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daddymatty82

could this be possible to be made?

http://www.dragondriving.co.uk/printadvert.php

i want something like this for my pony when she starts to drive i want a four wheeler mainly so i can store it easier as it wont need propping up and just need a tarp over it but a four wheeler will be used to carry hay aswell so kind of put a round bale on the back and bring it home. also will be able to pick my girl up from school and she can sit on a small bale of hay or something but what would it take to make one of these? has anyone you know done it? how? was it costly? i got the time but im just wondering if i could make one but what wood would make it lightweight but strong what thinckness materials? i got someone to weld so all the metal work like the frame i could get him to weld for free. main aim though is to make it light and strong any advice?
Gareth

The link is not working ... any chance of you replacing it please


I will be building a prototype modular construction, lightweight exercise cart on motorcycle wheels early next year ... ... ... just to test the market and see what the response is.

I have already selected 3mm wall thickness steel tubing as the main material. If I get the engineering calculations and the design right, the frame strength will be more than adequate.
daddymatty82

http://www.travellerhomes.co.uk/?p=736  

am trying a differant pic all it is needed is to be a 4 wheeled trolly be able to take the weight of a big heston or a round bale of hay (1 at a time of course)  i want it to be able to  make use of it to transport item about the field and be able to take her in and out the shafts with ease  without the thing toppling over etc. also be able to take kids on the back like at school fetes sort of thing
mogs

i was going to suggest you visit a few gypsy/horse fairs. there are usually some nice carts and wagons for sale at them.
daddymatty82

its trying to find them tbh i know only of 2 and appleby and  stow is the only ones i know of appleby is out of reach atm and stow i always seam to miss few yrs back a cart simular to what i want 500 ish you can get them from around places go to stow and it went for 4k 1 family out bid the other then burnt it  towed it up the road with a bonfire on the back
Hawkeye

bodger used to have one of those, dont know if he still has it . needed quite a bit of work on it if i remember
Gareth

If you are going to give kids a ride on it, and especially at fetes, etc. my advice to you would be to buy one that has been designed and made for that purpose, otherwise the insurance companies, and bureaucrats will go to town on you.

If an accident occurs within 12 months of the cart being made, the maker could be liable as well ... ... ... that is why businesses such as mine have product liability insurance, along with public liability insurance.

Definition: Insurance against prosecution in the event of the misperformance and subsequent damages caused by the use of a product.

Protects manufacturers' and distributors' exposure to liability for bodily injury or property damage caused by the negligent manufacturing of the product. Also referred to in relation to claims arising out of completed work.
Woodsmoke

Gareth wrote:
I have already selected 3mm wall thickness steel tubing as the main material. If I get the engineering calculations and the design right, the frame strength will be more than adequate.


What calcs are you using, out of interest?
Gareth

Nothing spectacular or too taxing; frame structure calcs of possible stress raiser points and any propagation in the design at an estimated maximum shock loading of 3G, along with a running total of design mass, and wheel rim loadings.
Woodsmoke

Gareth wrote:
Nothing spectacular or too taxing; frame structure calcs of possible stress raiser points and any propagation in the design at an estimated maximum shock loading of 3G, along with a running total of design mass, and wheel rim loadings.


I wouldn't be too concerned about the wheel loadings at the moment? As long as you can reconcile the overall rating of the M/C wheels with the sprung mass you should be well within limits. I'd be more concerned with ensuring the yield stress of the material you intend to use gives you a reasonable saftey factor, & that any welds don't affect the local area. 3mm mild steel should be fine, but I'd be more inclined to go for a carbon steel such as 275 as you might find some unexpected bending moments? If you want to be more exotic, you could even go for a stainless such as 316, but for a prototype you shouldn't need to bother. If you do decide to stick with mild, I'd go for certs to 3.2 to ensure you get that wee bit extra strength. The calcs will verify any material at a higher yield stress, and if you move from 275 then you can revert back to 3.1. Any stress risers themselves shouldn't worry you as long as they fall within the yield figure of the material, and within your UTS safety factor.

Are you doing hand calcs, or do you have access to an FEA package for your shock loadings?
Gareth

I wish that I could afford an FEA package; I'd love to see a hot spot wire net diagram of my frames, so for the timing being my trusty Casio scientific, and pencil are receiving a damn good work out.

For the moment I am prototyping in 1 & 1/4" X 11 swg EWR round tubing: because I have it in stock for general purposes fabrications, and for prototyping bicycle frames before moving on to 531 and 4310 at the  manufacturing stages.

Chances are that I'll probably leave 316 stainless steel well alone due to it's expense and work hardening characteristics.
Woodsmoke

If you want to send me your calcs, I'll review them for you (FOC of course)? You'll need to get a certifying body involved anyway if you go into production, so it might save a bit of time & expense?

If all you're going to be doing is welding, I wouldn't worry too much about ss work-hardening? I only suggested it from the corrosion perspective anyway, and for prototyping carbon would do fine as long as you get good pen' on your welds, & don't have any dramatic bending moments in the structure. 4310 is a stainless, and its pretty nasty to weld due to the high nickel content. It's obsolete now though anyway, as is its ASTM equivalent. I'd have a word with your supplier & see if you can get a better deal from him? I haven't even seen it referenced for a good while.

Your 531 is obsolete now too. Its only available as a special, as far as I know. Again, I'd have a word with your supplier & get something to BS4t (anything from 45 to 100?) You'll probably find your costs & lead-times significantly reduce as a result (unless you have it stockpiled?) It'll be easier to use too, as its a cr-mg rather than a moly, & you can use a low-dep' weld such as TIG
Gareth

Yes, currently I have a large stock of 4130 and 531 from a bankruptcy sale about 3 months ago ...... that's why I had to build the steel racking to get the tubing up off the floor and keep the HSE off my back it has paid dividends since because everything is so tidy and manageable now.

At the end of the day that I got the racking into position, it's a different story now though as the racks are almost completely full of material stock:


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