Question about building a steel dolly

[grobierno]

Hello, I am 71, a scrap steel artist. I purchased a welder in January and although certainly still learning, have reached the point that I am now using welding to assemble components instead of using brackets and bolts. I hope I qualify to post here, if not please direct me.

My question is not about welding. I want to build what I will call a small dolly, fundamentally (operationally) like a furniture dolly, but with a full floor/deck, and large wheels for exterior terrain and a handle for manual or lawn tractor pulling. I'm looking for guidance regarding steel plate floor thickness as it relates to supports under it. I want to be able to make my sculptures on it and have part of my weight (a knee or two) on it while I'm working.

Dolly Size: 3' x 3' My weight: 215 lbs Typical Sculpture Weight: 50 to 250 lbs

My store-bought welding table top is 2' x 3' and about 5/32" thickness. It has 1-1/2 " x 3/4" x 3/32" rectangular tube supports around the perimeter and one across the middle. So I could use these specs to plan my dolly, but don't know if they are ideal, too little, or overkill for the dolly requireents.

 

[drawoh]

grobierno,

Are you constrained for weight? The heavier your dolly is, the harder it will be for it to tip over. Do you have to lift it?

Do your wheels have to be under the dolly? If they are outside, you have a larger footprint, a lower centre of mass, and more stability.

For stiffness, you need gussets underneath, which I presume, you will weld in place. How thin a piece of steel can you apply a high quality weld bead?

 

[grobierno]

Thanks drawoh,

The die is cast, and I can relate to your last question due to my limited welding experience.

I bought 10ga for the 3' x 3' "floor", and 14ga for the 1" x 2" rectangular tube gussets which will go around the perimeter and also form a cross in the center (like a 4 pane window grid).

When comparing my options for rectangle tube at the metal supply house, I picked 14ga over .0625 for the very reason you referenced.

Because I am not an engineer, I rely on build over weight. This will be 90-some pounds. If I'm using this in 10 years, I'll make a dolly for it.

 

[lucky-guesser]

Assuming you have the vertical space to do so, get your 1x2 bracing tubes such that the 2" face is vertical, that will give you the most strength the resist flexing. Your 10ga plate with 250+ lbs in the center would certainly be prone to bowing on its own, so your tubes will be what prevents that. A simple "+" may be enough, but if you have the material you may want to add more bracing than that. You can always build it with the one cross and see how it feels, and add bracing as needed.

My style of welding is to turn up the voltage and burn it in. Not always pretty, but nothing ever breaks. That said, "burn it in" is more like "burn a hole through it" when using sheet metals like your 14ga. If your art typically uses thinner materials then you are probly used to it, but if you are new to thinner materials then be prepared to turn down your welder, and if nothing else take your time and allow the part to cool as needed.

 

[LittleInch]

Do you have a sketch or a drawing or even some pictures?

Words are useful, but it's difficult to know what bit of this dolly you're having trouble with.

Large wheels and handles are not standard and hence I think you might be better off adapting something that works in your terrain rather than building one from scratch, which although it would be more fun, is a lot of hard work.

Or at least do your research on one you can buy in the local hardware shop or off the internet to see how they've made it.

A lot also depends on your substructure which looks a bit weedy to me. Also think about point loads and forces. A 200 kg force is quite a lot.

Also a 45kg empty weight is a decent weight to pull across rough ground without your sculpture on it. You might end up needing larger wheels to go over bumps and even a small slope will prove difficult to pull. You can probably only pull about 20-30 kgf and that's with very good grip. Grass or something else you could be down to 10-15max.

You might have got a bit more traction in the engineers with hobbies forum, but this one will be ok.

 

[XR250]

My steel guy gives me crap when I call it a "welder"

He is the "welder" using a "welding machine"

 

[grobierno]

My style of welding is to turn up the voltage and burn it in. Not always pretty, but nothing ever breaks. That said, "burn it in" is more like "burn a hole through it" when using sheet metals like your 14ga. If your art typically uses thinner materials then you are probly used to it, but if you are new to thinner materials then be prepared to turn down your welder, and if nothing else take your time and allow the part to cool as needed.

I hear that. I plan to make the rect tube support structure first on my table. I have envisioned the welding process and am now practicing (with mixed results) vertical uphill tacking which will hopefully get it completely together strong enough to manipulate the orientation repeatedly so I can do final welding as horizontal fillets. I have made only two sculptures using welding - it worked out pretty good, and the component's thicknesses range anywhere from a barrel hoop to near 1/2". One of them is 95 lbs. and a bugger to move around. This is one reason I'm making a dolly.

Large wheels and handles are not standard and hence I think you might be better off adapting something that works in your terrain rather than building one from scratch, which although it would be more fun, is a lot of hard work.

Or at least do your research on one you can buy in the local hardware shop or off the internet to see how they've made it.

A lot also depends on your substructure which looks a bit weedy to me. Also think about point loads and forces. A 200 kg force is quite a lot.

Also a 45kg empty weight is a decent weight to pull across rough ground without your sculpture on it. You might end up needing larger wheels to go over bumps and even a small slope will prove difficult to pull. You can probably only pull about 20-30 kgf and that's with very good grip. Grass or something else you could be down to 10-15max.

