Learning to build a 5x8 square drop

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Learning to build a 5x8 square drop

Postby DesertApprentice » Wed Jul 28, 2021 11:24 am

After contemplating and discussing for a while viewtopic.php?f=62&t=73811, I finally tip-toed into the frame build.
Barely one day into the build, I already came to a halt. The frame doesn't appear to be a true square :( This is my first time welding for real.
I have a big decision to make: should I cut it up and redo it? That's what I lean towards. I'd like to hear advice.

It's a big decision, let me list all the details here. Assuming my measuring tools are "accurate" and I have taken the correct measurements, here is what I got:
frame-0.jpg
frame-0.jpg (179.7 KiB) Viewed 1195 times

Distance measurements - width: top side 5'-1/16, bottom side 5', length is 8'+1/16 for either side. Diagonals are 1/8 off. Details are below:
Width:
top of the frame is 5' - 1/16
bottom of the frame is 5'
Length:
both left and right are 8' + 1/16 (same)
Diagonal:
One is 113", the other is 113" + 1/8. That's 1/8 off.
Square angle measurements - the square tools indicate all corners are less than 90 deg, which is impossible. I tried 3 different square tools, they all indicate the same :( All sides have to be bowed inward for that to happen, that's practically impossible (I have attached an exaggerated illustration). I have manually "verified" the square tools, they all seem to be correct (drawing two overlapping vertical lines while flipping the square tool horizontally).
frame-angle.jpg
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I'm stumped. I'm leaning towards cutting it up. Any advice is appreciated!
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Re: Learning to build a 5x8 square drop

Postby tony.latham » Wed Jul 28, 2021 11:56 am

Well... 1/8" on the diagonals is fine for the frame.

What's most important is getting the axle squared with the tongue.

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I use three plumb bobs for this. Clamp one side of the axle in place and adjust the other side. Don't try to fight both ends.

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Re: Learning to build a 5x8 square drop

Postby TimC » Wed Jul 28, 2021 12:00 pm

- Relax

- Listen to Tony

- Have a barley pop and get back to it
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My First Benroy Teardrop Build Thread - A 5x8 Woodie - http://www.tnttt.com/viewtopic.php?f=50&t=63575
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#3 My son's Benroy Foamie team build - Started July '20 - http://www.tnttt.com/viewtopic.php?f=50&t=72877

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Re: Learning to build a 5x8 square drop

Postby DesertApprentice » Wed Jul 28, 2021 1:40 pm

tony.latham wrote:Well... 1/8" on the diagonals is fine for the frame.

What's most important is getting the axle squared with the tongue.

I use three plumb bobs for this. Clamp one side of the axle in place and adjust the other side. Don't try to fight both ends.

Tony


Thank you very much for your response. I'll definitely square the axle and tongue carefully.

I also realized I should have cut the width to 59 1/2". I believe you said there may be challenges with materials with the exact 5' frame. If I want to change, this is the last chance.

If exact 5' is not a big problem, I'll move on with the Timbren axle install. Will be another learning process. I have been checking online resources and youtube links. I'm hoping no big surprises, fingers crossed!

Thank you very much!
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Re: Learning to build a 5x8 square drop

Postby DesertApprentice » Wed Jul 28, 2021 1:43 pm

TimC wrote:- Relax

- Listen to Tony

- Have a barley pop and get back to it


I'm indeed very nervous. Until it's finished, many more things to learn ahead. Hope my confidence grows with the build :R
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Re: Learning to build a 5x8 square drop

Postby tony.latham » Wed Jul 28, 2021 2:59 pm

I also realized I should have cut the width to 59 1/2".


That's not standard. I do that primarily so that an aluminum-clad teardrop doesn't rest on its lower trim.

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Re: Learning to build a 5x8 square drop

Postby MickinOz » Wed Jul 28, 2021 3:01 pm

So you set out to construct an 8 x 5 frame with mitred corner joints.
It came out 8' 1/16" x 5' 1/16"., and 1/16" out of square.
That's bloody good work mate.
Reckon a pro would do any better? Pros probably work on a bigger tolerance than that.

You know 1 eighth inch/3mm across the diagonals is actually only 1 sixteenth inch / 1.5mm out of square, right? i.e. you'd only have to pull the long diagonal 1/16 of an inch to get the two sides to match.
As square as you'll ever get.

As for the potentially bowed in sides, don't stress.
Run a string line and see if the long sides are straight.
If the long sides bow in a bit, cut your cross members long enough to spread the sides back to straight. They'd have to be a very long way out to be unable to flex the long sides straight.
Or build the cabin on top. That way you can run your outer measurements at the 60 inch mark.
The only question I have - did you manage to build the frame without a twist?
i.e. when you sight across the side rail from one side, is the other rail parallel?
Looks pretty good from here. :lol:
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Re: Learning to build a 5x8 square drop

Postby TimC » Wed Jul 28, 2021 4:37 pm

DesertApprentice wrote: ...

I'm indeed very nervous. Until it's finished, many more things to learn ahead. Hope my confidence grows with the build :R


You are doing fine. Welding scares me so I hired out the custom chassis on my first teardrop. The pro welder produced a "square" 5x8 frame but I didn't notice until I was adding the floor that the roadside front corner took a 3/4" nosedive from about a foot from the corner. A few shims and some trim along the bottom and nobody but me knows. Well the tnttt world knows...

I don't use custom chassis' anymore because the cost of my first was double what a NT trailer costs even after wheel upgrades. If I had the skills I would weld my own, but I prefer focusing on the rest of the build.

