/side, looked tidy and was fairly economical. We used up most of the odd offcuts of the 21mm honeycomb.



Wheel box on the o/side, close-up of the mitres.



Wheel box on the o/side, another view looking towards the back door.



It was now 22nd of May, we were approaching the trip deadline fairly quickly, with lots of major jobs still to be done. We reckoned that we could live without the kitchen and bathroom for the first trip, as it was going to be to Nuenen, which had showers and toilets for the exhibitors, and we could rustle up loads of cooking gear. Our son, Philip was coming with his Land Rover, and then going on down to France afterwards, so we had his cooking gear as well.


23/05/11

We had not forgotten the external side of the trailer while we were inside, but we needed fine days to be up a ladder working 8ft off the ground. Despite a few breezy days we got the rain gutters up in place and also fitted the side, front and rear marker lights. Mainly just a case of cutting a hole for the light body and then sealing it with Sikaflex 221 before screwing it to the body. The lights contain four LED's and aren't too bright but are OK in darkness. Reflectors were also fitted at about this time.

Rear marker lights



Side marker light with rain gutter above.



Lower body reflectors.




All lit up on battery power. Interior lights quite good at night.



Next on the jobs list was to sort out the door into the front living section. This would then fix the positions of other things like the windows and the kitchen units. As we said earlier, the two caravan doors and frames that we had weren't any use as they were for a thicker wall, so in the end we cut the aperture and used the material that came out for the door. We had already ordered aluminium channel and framing extrusion, so we got that done fairly quickly with the jigsaw.

25/05/11

Side door cut out and framed, no rain gutter or hinges/lock yet.



We were now at the 25th May, still hadn't sorted out the brake linkages, finished the beds or the cooker etc etc. The list of jobs seemed to be getting bigger not smaller! The extrusions for the rear ramp/door had arrived and we had them cut by our machine shop next door, their CNC saw was magic for accurate repetitive sawing, just what we needed for the expensive bits of extrusion. We had two pieces of large channel extrusion that we were going to use as ramps, but the addition of the floor plate extrusion gave us a full-width door as well as a walk-in ramp.

27/05/11

Rear door/ramp support extrusions in place.



Rear door/ramp assembly of floor extrusions. We had just enough room to lay the ramp flat, it was a bit of a squeeze!



Rear door/ramp on its side to show the construction.



Framing trim round the edges of the floor planks.



28/05/11

Rear door/ramp support extrusions after chamfering.



The chamfering of the big channel extrusions took a while, but again we used the little angle grinder with a 1mm cutting disc. It didn't much care for aluminium, but did the job well and all we had to do was to clean up the cut with a file to take the burrs off. The completed door/ramp was too big for me to lift by myself, but I could manhandle it around. The pivots had to be drawn out so that we didn't finish up with a situation where the door couldn't open down because it was fouling part of the body.

29/05/11

Rear door/ramp pivot blocks. M10 bolts go into threaded insert in the main chassis. Nylon bushes all round.



Rear door/ramp pivots and (temporary) steel pivot bar. The bar was replaced by a piece of Dural to save weight.




Rear door/ramp pivot assembly, unpainted. A stainless steel spacer was fitted later to keep the nylon bushes in place in the channel.



Rear door/ramp complete.



Rear door/ramp complete.



The back panel of the trailer was fitted with 3/4" foam strips that the rear ramp closed against, to make a fairly good weather seal. We fitted two spring loaded side bolts to keep it in place while travelling, and there are two wire rope safety strops that hook onto rings on the ramp, so if the bolts failed it would still be kept from falling down. In 2012 we fitted hasp and flap padlockable fittings and now the back and side doors are kept padlocked.

30/05/11

Because of the weight of the ramp, we thought about a small cheap winch, housed inside the top of the rear body so that we could raise and lower it like a drawbridge, but to date we have managed without it. It's on the cards to be fitted at some time, but we have various safeguards to sort out, just in case the battery goes dead and we cannot use the winch to release the ramp and lower it.

Power for the winch(s) and the lighting etc was to come from a 12V 110AH battery set. These were put down by the central bulkhead, in front of the wheelbox. All of the electrical stuff went up on the bulkhead on the offside of the trailer. We fitted a standard Wylex RCD distribution with 3 MCB's and 2 spare positions, a 24-way low-voltage fuse/distribution board and a 26A power supply that we used for a charger/shore supply.

Pair of sealed 12V 55AH batteries for the trailer power.



Batteries and winch wiring.



Electrical system as first built. 240V distribution box, low voltage fusebox and 26A charger.



Side door hinges and lock had been a problem, the lock was the wrong hand, which was our fault and a replacement ordered. The hinges had one out of the three with the arms assembled back to front, and as they were angled out from the mounting face, we couldn't use that hinge. The suppliers got us a replacement fairly quickly, but it was 2nd June now and just over a week before the Nuenen trip.

Next job was the mudguards for the front axle. Although it is covered by the body at all times, the axle still generates a lot of spray, so individual mudguards were bought some months ago for the job. Looking through the metal rack I found a piece of 30mm X 6mm flat bar, horribly dirty and greasy but brand new under the gunge. 4 bits were cut on the Rapidor, then a quick trip to the factory for a session on the bender, which meant that we had four identical brackets rather than four bits of bent steel that looked similar! Brought them back and after a session with blocks and G-clamps, worked out holes etc., drilled them and fitted to the mudguards. It was gone 9pm when I finished that and too late to start drilling holes in the chassis.

01/06/11

Front mudguards with brackets fitted.



Another view of the mudguards.




Mudguards in place on the trailer front axle.




Had to take them off again to paint the brackets!



Meantimes, the rear door/ramp was up in place and finished, and looked fine. We still had to fit the sealing foam round where it closed up to on the rear panel, but it looked good and it all worked well. The safety cables were about to be put in place as well, so we couldn't accidentally release the ramp and have it fall down and hurt someone behind. From inside it looked pretty good too.

Interior view of the rear door/ramp.



06/06/11

6th June, the windows that we had ordered turned up. That was just about the right time for me, as I had a wait for brake cables. It took half a day to mark out and cut the apertures, the fit the windows in place with Sikaflex221. The weight of the windows wasn't helped by the fact that we had laminated glass in the frames, but we preferred that to makrolon or toughened glass.

The windows had top vents that opened inwards, so were fairly weather proof. The design was one used on canal narrow boats, they were made by Caldwells Windows in Wigan, and their service was excellent. We asked for obscure glass in the bathroom window, but other than that they were standard units.

Off-side view of the windows, bathroom has obscure glass.



Near-side view of the windows.



Bathroom window and obscure glass.



Interior was much brighter now.



Things coming together fairly quickly now, the mains inlet socket was fitted and the cabling tidied up in mini-trunking, the seats and cushions that had been away to have the backs renewed were due back the next day. The drawbar A-frame had been away to rectify a distortion that stopped it being fitted easily, that was back now and we were able to fit a triangular frame with towball so the drawbar could be swung up out of the way and locked in place,

Tidied-up electrics. Mini-trunking is self-adhesive, very useful.


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