Technical Best way to cut thick steel

I need to cut two 19" diameter disks out of 3/8" steel. I tried last night with the plasma cutter we have at school but it wasn't up to the task. It's a small Miller about the size of a breadbox. There is a larger one maybe twice the size but it's not working right now. Other option is a standard cutting torch. which I would make some sort of compass arrangement for. I don't need a perfect edge but not too funky, and I'm no pro with the torch. I have a small metal band saw but it's probably not up to it either.

Someone suggested a water jet, which I don't have access to. Would that be the thing? Any idea what a shop would charge to do it?

 

The quickest way to answer your last question is to call a couple of steel shops in your area and ask.

 

Cutting torch just clean the tip and make some kind of circle cutter attachment and go to town

 

Rough cut to size, drill pivot hole in center. Lock torch in vise . Move material slowly around pivot. A 2nd set of hands helps.

Sent from my LG-TP450 using The H.A.M.B. mobile app

 

Thanks guys. In addition to the pilot hole and strap, would it make sense to use something to hold the torch a consistent distance from the work as I go around?

 

Wouldn't hurt. Anything to make the job easier in the long run.

 

Two more options. Cut a disc out of 3/4"/1" plywood vise grips it to your metal and follow around with the torch. Depending on how precise to 19" you need, you can cut plywood less than 19". Then you are set for second piece. Also, if you had access to those wire wooden spools the smaller ones maybe see what the diameter the end cap is .

 

I'd build a quick-n-dirty trammel and put a small wheel or even a bearing on the end to rest my torch hand on. tack the base to the plate so it don't shift. Use the trammel to put a nice chalk/sopastone line down to follow first.

 

go to google images, search

torch circle attachment

for some ideas...

 

Call Kevin at Standard Metal Products. Ask about waterjet cutting.
Tell him Brian at Cruise sent you.

 

Here's a guy cutting circles with a oxy acetylene torch and a circle cutter.
Very easy with the proper sized torch tip (#1 for 3/8" steel plate.)

Just be sure to wear proper welding gloves using the torch, unlike this moron.

 

Safety is very important but his hands are nearly a foot away from the flame. Hardly a moron IMHO

 

Well, as I have found out when I was a teenager with no tools, it sure as hell ain't no damn hacksaw!

 

Regardless of the distance from the flame we teach our apprentices the importance of safety.

No work gets done in the welding shop without gloves on and other PPE, including long sleeves, no exposed skin.

Having seen first hand ( no pun intended)
the results of torch burns or radiation burns from welding arcs I stand by my comment.


So yes IMO a moron.

 

Being a welder since 1951 starting with USN training,------Go with the first comment----Take the material to your local welding shop.

 

Man, at 19" I'd just hand burn those
Soap stone line, prick punch and burn it. 20 min job

 

Get magnet to build your turning device off of. Something like the magnetic parts bowl that Harbor Freight sells. No need to drill a center hole.

 

No matter what, the safety Nazis always have to make their presence known. While cutting with a torch has its dangers, in this particular demonstration, the flame is far enough away from the operator to greatly minimize any chance of being burned. I'm sure, in your shop, you have your standards. PPE, fall arresting harnesses, full body condoms and everyone covered with bubble wrap. The man could have worn gloves, but he choose not to. By definition, this doesn't make him a moron, perhaps a tiny bit careless. I retired from construction. Welded on high rise office towers, water treatment plants, the L.A. Metro Rail, several prisons, etc., etc. I often burned with a torch. Sometimes with gloves, very often, without. I never, not once, injured myself as a result. I guess I'm a lucky moron

 

Thanks again for the suggestions guys. Gonna try it again next week at school (free gas). If I fail I'll just send it to 31Vicky, 20 minutes at $25/hr., can't beat that!

 

I could probably take offence to your nazi comment Carl but instead I’ll just consider the source and let my career as a professional tradesman and educator speak for itself.

You can also be proud of your career, what you can’t be proud of is your lazy attitude towards safety.

I believe you know better and you said it better than I could yourself.

 

I think what people don’t realize Larry is that we have to train our future tradespeople with the utmost in safety practices. How they choose to use that is up to them. I’m sure we have all gotten away with doing things we shouldn’t ,however some aren’t that lucky and it’s not an excuse to ignore safety.


Sent from my iPhone using H.A.M.B.

 

You know nothing of the "source". BTW educators usually spell "offense" properly. I too was a professional tradesman, as stated in my previous post. Yes, you could take "offence" to the Nazi deal as I'm fairly certain that you believe that it was some sort of racial/ethnic/political attack. It was not. It's pretty obvious that you are going to beat this to death with tales of death, destruction and other unspeakable woes, interspersed with ad hominem attack on me and my career so, as Shel Silverstein so wisely said, "You're the winner." Bask in the glory of your victory

 

Thanks, it’s obvious that guys like Carl don’t get it and I shouldn’t waste my time responding to them.

Sometimes I just can’t help myself.
It’s not about making attacks or telling horror stories about workplace accidents or fatalities which unfortunately I witnessed 3 of during my time in the field.

It’s about trying to foster a deep and positive attitude towards safety that will follow the students through their lives on the job and elsewhere.

I’m presently teaching a 1st year apprenticeship welding class and I have a couple of students that are starting the trade at 18.

Sure the stories help to make a point, the best thing that can happen is that they get the message and determine for themselves that the best course of action is to use every bit of PPE they can on any job they do or even at home on the weekends.

And they have a long safe career.

I try to tell them not to listen to old guys who will say “Look at me, I’ve done it this way for years and I’m okay “.

Am I a little passionate about what I do?
Sure I am but I still enjoy helping and guiding our future tradesmen.

 

You weren't clever, you were lucky. Just toured the Mining Museum in Grants,NM while driving 66. They mined uranium in shirt sleeves. Fully professional miners. Want to guess how they're doing now? If one is training for a future job, you need to learn how to do the job according to current standards of safety. Is there such a things as too safe? Oh, and I hope you won't take offence, but offense is the commonly accepted spelling in the United States for any application of the term (Garner’s Modern American Usage). Offence is the spelling preferred when writing for a British audience (Fowler’s Dictionary of Modern English Usage). You could look it up.

 

I had to wear a hard hat to read the hamb today

 

Jeeze, I thought this was done, but it has taken on a life of its own. First of all, I never claimed to be "clever". Don't try to put words in my mouth. Secondly, we aren't talking about mining uranium, we're talking about cutting out a circle. Thirdly, we left British rule and their spelling peculiarities in 1776.
I have a simple request. Please, anyone, tell me, based on the video, what could have gone so dreadfully awry, that the torch wielder could have been injured. Do not invent scenarios such as, "What if there was a sudden solar eclipse" or "What if a velociraptor ran into the room". Base your reply on exactly what was shown and leave the fiction to the novelists.
I'm going to go and run with scissors

 

How many Safety Nazis have never, ever, got their hands dirty ?

 

Make a circle cutter, based on photos of commercial circle cutters.
Set the radius larger, to do some test cuts.