Keep picking away at it and ask, ask, ask questions.
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My First Benroy Teardrop Build Thread - A 5x8 Woodie - http://www.tnttt.com/viewtopic.php?f=50&t=63575
My Second Teardrop (partial) Build Thread - Started August '16 - http://www.tnttt.com/viewtopic.php?f=50&t=66939
#3 My son's Benroy Foamie team build - Started July '20 - http://www.tnttt.com/viewtopic.php?f=50&t=72877

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Re: Learning to build a 5x8 square drop

Postby DesertApprentice » Wed Jul 28, 2021 5:20 pm

TimC wrote:
DesertApprentice wrote: ...

I'm indeed very nervous. Until it's finished, many more things to learn ahead. Hope my confidence grows with the build :R


You are doing fine. Welding scares me so I hired out the custom chassis on my first teardrop. The pro welder produced a "square" 5x8 frame but I didn't notice until I was adding the floor that the roadside front corner took a 3/4" nosedive from about a foot from the corner. A few shims and some trim along the bottom and nobody but me knows. Well the tnttt world knows...

I don't use custom chassis' anymore because the cost of my first was double what a NT trailer costs even after wheel upgrades. If I had the skills I would weld my own, but I prefer focusing on the rest of the build.

Keep picking away at it and ask, ask, ask questions.


I was worried I have been asking too many silly questions. Great to hear your encouragement. I'm going to finish up the frame and move on to the Timbren alxe-less suspension. I will keep updating progress here.

Thanks again!
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Re: Learning to build a 5x8 square drop

Postby DesertApprentice » Wed Jul 28, 2021 5:21 pm

MickinOz wrote:So you set out to construct an 8 x 5 frame with mitred corner joints.
It came out 8' 1/16" x 5' 1/16"., and 1/16" out of square.
That's bloody good work mate.
Reckon a pro would do any better? Pros probably work on a bigger tolerance than that.

thank you for the encouragement!
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Re: Learning to build a 5x8 square drop

Postby rjgimp » Thu Jul 29, 2021 1:08 am

MickinOz wrote:Looks pretty good from here. :lol:


:lol: That's easy for you to say, mate. You're 12,000 miles away! :R
-Rob


I hope to make it to a Procrastinators Anonymous meeting someday...
just as soon as the steering committee gets around to scheduling one!
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Re: Learning to build a 5x8 square drop

Postby MickinOz » Thu Jul 29, 2021 4:03 am

rjgimp wrote:
MickinOz wrote:Looks pretty good from here. :lol:


:lol: That's easy for you to say, mate. You're 12,000 miles away! :R

But, my optometrist says I'm long sighted mate :D
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Re: Learning to build a 5x8 square drop

Postby DrewsBrews » Mon Aug 02, 2021 6:34 pm

Weld shrinks when it cools. This usually winds up pulling both pieces towards the welded side. If you welded the inside of the corners first then, yes, it would bow all the bars inwards. I'd bet the longer measured length was one of the corners you started on.

https://www.youtube.com/watch?v=2vuGlcbDwKY

I would not sweat 1/8" on the diagonals. That is very close. That method of measurement exaggerates how out of square it actually is IMO.
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Re: Learning to build a 5x8 square drop

Postby DesertApprentice » Thu Aug 05, 2021 7:42 pm

DrewsBrews wrote:Weld shrinks when it cools. This usually winds up pulling both pieces towards the welded side. If you welded the inside of the corners first then, yes, it would bow all the bars inwards. I'd bet the longer measured length was one of the corners you started on.
https://www.youtube.com/watch?v=2vuGlcbDwKY
I would not sweat 1/8" on the diagonals. That is very close. That method of measurement exaggerates how out of square it actually is IMO.

DrewsBrews - Thank you for your response. I'm going to stop worry the minuscule measurement errors. I actually cut it up and re-welding it now. I'm putting the inside cross members before the final welds. The heat appears to alter the dimension even with the spot welds. I'm learning to put all these into perspective now.

I think I'm getting a new worry now :o I need expert input again.

I plan to use my Rubicon JL factory 33" tires for the trailer. That was actually part of the motivation I started this project after I lifted my Jeep to 37" tires. I ordered the Timbren axle-less suspension with hubs/brakes. According to the Timbren document, the distance between the trailer and the lug nut thread hole (indicated as "K" in the diagram) is 8.5". I just measured my wheel, from the lug nut thread hole to the tire outside wall, it's 7+5/16". Theoretically, the gap between the tire and trailer frame is ~11/16". The fender wall also need to fit into this space. Is this feasible?
timbren-diag.png
timbren-diag.png (318.64 KiB) Viewed 939 times
tire.jpg
tire.jpg (197.96 KiB) Viewed 939 times

I'm worried the gap is too narrow.
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Re: Learning to build a 5x8 square drop

Postby DesertApprentice » Thu Aug 05, 2021 9:32 pm

gee, it's getting worse. I tried to do a mockup dry fit, I noticed a bolt sticks out 3/4" from the frame with the Timbren assembly, the spindle is 14" away, so this bolt lines up exactly against the tire wall.
axle-bolt.jpg
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I'm not sure if I can even fit the tire in, let alone any gap between the tire and the frame. Any possible workaround other than going to smaller tire? I swear I saw in youtube, some teardrop was using Timbren axle with 33". Not sure how they did it. Maybe my tire is just too fat, i have 285/70/R17.
I did some quick reading on wheel spacers, not sure I want to go that route.
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