Technical Best way to cut thick steel

It's perfectly fine. Until it isn't. How many Incas and Aztecs working the stone setting field today? If you're in stone craft and haven't been here: put it on your life list. Damned if anyone can figure out how they did this. We're talking stones up to 200 tons so closely fitted you can't slide a piece of paper between them. I tried.There are three main walls-the longest is over 1200 feet. Oh, yeah. It's also over 12000 feet elevation so the available breathing air is sorta thin.
Sacsayhuamán, Cusco, Peru

 

Because it's Not INCA doing.
That's why they can't figure out how the inca did it.,,,
Like trying to explain how an ant carried an elephant because you found an ant and an elephant together.

Who did it and when they did it is an entirely different thought path.

 

"Sections were first built by the Kilke culture about 1100; they had occupied the area since 900. The complex was expanded and added to by the Inca from the 13th century" , but, if you believe in aliens, I guess they bopped over after doing the pyramids in Egypt. Bottom line, doesn't matter who did it, it's a pretty incredible feat of engineering and art, especially since they had no power tools, not steel tools and no draft animals. (Maybe just light sabers?)

 

I can't begin to even try to explain or understand how such a feat was accomplished. I can't waist my time on wild alien theories nor can I waist my time on equally assuming Primitive tool less accomplishments. These anomalies are beyond today's precision.

Yes this was done 1000s of years ago.
There are no "known" tools capable of this work at that time. Agreed assumption?
Some idiot who "knows" everything and based on that agreed assumption doesn't look for the tools or technology that obviously did it ,,,no but says it was done by some Egyptian's or Inca finger nails or softer stones. Never mind the saw marks, those aren't important just move along there's nothing to see here.


Then some other guys who at least refuse to ignore the obvious,,, well they say it must have been alien tools and technology. Nobody who "knows" everything bothers to look at the obvious and say "well, I just don't know but what ever they used must still be here. How did they harness it? How did they do it?

 

The answer is to bug them to fix the big plasma cutter! the torch would work fine as well.

Always wear your safety gear, you don't know when it will save your ass. It also helps with cumulative damage effects over time. Read some of the painting at home threads for details on that sort of thing. Lots of scary stories to the tune of "i've been doing this for years and I was ok... till i wasn't". Just don't screw around with your health and safety. You've only got one chance at living.

I'm porting my 392 heads right now, i wear the p100 double filter 3m mask i have along with hearing protection and safety glasses. Is it comfortable? not hugely. Do i blow iron filled boogers at the end of the night and sleep with rust in my lungs, ringing in my ears and crap in my eyes? Nope.

 

Research the theory of risk compensation. Safety nazis have caused more accidents than they've prevented. It's scientifically documented.

I gave my crew a monthly safety presentation on this theory that I titled "Safety Next".
The big boss showed up for it and I thought I was fired.
But even HE new it made sense.

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Edit to add: I am not advocating one way or the other.

 

[citation needed]

 

This happens in all areas, not just industrial safety... very common to see people do stupid things when equipped with safety equipment that they wouldn't have done otherwise. Lets call it over compensation. That being said, there's no fixing stupid. Gimpy has a solid point given the fact that no shop can afford the liability of a fool.

 

A few below. There is a definite balance between what regs are safe and what regs are ridiculous.
As a safety trainer I can tell you honest, most regs are to mitigate liability, not keep you safe.

As
Http://www.selectinternational.com/safety-blog/risk-compensation-affects-personal-safety

Adams, CF (1879). Notes on Railroad Accidents. G.P. Putnam's Sons. LCCN 06029469. OL 7162865M

Hedlund, J. (2000). "Risky business: safety regulations, risk compensation, and individual behavior". Injury Prevention. 6(2): 82–89. doi:10.1136/ip.6.2.82. PMC 1730605 [https://upload].

Lund, AK; Zador, P (1984). "Mandatory belt use and driver risk taking". Risk Analysis. 4: 41–53. doi:10.1111/j.1539-6924.1984.tb00130.x.






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True enough, but I can tell you without doubt, the way he cuts those discs tells me he is no moron.
He knows the risk and proceeds accordingly.

I would call that a master.

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This is not a citation.

This is a Statement of Theory.

Show me reliable data, from which a statistically valid conclusion can be drawn.

Bonus points if you can find a behavioral study that actually related to the current topic.

 

It's called the Theory of Risk Compensation.
Admittedly, I overstepped when I stated it's scientifically documented.

It is statistacally documented with strong correlating data.

As stated, I don't advocate one way or the other. A grown man makes his choice.
Personally, I'm a glove free brazer, and gloved cutter. Depending on my assesment of risk and the benefits for or against at the time.

And those are citations, from studies.

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Correlation is not causation.

A good example: Every time I see umbrellas out all over the place, it is raining. Umbrellas cause rain.