I did not respond until this evening because I was previously too busy to do it right with the amount of attention to detail and interest and fun that this can be.
I have planned the structure based on my welding table specs, I feel fairly confident in the outcome. Funny story about the wheel size. I've done a few interesting projects involving casters. I made what I call a 10' homemade Nanawall. Hanging such a thing was beyond me so I supported it from the floor with MacGyvered gate casters. I also made a big wooden workbench, and to move and plant it, I combined a certain caster with a certain hold-down toggle clamp so I can operate it with my foot. The ones found online looked like they would bend during the first use. So, over confident with my bit of experience and observing that garden carts have 10 - 13" wheels, I figured I'd use a total locking 8" caster wheel. Found one online at Harbor Freight, went to look at it and laughed out loud. It might work but would look hilarious. I ordered 6" knobby ones that should handle the terrain I have, and just got wheel rotation locking ones, and will use a couple of floor locks to plant the dolly when I'm working on it.

You might have got a bit more traction in the engineers with hobbies forum, but this one will be ok.

Indeed, this one has been better than OK - thanks guys!

 

[Joyaloorg]

I hear that. I plan to make the rect tube support structure first on my table. I have envisioned the welding process and am now practicing (with mixed results) vertical uphill tacking which will hopefully get it completely together strong enough to manipulate the orientation repeatedly so I can do final welding as horizontal fillets. I have made only two sculptures using welding - it worked out pretty good, and the component's thicknesses range anywhere from a barrel hoop to near 1/2". One of them is 95 lbs. and a bugger to move around. This is one reason I'm making a dolly.

I did not respond until this evening because I was previously too busy to do it right with the amount of attention to detail and interest and fun that this can be.
I have planned the structure based on my welding table specs, I feel fairly confident in the outcome. Funny story about the wheel size. I've done a few interesting projects involving casters. I made what I call a 10' homemade Nanawall. Hanging such a thing was beyond me so I supported it from the floor with MacGyvered gate casters. I also made a big wooden workbench, and to move and plant it, I combined a certain caster with a certain hold-down toggle clamp so I can operate it with my foot. The ones found online looked like they would bend during the first use. So, over confident with my bit of experience and observing that garden carts have 10 - 13" wheels, I figured I'd use a total locking 8" caster wheel. Found one online at Harbor Freight, went to look at it and laughed out loud. It might work but would look hilarious. I ordered 6" knobby ones that should handle the terrain I have, and just got wheel rotation locking ones, and will use a couple of floor locks to plant the dolly when I'm working on it.

Indeed, this one has been better than OK - thanks guys!

quite detailed clarifications

 

[LittleInch]

I hear that. I plan to make the rect tube support structure first on my table. I have envisioned the welding process and am now practicing (with mixed results) vertical uphill tacking which will hopefully get it completely together strong enough to manipulate the orientation repeatedly so I can do final welding as horizontal fillets. I have made only two sculptures using welding - it worked out pretty good, and the component's thicknesses range anywhere from a barrel hoop to near 1/2". One of them is 95 lbs. and a bugger to move around. This is one reason I'm making a dolly.

I did not respond until this evening because I was previously too busy to do it right with the amount of attention to detail and interest and fun that this can be.
I have planned the structure based on my welding table specs, I feel fairly confident in the outcome. Funny story about the wheel size. I've done a few interesting projects involving casters. I made what I call a 10' homemade Nanawall. Hanging such a thing was beyond me so I supported it from the floor with MacGyvered gate casters. I also made a big wooden workbench, and to move and plant it, I combined a certain caster with a certain hold-down toggle clamp so I can operate it with my foot. The ones found online looked like they would bend during the first use. So, over confident with my bit of experience and observing that garden carts have 10 - 13" wheels, I figured I'd use a total locking 8" caster wheel. Found one online at Harbor Freight, went to look at it and laughed out loud. It might work but would look hilarious. I ordered 6" knobby ones that should handle the terrain I have, and just got wheel rotation locking ones, and will use a couple of floor locks to plant the dolly when I'm working on it.

Indeed, this one has been better than OK - thanks guys!

Just post some photos of the finished article or the frame at least!

 

[grobierno]

Just post some photos of the finished article or the frame at least!

Sounds good. I appreciate the chance to do that. As a beginner, I've been practicing the fabrication-like welding procedure I'll be doing. I'm fairly good at tacking, but need a little more time on elongated fillets, and by that I mean something that works fine but also looks good. When I post pics, I'll include shots that reveal the brutally honest situation on that. Completion will be weeks away, not days or months. I'll send frame pics first.

Something you folks might appreciate - to judge dolly floor and support thickness and configuration, I first layed out boards on the floor to mock up the perimeter of the rectangle tube support grid, then put the floor on it. Got on it... no way, as I suspected. Then I added a cross in the middle and it felt good even as I bounced a little. Then removed all that and put a piece of the rectangle tube on two boards that represented their supporting components (the caster wheels), bounced on that and it felt really good. Don't get me wrong, I'm not adverse to actual measuring. I did a major tile job, floor, walls, walk in shower, and to confirm the acceptability of floor deflection, I measured it between the ceiling and floor of the room below. My joist platform was sound with respect to best practice specs - I wanted to know the deflection in the platform as a whole.

Just for S&G, attached are pics of the homemade Nanawall I mentioned, complete with uninvited guest.

 

[grobierno]

forgot to mention the most interesting detail about the 10' homemade Nanawall project which consists of two 60" sets of two bifolding 30" french doors, inner door hinged to jamb, outer door hinged to inner door. - Even with the gate casters I assumed I would be asking too much of the individual door's construction, so I routed right angle channels on all four "corners" and screwed 1/8" thick right angle steel braces in place, then puttied over. Worked like a charm