Aluminum Trailer - Need help

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kurz
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Re: Aluminum Trailer - Need help

Post by kurz » Wed Jun 12, 2019 4:14 pm

Neo dit you think about buing just any USA trailer? Mostly they look same with the I beams.

The cut it and make it to an MacGregor Trailer with the mesurements.

Advantage: You have allready the bent I-Beams... Just an idea....

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Neo
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Re: Aluminum Trailer - Need help

Post by Neo » Wed Jun 12, 2019 4:47 pm

Well that's a nice idea kurz but they are EXTREMELY RARE in Australia. And just like the Steel Trailer they are non-compliant to Australian road regulations because they are only rated for 2,000Kgs. So add an outboard and a second axle and it always goes above 2,000Kg and that make me liable for prosecution after an accident.
The cost of a trailer here that is capable of over 2,000Kgs is ridiculous (30% of what I paid for my Mac). So building my own trailer becomes a necessity for many reasons kurz. :wink:

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Jimmyt
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Re: Aluminum Trailer - Need help

Post by Jimmyt » Wed Jun 12, 2019 5:13 pm

I'm in the middle of a bunch of projects, one of which is a desk for my youngest daughter - just graduated and soon to be teaching fifth graders. Anyhow, I'm 2 coats of varnish in, and as I'm applying the 3rd coat, my buddy walks in to talk truck transmission issues. Not sure what happened, but I dropped the freakin' varnish can right on the desk surface. Made a nice dent in the desk, and varnish exploded out of the can. Probably distributed a bit over a pint before I could grab the can and right it. My portable compressor, floor jack, and shop crane caught most of the projectile distribution. The rest went onto the desk and ran off in various directions. Got a splatter about the size of a 1/2" ratchet on a good pair of jeans and somehow managed to dip my shirtsleeve in it too. Made me even grumpier than usual. :x All good now, after lots of cleanup and sanding, etc. but felt like "one step forward and two steps back" at the time. Managed to come up with several new phrases - none of which are anatomically feasible...

I wouldn't be too discouraged about the extra web size. You may be able to make it up with the suspension if you use a torsion axle. The axle bunk and rear bunk will need to be blocked up in the center, but this shouldn't be a big deal. Keep the bunk angles and dimensions right with respect to the top of the I beams and you should be golden.

Regarding beam bending, angles should be the same as far as bending the I beams - Maybe I'm missing your point?

One thing I'm curious about is, if the local authorities are so finicky about ratings, etc, how do they react to a DIY trailer? Are you going to be able to get it registered, or will you have to move to Alabama to use it? :D

We're rooting for you!

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Neo
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Re: Aluminum Trailer - Need help

Post by Neo » Wed Jun 12, 2019 6:09 pm

Jimmyt wrote:
Wed Jun 12, 2019 5:13 pm
Probably distributed a bit over a pint before I could grab the can and right it. My portable compressor, floor jack, and shop crane caught most of the projectile distribution. The rest went onto the desk and ran off in various directions. Got a splatter about the size of a 1/2" ratchet on a good pair of jeans and somehow managed to dip my shirtsleeve in it too.
Take it from me ... Never wear a good pair of jeans and these things never happen :D
Jimmyt wrote:
Wed Jun 12, 2019 5:13 pm
Regarding beam bending, angles should be the same as far as bending the I beams - Maybe I'm missing your point?
Analogy ... Take two parallel lines 2" wide and put 10" between them. Then keeping the lines in place increase the thickness/width of those lines to 4" and the gap between becomes only 8"... On the same bending points less distance between the flanges should equate to lower bend angle.

Jimmyt wrote:
Wed Jun 12, 2019 5:13 pm
One thing I'm curious about is, if the local authorities are so finicky about ratings, etc, how do they react to a DIY trailer? Are you going to be able to get it registered, or will you have to move to Alabama to use it? :D
Due to budget restrictions it's a 4 phase plan over the next 11 months ...
1st Replace A-Frame (u-bolt to existing suspension frame)
2nd Change suspension for Torsion bar suspension (this may never happen)
3rd Upgrade brakes for Electric/Hydraulic 4 wheel disks (has to happen)
4th Update Registration for higher load rating (has to happen)

It's actually all BS!... In my state (New South Wales) I need an engineer to certify the new load rating which costs me $850!!
But if I register the trailer in another State as a home built trailer all I need is a simple roadworthy inspection. Then drive it
home and another simple roadworthy inspection will make me legal in NSW.
Along the way I can use uncertified metal, fit uncertified brakes, suspension wheels and tyres and use a toilet pull chain to chain it to the car so long as the shackle is certified!! :( ... Maybe moving to Alabama is a good idea :D

All the best.
Neo

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Neo
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Re: Aluminum Trailer - Need help