 

A DoAll band saw with a good blade will cut 3/8" easily

 

I`d dog those plates down to the rotary table and walk around the edge with a 2 flute slotting cutter. But that`s just me.

 

Exactly. I want to see examples of where properly using safety equipment led to accidents which would not have happened if no precations had been undertaken. I am sure a few exist,somewhere, but not a statistically documented sample

 

Can't I just burn these plates for him?

Well,, fall protection equipment sales go up and up to record high sales. An easily re searchable fact. And fall related injury and death incidences go up and up as well - equally easy to validate . Those incidences should go down. Those two statistics are there but I don't think a full study has been done to put the 2 together.
Parse that a bunch of different ways and say it's improper use, or tripping over the lanyard. Or there's more people in the air and averages must go up as sales and people do or the amount of sales although high doesn't really correspond to the amount of people in the air.

Full harness and Tie off at 4' is silly, drop a screw come down off the ladder and pack your testicals or dangle 2" off the ground. Come off a large loader and get slammed back into it. Walk across the roof and get clotheslined because someone stood up.

Not really a safety requirement, more of a security issue but visible name tags and passes worn on or around the neck lanyards are dangerous too. Yep it depends on what you're doing but the dumbest crap happens in the dumbest places - a nurse got her tag stuck in a bed rail and wound up with a broken jaw and some structural neck injuries. Car show passes, concert/event tickets and a bunch of other stuff on these things and Break always would be much better.

 

Hey thanks for keeping my thread alive guys!

Just got back from school. First I tried the bigger plasma cutter, which was working but no better than the small Miller, wouldn't go through. It's the one on the left of the mig, 1start s60 or something. Out came the cutting torch. Got one circle cut, not pretty but good enough for this project. Very slow going, and no matter how slow I went after 2-3 inches it would not cut any more without preheating again. Maybe that's normal? I had the oxy set at 20, acetylene at 8, the tip says 3=1-101 I believe. Any ideas to make the second one better welcomed...

 

What did the instructor at school say?
20 is too low on the oxygen, I want about 40. I have a Harris torch and would use a 1 tip to hand cut a circle like that. 0 tip if it were a straight line or some kind of circle jerk apparatus described above or a burning machine.
You want extra heat because you're moving your hands in an xy axis and a little variation expected and a little extra heat needed to keep up or cover up that variation.

 

Get rid of the surface rust on your cut line for a start,it will make a difference ,
Drill a start hole as said before and lean your torch backwards slightly while cutting.You are going to have increase the heat and feel for your speed,to fast and it will happen as you describe.
Looks like a good first time attempt though.

 

Thanks guys. Instructor gave me the 20 and 8 pressure numbers, other than that he was busy doing other stuff. It's an auto body class, I should probably take it up to the welding class. But, a friend stopped by last night and says he has a fancy circle cutting jig and tip, going to go have a look later today.

 

My Son is a Boilermaker in a shipyard, as an apprentice in the early weeks they would have him cut 3/8 steel blanks to cap off Pressure Piping. after over 300, they moved him on to the waterjet. To this day he is very handy with the old Gas axe. Practice makes you better. learn to use the basics
they will serve you well in the years to come. I am a retired Shipwright from the same Yard, We had it way easier , our blanks ( non pressure) were made from plywood and cut on a bandsaw

 

Yeah, 10 pounds on the acetylene, 40 on the oxygen. Constant speed, constant motion. Works every time. Pay attention to what Rex Stallion said about practice. I've been practicing about 60 years and I've almost got the hang of it.

 

Metal cutting bandsaw with bi-metal blade, slow speed. Will do a nicer cut than torch.

 

This guy would know how it was done, 5 feet tall and 100 pounds but moved 30 ton blocks of coral
https://www.historicmysteries.com/coral-castle-miami-florida/

 

Anytime I cut any radius on my band saw it wipes out the blade. I can cut countless linear feet with one blade for weeks, beveled , miters, any kind of straight cut. Or I can cut about 10 mins worth of a radius, don't matter if it's 10' radius or 10" radius it eats blades. I complained to my blade rep and he said "so don't cut a radius, band saws blades are not made to do that because it flattens the set on the out side "

It really pisses me off when my guys swap a new blade in and cut a curve. 100 times I tell them straight lines only and jig saw or plasma the radius.
So Now when I hear the saw blade bitching I grab the phone, shut the saw off and tell them to order a blade on their credit card,,, do it right now I'm not kidding.

 

My pal lent (gave actually, he's downsizing) this. The tip is much larger than the one I used last Wednesday, and with more PSI hopefully will cut better. Circle jigs are a bonus. More to follow.

 

I have been using this for the last 49 years. Simple to make, using an electrical wire clamp.

 

… AKA a split-bolt connector.

 

Thanks for the clarification Steve, I am a welder not an electrician.