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  • cut a circle

    What is the best way to cut a circle with an oxy acetylene torch free hand

  • #2
    Here is what I had made for cutting circles with my plasma.



    Since, I have changed the center point to a small magnet, and now with the magnet in the middle I don't have to have a retainer on the torch. I am leaving for a BBQ contest in the AM, but If you would like a pic of the new set-up I can take a pic Sunday when I get home.

    I would think that you could adapt this for the O/A torch as well. The magnet was 3 bucks and I had the set screw collars and round stock, so for me it was very cost effective VS the 100 plus dollars for the store bought.
    Stickmate LX 235 AC / 160 DC.
    MM211 AS and Spool-Mate 100.
    Spectrum 375 X-Treme.
    O/A Medium Radnor Torch, Large Victor Torch.
    Milwaukee 14" Chop Saw.
    4 x 6 Horizontal Band Saw.
    Rockworth 80 Gallon 2 Stage 16 SCFM @ 175 PSI , 15 SCFM @ 90 PSI.
    Jackson Passive Shade #5 for the plasma.
    I almost forgot the Hobart XVP AD Hood.
    Speedglas 9100x


    Projects and Misc Albums
    http://picasaweb.google.com/keesfriend Feel Free to Have a Look ( Just keep in mind I am an amateur )

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    • #3
      This was under $10.00 (seems like it was about $6.00) a few years back from Harbor Freight. Its actually pretty well constructed. You could make one, or buy a similar one at your LWS (would be about $60.00 or so). Check ebay.



      You don't say how large a circle, or how thick the steel, both can make a big difference. I have free- handed plenty of them, following a soapstone line I traced around a paint can, soup can, etc.
      "Good Enough Never Is"

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      • #4
        he said freehand,,, years of practice.
        http://www.facebook.com/cary.urka.urkafarms

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        • #5
          Get some lessons from this guy. (go to about 1 minute in if you are in a hurry.)

          http://www.youtube.com/watch?v=eAhfZUZiwSE
          --- RJL ----------------------------------------------

          Ordinarily I'm insane, but I have lucid moments when I'm merely stupid.
          -------------------------

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          • #6
            I have to right a paper on what is the best way to cut a circles free hand and I have know idea except to just draw a bunch of circle for practice and just hope for the best. the circle are about 2inch and in half inch metal

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            • #7
              IMHO, the best way is CNC, but that isn't exactly freehand - at all! Not completely freehand, but I use a piece of pipe cut off 1.5" to rest the torch tip retaining nut on. I still draw a line because this puts the tip ~0.25" away from the guide. But it makes it a lot easier to follow the line when that is all you have to focus on. It seems to take a lot of attention for me to maintain a constant height.

              Dave
              Still building my new old truck - see the progress!
              http://www.ford-trucks.com/forums/65...-coe-idea.html
              http://www.hobartwelders.com/weldtal...ad.php?t=27017

              Square Wave TIG 200 - Woot!
              MM180
              SP125+

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              • #8
                Originally posted by StuntmanJosh View Post
                I have to right a paper on what is the best way to cut a circles free hand and I have know idea except to just draw a bunch of circle for practice and just hope for the best. the circle are about 2inch and in half inch metal
                Inside or outside circle? What are you looking for, a 2" finished circle of metal or a 2" hole? If its a hole, start off by punching a hole with the oxy/acet in the middle of the planned hole and work out from there until you get the right size...hard to put metal back on once its gone.

                Also, its considered bad form to ask others to do your legwork for you on schoolwork.
                Miller 251, Lincoln PrecisionTig 275, Miller DialArc 250 AC/DC, Hypertherm 900, Bridgeport J-head, Jet 14" lathe, South Bend 9" lathe, Hossfeld bender with a collection of dies driving me to the poorhouse, Logan shaper, Ellis 3000 bandsaw, Royersford drill press and a Victor Journeyman O/A.

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                • #9
                  Originally posted by Wyoming View Post
                  ...hard to put metal back on once its gone.
                  You bite your tongue! This is a welding forum, after all.

                  Dave
                  Still building my new old truck - see the progress!
                  http://www.ford-trucks.com/forums/65...-coe-idea.html
                  http://www.hobartwelders.com/weldtal...ad.php?t=27017

                  Square Wave TIG 200 - Woot!
                  MM180
                  SP125+

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                  • #10
                    Originally posted by whateg0 View Post
                    You bite your tongue! This is a welding forum, after all.

                    Dave
                    You're thinking like a carpenter...it all covers in the finish work.
                    Last edited by Wyoming; 09-25-2009, 01:47 PM.
                    Miller 251, Lincoln PrecisionTig 275, Miller DialArc 250 AC/DC, Hypertherm 900, Bridgeport J-head, Jet 14" lathe, South Bend 9" lathe, Hossfeld bender with a collection of dies driving me to the poorhouse, Logan shaper, Ellis 3000 bandsaw, Royersford drill press and a Victor Journeyman O/A.

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                    • #11
                      Originally posted by StuntmanJosh View Post
                      I have to right a paper on what is the best way to cut a circles free hand and I have know idea
                      Well, I "no" that you'll get it "write."
                      Trailblazer 302 * Millermatic 212 * Syncrowave 180SD * X-Treme 12VS Feeder * Spoolmate 3035
                      Thermal Dynamics Cutmaster 52 Plasma * Lincoln 175 MIG

                      Victor Superrange II * Victor Journeyman

                      Hobart HH 125EZ


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                      • #12
                        It has to fit a bearing in it without it going through. are there any techniques that any of you use to cut free hand circles.


                        Also, its considered bad form to ask others to do your legwork for you on schoolwork.
                        I wouldn't have asked if I knew what to write

                        Well, I "no" that you'll get it "write."
                        hahaha

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                        • #13
                          Originally posted by StuntmanJosh View Post
                          ...are there any techniques that any of you use to cut free hand circles...
                          What do you mean? Templates/guides and cutting jigs have been suggested. Do you mean completely freehand where your hand is the only thing touching the torch? If so, then a steady hand, the right sized tip, the right pressures, and practice.

                          Dave
                          Still building my new old truck - see the progress!
                          http://www.ford-trucks.com/forums/65...-coe-idea.html
                          http://www.hobartwelders.com/weldtal...ad.php?t=27017

                          Square Wave TIG 200 - Woot!
                          MM180
                          SP125+

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                          • #14
                            If you can rotate the metal, you could try this:

                            http://www.metacafe.com/watch/167195...ehand_circles/
                            Lincoln 175HD
                            Miller Thunderbolt AC/DC
                            Smith AW1, Dillon (Henrob) Mark III & Smith Quickbraze Little Torch

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                            • #15
                              yes completely freehand

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