Post by Neo » Thu Jun 13, 2019 2:14 am

Ok guys ... here's another update...
I've found another potential I-Beam. I spoke to Ullrich and they only produce one just I-Beam with this spec...
# 6106 T6 ... Not a typing error!
# Web 117.9mm/6mm - Flange 80mm/8mm ... so there's more meat but it's actually a smaller size beam. https://www.makeitfrom.com/compare/6061 ... n-Aluminum

These dimensions would make it easier to keep with the original design but the big question is "Will it do the job?" ... Or is it a good bet? ... Need your expertise here. 8)

So now I know there's 6106 T6 ... But it has almost identical properties to 6061 T6 ... so why bother? :|
https://drive.google.com/file/d/1t-VhEE ... sp=sharing

All the best.
Neo

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Tomfoolery
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Re: Aluminum Trailer - Need help

Post by Tomfoolery » Thu Jun 13, 2019 7:35 am

That beam is weaker in the weak direction in bending by about 18%, and weaker in the strong direction by about 15%. And the material is a little weaker, too, which makes it worse. But it weighs almost the same (per unit length).

It may be fine. Or not. I don't know what the various loads on those beams are, and what the design factors are, and the connections, and the cyclic stresses (for fatigue analysis), and so on, so I have no comment on the suitability of that section for the application.

Have you tried asking local trailer builders for raw material?

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Neo
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Re: Aluminum Trailer - Need help

Post by Neo » Thu Jun 13, 2019 2:39 pm

Thank you Tom .... Knowing the way that Macgregor built his trailers (nothing over engineered) there's no way I'm going to use a weaker section especially as I may need the trailer inspected by an engineer later. :|

Most local trailer builders here do nothing more than final assembly and the metal fabricators behind them will be buying from Capral, Ullrich or an Importer from China .... The latter will not have credible specifications (if at all) so anyone's guess on strength.
Ok so in terms of material supply I'm going to ponder on this for the next few weeks...Where there's a will there's a way! 8)

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Jimmyt
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Re: Aluminum Trailer - Need help

Post by Jimmyt » Thu Jun 13, 2019 6:20 pm

Image

Image

Here are the remaining numbers.

Remember that the critical dimensions in my pitiful sketch must be maintained to achieve the factory tongue weight/balance. The length of the drawbar must be adjusted to account for the hitch/brake assembly you use. My brake assembly is over 21" long, and only overlaps the drawbar by about 4". If you just put a hitch coupler on the drawbar length you asked me to measure, you won't get the right result, not to mention possible clearance issues.

The V block height and position determines where the boat sits on the trailer (if you bump :) ). So be careful if you modify the v block mount. I measured to the lowest edge in the crotch of the V.

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Jimmyt
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Re: Aluminum Trailer - Need help

Post by Jimmyt » Thu Jun 13, 2019 6:36 pm

And as far as me giving Tom a dig, that would be like Forrest Gump giving a dig at Einstein. :D

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Re: Aluminum Trailer - Need help

Post by 1st Sail » Thu Jun 13, 2019 10:27 pm

what about doing the design in google sketchup? the older version is open source. I used it to design all the cabinets for my kitchen remodel. full 3d, learning curve is tolerable, excellent on line tutorials. I'm planning on building a new double axle for my 26M if I can't find one for a reasonable price US. My daughter is a structural engineer so I plan to tap her for specs.

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Neo
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Re: Aluminum Trailer - Need help

Post by Neo » Thu Jun 13, 2019 10:40 pm

Thanks yet again Jimmy .... I appreciate what you are saying about the hitch but they are very different here. My main objective is to get the Mac in the correct position over the axles so that's way I'm using the plum lined/V-Block point.

Thanks for the tip on Sketchup 1st Sail ... maybe on the next diagram because I've already put quite a few hour doing this on Google Slides.
Such a shame you're not local to me... I need a few I-Beam buying partners becasue Caparal Australia won't make the I-Beam I need unless I buy 12 of them :( .... The Macgregor Alu Trailer had some issues (easily to rectify) but it's by far the easiest trailer to build. Now if I could just find other 6 Mac owners that need a new trailer :D

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Re: Aluminum Trailer - Need help

Post by Jimmyt » Fri Jun 14, 2019 7:10 am

Glad to assist. Let me know if you need anything else. Hope you can work it out.

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Tomfoolery
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Re: Aluminum Trailer - Need help

Post by Tomfoolery » Fri Jun 14, 2019 9:43 am

Jimmyt wrote:
Thu Jun 13, 2019 6:36 pm
And as far as me giving Tom a dig, that would be like Forrest Gump giving a dig at Einstein. :D
More like Forrest Gump showing his war injury* to President Johnson. In public. Was it mooning, or just being very honest? :|

:D :D :D

*On his keister, for those not familiar with the movie.

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Jimmyt
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Re: Aluminum Trailer - Need help

Post by Jimmyt » Sun Jun 16, 2019 7:03 am

I do have limits Tom, and public mooning is just over the line. It scares the children and nauseates the women. :(

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