Critique my trailer plans

[boulderv7]

I am basing my design off of Tony's trailer plans in his book, except we are only going 9' long instead of 10'. So I did center the axle at 40" from the rear instead of 44' like he did. I am also planning on having body mount tabs for the body and tongue box. Our teardrop will be 48" tall, Benroy style.

I am going to have the frame .5" narrower and 1'' shorter than the body to allow for some overhang and wiggle room with mounting.
Planning on a #9 Dexter Torsion axle downrated to 1600lbs, start angle 22.5" down, with 5 on 4-1/2" studs bolt pattern, with electric brakes
2" square steel tubing, 1/8" thick walls for the frame and cross members, except for the galley crossmember, which will be 2" angle.

Let me know what you think. Pretty much copied Tony's plans except the length and added the tongue mount tabs...maybe those are not needed? My other questions are about the axle...since this is not my area of expertise...I assume this setup will be adequate, given my trailer will be shorter, and most likely lighter, but will this axle be too much? Should I choose a different axle setup?

Thanks for your input.

[Tom&Shelly]

I am basing my design off of Tony's trailer plans in his book, except we are only going 9' long instead of 10'.

Let me know what you think.

Why only 9'? Whenever I modify dimensions in a design, I seem to mess something up somewhere along the line. Not a big deal--just wastes some material and time. (And usually I can re-use the material somewhere else, eventually.) But that's just me. I'd need a pretty compelling reason to cut off a foot.

Tom

[boulderv7]

I am basing my design off of Tony's trailer plans in his book, except we are only going 9' long instead of 10'.

Let me know what you think.

Why only 9'? Whenever I modify dimensions in a design, I seem to mess something up somewhere along the line. Not a big deal--just wastes some material and time. (And usually I can re-use the material somewhere else, eventually.) But that's just me. I'd need a pretty compelling reason to cut off a foot.

Tom

Mostly weight, cost and need. After I figured out everything we needed/wanted, it all fits in a 9' profile, so I figure why the extra foot? We basically decided we don't need/want the headboard in Tony's design, so that essentially dropped a foot from the profile. Hence the 9'. Are we gonna miss the extra foot? Maybe....will that mean I need to build another teardrop? Maybe....lol. That's ok with me.

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[saltydawg]

Well I would shift to 2x3 .085 wall rect tube and save some weight and be a little stronger over all. It saves about .3 lb for every foot of tube, which adds up when you figure all the lengths needed.

[boulderv7]

Well I would shift to 2x3 .085 wall rect tube and save some weight and be a little stronger over all. It saves about .3 lb for every foot of tube, which adds up when you figure all the lengths needed.

This is a good suggestion. I assume the 3" dimension would oriented vertically, correct?

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[saltydawg]

This is a good suggestion. I assume the 3" dimension would oriented vertically, correct?

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Yes, below is some deflection calcs. the important thing is the internal psi numbers, the flex does matter but the internal stress gives you how close to failure the steel is. Remember most mild steel is around 30-40 thousand psi strength. I included just for giggle 1x3 085, it flexes less than 2x2 120 but is a little higher stress.

[tony.latham]

Well I would shift to 2x3 .085 wall rect tube and save some weight...

It is a good suggestion. Just keep in mind that .083 is more challenging to weld than .120" --that's why I avoided it in the book. The other thing is that square tubing for the tongue works well for the removable coupler. But you could certainly stick with my tongue and the thinner rectangular steel for the frame.



Tony

[swoody126]

most materials come in 2' increments w/ metal coming in either 20' or 22' lengths neither of which divides by 9 evenly

so ... IMHO making a frame members roughly dividable by 2'± wastes very little/much less

plywood comes in 8' lengths x 4' widths

w/ frame members set on 24"± centers one can maximize the use of plywood

when targeting the 24" marks w/ a slight bit of fudge factor for mounting convenience you waste less material

stretching your 9' idea to 10' will consume virtually the same amount of labor ... like within 15 minutes± either way/operation/day's labor

just something i try to wrap my mind around when designing/selecting a project and i still end up adding to my collection of pieces of materials for tiny projects

Tony's headboard might could be quite handy ... specially if it didn't consume any extra materials

just this old cheapsteak's 2¢ worth this morning

BON CHANCE

sw

[boulderv7]

Yeah I'm gonna have a friend who welds by trade weld it up for me. I'll ask him about working with the thinner material. My experience with welding was limited to high school shop.

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[boulderv7]

Well I would shift to 2x3 .085 wall rect tube and save some weight...

It is a good suggestion. Just keep in mind that .083 is more challenging to weld than .120" --that's why I avoided it in the book. The other thing is that square tubing for the tongue works well for the removable coupler. But you could certainly stick with my tongue and the thinner rectangular steel for the frame.



Tony

most materials come in 2' increments w/ metal coming in either 20' or 22' lengths neither of which divides by 9 evenly

so ... IMHO making a frame members roughly dividable by 2'± wastes very little/much less

plywood comes in 8' lengths x 4' widths

w/ frame members set on 24"± centers one can maximize the use of plywood

when targeting the 24" marks w/ a slight bit of fudge factor for mounting convenience you waste less material

stretching your 9' idea to 10' will consume virtually the same amount of labor ... like within 15 minutes± either way/operation/day's labor

just something i try to wrap my mind around when designing/selecting a project and i still end up adding to my collection of pieces of materials for tiny projects

Tony's headboard might could be quite handy ... specially if it didn't consume any extra materials

just this old cheapsteak's 2¢ worth this morning

BON CHANCE

sw

Very good points all around. And something I have thought about. I'm still trying to keep the weight down though too, and would ideally like to be able to tow it easily with a vehicle with a 1500lbs tow rating. My wife wants to upgrade her sedan to a crossover type, but I currently have a Honda pilot with a 3500lb rating, so going a bit heavier wouldn't exactly be a deal breaker. I *think* 9' would be in that sweet spot for us, just big enough and just light enough...

But thats why I'm here, to ask questions and get feedback from people with experience.

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[tony.latham]

I *think* 9' would be in that sweet spot for us...

If I told my wife I was going to build a teardrop without a headboard, I'd be discussing the issue with a marriage counselor. Probably by myself.



They are that handy.

Tony

[saltydawg]

I'm still trying to keep the weight down though too, and would ideally like to be able to tow it easily with a vehicle with a 1500lbs tow rating. My wife wants to upgrade her sedan to a crossover type...

But thats why I'm here, to ask questions and get feedback from people with experience.

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if you want to save more weight make your cross members except the front one from 1x3 085, it weighs 2.1 lbs per foot. also make you tongue angles from it too. So a savings of almost a lb per foot over 2x2 120, and has less flex, and another 1/2 lb saved over 2x3 085. I built a frame like this, the total weight sans axle was under 150. It is plenty strong for a 1000 to 1300 lb trailer, if you get over 1300 I would not reduce the tongue angles to the 1x3.



edit before someone asks, I smear seam sealer over all my welds before I paint to help stop rust getting in any pin holes in the welds.

[boulderv7]

Now you guys got me thinking 10' is the way to go...and my wife is now like "the headboard would be nice"...

Thanks guys!



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[tony.latham]

Thanks guys!

Tony

[QueticoBill]

Interesting discussion. My plan is around 9'+ based on the roof being 10' and hatch 5' - three 5' x 5' pieces of baltic birch. I like eliminating a seam.

We all have different priorities and things we'd like to avoid.