Thread: Plan B trailer build

after the failure of plan A

http://www.woodworkforums.com/f184/t...1/#post1051583

I am pretty much starting from scratch now. (can't even use the old springs or axles)

Aim is for a trailer that will hold an 8' plastic dinghy, and associated stuff.
and allow for a camper build to go over top later on.

So far I've decided, main rails and A frame will be 75 x 50 x 4 RHS.
Cross rails will be 75x 40 PFC.

Internal dimension need to be 1210 x 2500, was thinking of just using a sheet of ply for the floor (1220 x 2440). Can anyone help with what spacing the supports would need to be at to use ply, and what thickness ply?

thanks
Frank

Hi Frank,
I would suggest one cross the middle and one either side of that which will give you about 600mm spacing. I put 3/4 ply in my 7x4 trailer, it was seconed hand concrete form board. Maybe you could look around and ask a concreter to buy a piece, new supermarkets are the place to go.I have built a few trailers over the years and the sides usualy help keep the chassis ridged. I notice you are using 75x50x4 so you will be able to keep the sides light as it will already have a strong base.
When I build a trailer my aim is to make it as light and strong as possible for the job it's intended for. Some of the high tensile RHS they have out means you can keep the sizes down and still be as strong.
Dave

I go along with Dave J on this and use 3/4 formply.

Source mine from the big B (price and convenience)

As far as new 3/4 formply goes the Big B normally carries 2 grades. The structural stuff is over $100 a sheet. I normally just use the non structural stuff at around $64. So far havent sourced it for cheaper.

They seem to chop and change the cheaper stuff they buy in. Recon the brown colored stuff isnt as good as black. Personally think it doesnt cut or handle the weather as well.

Think u made the right choice and scrapped plan A.

I examined the span and load deflection tables for plywood, and decided that 12mm with 480 span would suit my use of the trailer. I've ended up with 450 spacing, and I have recessed the ply 15mm (so that in future if I think I need thicker I can go to 17mm with just a small chamfer).
purchased axle, springs, brakes, hubs, and a sheet of 12mm structural CD ply. bought australian ply. apparently all australian ply is metric (1200x2400) whereas the imported is imperial (1220x2440).
so cut my PFC and RHS today, laid it out, levelled it, measure, adjust, repeat 5 times until square.

tack weld, check square.
then out with the angle grinder again to cut the front RHS off.
forgot to cut the holes to allow galvanising to flow
reweld

hopefully do the spring hanger mounts tomorrow (going to make up brackets to spread the load) and the A frame as well.

Got all the spring hangers made up (must buy a plasma cutter one day) and tacked on.
Realised my RHS is not as long as I thought it was. Will have to buy some more before I start on the A Frame.

The A frame pivots are now tacked on, and A Frame bent, can't weld it until I buy a hitch. Thinking of getting one of those hyland ones, not cheap though.
The regulations are a real pain with their hitch height restriction. I wanted to make the trailer sit at the same height as the landcruiser, but I have to put the hitch lower.
Plan on putting it down between the A frame members, this should just get it low enough to pass.

I think I've worked out how to comply with the stupid ADR restriction on ball coupling height (must be between 350 and 420mm from ground to centre of ball with a laden trailer).
If I put two hitch mounting plates (top and bottom) on the A Frame members with the hitch bolt pattern in both plates then mounting the hitch on the top plate will keep the trailer at the right height for the cruiser, and by having the bottom plate (where I can mount the hitch on the underside of it). I can demonstrate the "provision to adjust coupling height to within the regulation range".

Must put a costing up at some stage, trailer parts place is making a fortune out of me.

Hitch attachment done, 12mm plate top and bottom of the drawbar RHS. With hitch mounting holes in both plates.
Done one side pin to hold the drawbar frame.
Getting close to turning it up the right way. Althought should probably do the brakes, and wiring routing whilst it is upside down.

Handbrake mount done,

trailer right way up now
and one side on.

was aiming for using it over Christmas, but is not looking likely.

Looking good so far.

I see the axle with brakes on it, what size / what bearings did you get?

With that chassis, and those spring hangers, you either plan on doing the Oodnadatta Track, or carrying the QE2.

I try to help guys from making costly mistakes, that's why I asked for this trailer section to be started, but it looks like you're doing fine. Keep it up, and keep the pictures coming. Everybody loves pictures!!


Y.

Hi Yonnee,
must revisit your thread to see how your trailer going.

I'm aiming for 1250kg Agg, so have 45mm axle, slimline bearings.

Yeah, its a bit heavy duty, hoping to come in under 500kg Tare, must update my weight spreadsheet and see how I'm doing so far. A lot of the trailer is determined by what steel I have lying around, the spring hangers being one of them. The overall heavy dutiness is determined by me being fed up with trailers that bend.

I reckon its all these forums faults for even starting on this costly build, too many great people out there encouraging others to achieve dreams. Keep it up.
cheers
Frank

Originally Posted by Franklin

Hi Yonnee,
must revisit your thread to see how your trailer going.

**shudder** Don't even go there. Mine's at a standstill till I get this customers one finished.

Originally Posted by Franklin

I'm aiming for 1250kg Agg, so have 45mm axle, slimline bearings.

Bit of advice here. You have the capacity in the axle, so mark your VIN tag at 1450Kg ATM. It doesn't cost you any more to register, will benefit you come re-sale time, and should the unthinkable ever happen, you're covered insurance wise for a bit more carrying capacity.

Originally Posted by Franklin

Yeah, its a bit heavy duty, hoping to come in under 500kg Tare, must update my weight spreadsheet and see how I'm doing so far. A lot of the trailer is determined by what steel I have lying around...

You've been in my shed!! More than half of what I do is from stuff laying around that I've been collecting over the years.

Originally Posted by Franklin

I reckon its all these forums faults for even starting on this costly build, too many great people out there encouraging others to achieve dreams. Keep it up.
cheers
Frank

Thanks Frank.

Y.

Originally Posted by Yonnee

Bit of advice here. You have the capacity in the axle, so mark your VIN tag at 1450Kg ATM.

however my springs are rated at 1140kg (9 leaf, 45mm), I'm assuming that limits me to 1250 kg ATM (assuming 10% on towball). is this the case?

Originally Posted by Franklin

however my springs are rated at 1140kg (9 leaf, 45mm), I'm assuming that limits me to 1250 kg ATM (assuming 10% on towball). is this the case?

How thick are the leaves in the spring? I'm assuming they're only 6.5mm imported springs if that's the rating you've been told they're rated at. I'll check my books at home tonight to double check for you.

If that's the case, then technically you're correct with that weight, however, the VIN tag only states the ATM and the axle capacity, and you can always change the springs to 8mm thick leaves at a later date if you find yourself carrying closer to that weight.

Trust me. It'll be a lot easier to register the trailer the first time @ 1450Kg ATM, even with your current springs, than to try and up it later on. But horses for courses. If you're happy with 1250Kg, then that's cool too.

thanks for that, I may just do that then.