Cutting EMT

[thecnwcaboose]

i've cut it with a roller style copper pipe cutter. worked nice. was slow as watching ice melt in a refer though..

I only use a tube cutter when i need to cut into the emt and perserve the wire and cable inside. otherwise hack away. have used those fancy battery saws from milwaukee and mikita on the job. pretty neat.

 

[joshuabardwell]

Don't forget that the length of the tubes isn't critical, but the distance between bolt holes is.
Use a jig that locates off of the first hole to position for the second hole.

Indeed. Here's a photo of the jig I built the last (first) time I made a dome.

That's the end that the already-drilled hole goes on. The other end, of course, is under the drill bit.

The first time I did this, I was building the dome for myself. Recently, someone asked me, "Where'd you buy that dome?" Upon hearing the answer, he asked what I'd charge to build him one. He has yet to actually come up with the money, but he's indicated that he's game.

Y'all may also enjoy reading about the hoist I constructed from hardware-store materials to make building the dome easier. Domes can be built "top-down" or "bottom-up". Top-down, you hang the dome from a crane or hoist and everybody works on the ground. Each time a level is completed, the dome is raised and construction of the next level is begun. Bottom-up, you start on the ground, and pretty quickly you're moving ladders around to finish the job. Even if you have a man-lift, top-down is faster, because you can have as many people working as you have tools. With bottom-up, you need a ladder or a man-lift for every worker, and there is still the additional hassle of having to lift up the struts, drop tools on people's head, fall off ladders, and so forth.

Here's a photo of the hoist itself, ready for construction of the dome:

And here's a photo of the completed dome with the hoist:

If you're interested, this blog post describes the logic behind why I think all of this is safe. Lots of load-limit calculations that may interest the engineering geeks aong us. This blog post details the hardware-store materials that I used to construct the hoist.

 

[CNC Dan]

I like that jig. And thats a good job flatening the EMT end. I bet you find the second dome will go much quicker and faster.

 

[Steave]

Sorry for dumb questions and I may be the only person on earth that don't know but what is the dome used for? Covered and used for green house? I don't see a door to enter? If you have time please inform me. Thanks (and don't laugh)

 

[k0ua]

Sorry for dumb questions and I may be the only person on earth that don't know but what is the dome used for? Covered and used for green house? I don't see a door to enter? If you have time please inform me. Thanks (and don't laugh)

Man you have a lot of nerve asking what the dome is for..... (I was kind of wondering too:ashamed

James K0UA

 

[Steave]

I searched the internet for a while before finally asking. I figured if nothing else I'd get a good laugh out of it anyway (at my expense)

 

[Soundguy]

ufo landing pad?

psychic radar reciever?

 

[Steave]

ufo landing pad?

psychic radar reciever?

I should have known I'd get an answer like this. I thought that might be what it was but didn't want to give away.
"Classified Info"

 

[Soundguy]

uh-oh.. did i leak it?

 

[sodamo]

I searched the internet for a while before finally asking. I figured if nothing else I'd get a good laugh out of it anyway (at my expense)

Count me in as well. Also what is the covering. Any finished pics?

David Sent from my iPad using TractorByNet

 

[joshuabardwell]

We run a theme camp that we take to Burning Man regional events in the southeastern US. Well, in principle, we take it to "events in the southeast," but in reality, we have only ever taken it to Alchemy, the Georgia regional, which is our home burn. In the years when we've had the dome, we have only gone to Alchemy and not any other regionals. If we were going to another regional, we would consider taking it. The dome is used as a common area for the camp, to hold workshops on various topics, and that sort of thing. At night, it's kind of like a night club or dance club.

Covering the dome was really challenging. The dome is 50' in circumference across the top. One common way of covering such a dome is to buy a decommissioned parachute silk of appropriate size. This works really well at Burning Man, which is held in the Black Rock desert near Reno, NV, because it almost never rains. The silk provides shade, but isn't really waterproof. We intended to buy a 60' square tarp, but every place we found that had them listed for sale actually showed out of stock when we tried to order it. Ultimately, what we ended up doing was buying three 10x30' tarps and a single 40x60' tarp. The 10x30' tarps make a "belt" around the base, and the 40x60' tarp makes a "hat" over the top. This still leaves some un-covered area near the door where rain can be an issue, but it's adequate.

The doorway is created by removing one of the horizontal poles from the second layer, leaving a diamond-shaped opening. We found that people tended to trip over the narrow bottom of the diamond, especially if they were... shall we say, not completely sober... so I fabricated some custom struts to create a doorway with vertical sides and an A-shape at the top. It compromises the dome's structural integrity slightly, but the tradeoff is worth it.

Here's a pic of the dome at this year's Alchemy.



The "front porch" off the front of the dome is a single 20x20' tarp with custom poles (just 2x2's really) and guy lines holding it up. It's not part of the dome, though.

 

[joshuabardwell]

BTW, someone suggested greenhouse. If you wanted such a thing, a hoop house would be a far better idea. Much easier to fabricate and put up, much easier to cover, and much better use of space, because you don't have 16' of height that you're not using. I have heard of folks using geodesic domes for chicken houses too. Makes it impossible to catch the chickens because there are no corners! Honestly, the main reason we built the dome was just because it seemed like a cool project and we wanted to give it a try. Domes are really fun and are a fantastic solution to a lot of different shelter-related problems, but they're not the right answer to every problem. For example, if you need the strength to support weight, such as hanging banks of speakers or light racks, a dome would be a good choice. But just for basic shelter or a greenhouse, they're kind of overkill.

 

[npalen]

Flattening and punching each end in one operation would be a good job for a simple dieset in a simple press. The holes could be located off of their respective end if the length tolerance was held close enough in the primary cutoff operation.

 

[joshuabardwell]

Flattening and punching each end in one operation would be a good job for a simple dieset in a simple press. The holes could be located off of their respective end if the length tolerance was held close enough in the primary cutoff operation.

Interesting. Are you suggesting that, with an appropriate die, I could do that in a regular hydraulic press? Where would the die come from? This is outside my area of previous experience.

 

[hosspuller]

Interesting. Are you suggesting that, with an appropriate die, I could do that in a regular hydraulic press? Where would the die come from? This is outside my area of previous experience.

Instead of a regular press ... a machine called a metal worker will speed up your production at a reasonable cost. Even cheap ... if you shop and purchase well.

here's a link to a video Edwards 25 Ton "Jaws Jr." Ironworker | Elite Iron Workers

At the end of the video, they show some specialized tooling .. though fleetingly.

 

[CNC Dan]

Flattening and punching each end in one operation would be a good job for a simple dieset in a simple press.

That gives me a thought. If you flatten the area where a cut is to be made first, you could make the cut with a shear. A shear is like bench mounted tin snips. For flattening, I think I would make a giant pair of pliers. As big as a pair of large pruning lopers. Should be much quicker than a hydrolic press.

 

[Steave]

We run a theme camp that we take to Burning Man regional events in the southeastern US.



Gotcha, thanks. It looks like an interesting build, nice work.