Design and fabrication chat

[mrblaine]

We all do lot of fab and need to understand some aspects of design rather than just throw lots of material at something. It would help if the folks I've discussed this with hold back some until we get some input. So, this is simple, what is needed on the below project and what was done that is fully unwarranted? Or, put another way, what would you change?

 

[MountaineerTom]

All those vertical supports under the center of the highest platform seems excessive, from an untrained eye.

 

[Apparition]

All those vertical supports under the center of the highest platform seems excessive, from an untrained eye.

My eye sees way too much steel, supports that don't do much and steps that aren't all the same.

 

[MaximusLJR06]

The second to last step from the top is smaller than the rest.

 

[mrblaine]

All those vertical supports under the center of the highest platform seems excessive, from an untrained eye.

What about the angle braces?

 

[mrblaine]

The second to last step from the top is smaller than the rest.

We're not worried about workmanship. We are looking at the overall design.

 

[mrblaine]

My eye sees way too much steel, supports that don't do much and steps that aren't all the same.

How sturdy is the platform or how much will it move when you work on it?

 

[MountaineerTom]

What about the angle braces?

Looks like there are two different sizes and only on two of the four sides of the tallest section.

Seems like it would help with stability, but would some smaller solid triangles in all the corners work better?

 

[Apparition]

How sturdy is the platform or how much will it move when you work on it?

Without knowing the specifics it looks fairly sturdy, assuming we aren't having elephants walk on it, but only because it's had so much thrown at it. I think you could make it just as sturdy, likely more, if you understand load path with much less material.

Are we going to compare this to some of the cages people put in jeeps?

 

[bucky]

I’m an Old Guy and that many narrow steps with no hand rail scares me. Did you build that so that you can preach to the masses?

 

[freedom_in_4low]

Mine probably would have looked something like this:

(delete the red, add blue)

 

[mrblaine]

Mine probably would have looked something like this:

(delete the red, add blue)

View attachment 517967

Why does it need angle braces?

 

[mrblaine]

I’m an Old Guy and that many narrow steps with no hand rail scares me. Did you build that so that you can preach to the masses?

I don't recall you being that blind or that much of a dick. Did the boat prop escape your attention? It is a platform for working on boats that I had nothing to do with designing or building.

 

[freedom_in_4low]

Why does it need angle braces?

It might not. I'd build the rest of it first and add those if it wants to wobble once it has me on it.

 

[Blackjack]

Could easily halve the number of vertical supports but needs some angle gussets to reduce side racking.

 

[Shank]

Why does it need angle braces?

With the steps, it likely doesn't.

 

[mrblaine]

Could easily halve the number of vertical supports but needs some angle gussets to reduce side racking.

There's the answer I was looking for.
I tried to explain that there is enough bracing at the tube butt joints that just the first step provides ample resistance to fore and aft movement as you bounce up and down the steps. As such, each additional step arrangement only improves that.

I was not able to get my description adequately explained verbally even with a basic picture.
I pointed out that there is enough "gusseting" in the section I circled in green to fully resist any forces that would create unwanted movement. I failed in making them understand that properly.

So, I built that section in a few minutes to be roughly 6" x 7" out of 1" x .100 wall square tube and added attachment points at opposite corners.

I hooked those up to the front bumper of the Unlimited and the engine hoist and picked the front end up off of the ground with zero deflection corner to corner in the rectangle. In fact, the little picture is showing the weight of the front of the rig on the rectangle.

Each repetition of that feature only increases the resistance to movement. It needs no angle braces whatsover to prevent that.

 

[srimes]

1st, it looks like it was a "this is the material we have, make something work" build.

2nd, Those are very slender columns and subject to buckling.

 

[Apparition]

These look to have not collapsed over the years.

 

[Apparition]

2nd, Those are very slender columns and subject to buckling.

That's why I was concerned about elephants