cutting end caps for pipe

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I will be building a grill out of some 20in. pipe. I need to cut out some circles for the end caps. Should I cut the end caps 1/8 in. smaller so it gives a gap that I can weld into. Also Im wanting to either build or buy a cutting guide to go on the torch to make the cut easier. What kind of compass do you use to make the circles.
Reply:whenever I cut square or round tube/pipe caps I always subtract 2x the wall thickness for a nice corner joint.Have we all gone mad?
Reply:So if it is 1/4 in pipe cut a 19.5 inch. circle
Reply:That will work. I cut mine where they will just sit on top of the pipe and then do a fillet weld, then grind it smooth. Your LWS will have a gadget called a circle marker.  It hold a piece of soapstone in one end and the other end is pointed to fit in a center punch mark. It's just a specialized compass. If you are fairly good with a torch you can just cut them out freehand. No need for a circle cutter. If I were cutting a dozen I would rig up the circle cutter. For two I would just slice them out freehand.
Reply:Originally Posted by lineman21So if it is 1/4 in pipe cut a 19.5 inch. circle
Reply:Lineman,Good advice regarding how to cut your end caps.Based on this and your other posts, I'd suggest (unless you are really good with a torch) that you torch cut your end caps at least 1/8" radius larger than the ID (inside diameter) of the 20" pipe you're using.  Then take a soapstone and mark the final diameter on the piece you've cut.  Use a hand grinder to get to your final dimension.  Will give you a tighter fit.Additionally, I'd recommend tack welding about three tabs (1"x1"x1/4") inside the pipe where you want the end cap postitioned.  These tabs will hold the end cap in position while you're tacking it in place in the pipe.  With these tabs, the pipe can be rotated to a vertical position, cap dropped in, and the whole thing welded "in position".Just a thought.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:A "circle burner" attachment for a hand torch would be great for cutting your end caps. I have attached an image of a circle burning attachment (Currently on Ebay $35.00) useful for an entire lifetime if care is taken.      For the dirt cheap circle marker   tie a string around a piece of soapstone  hold 1 end on the center of part & rotate 360 deg. Not extremely accurate but will get you close.I have also attached a image of how I would assemble the end cap to the pipe. Attached ImagesIF IT WORKS, DON'T FIX IT2 Lincoln CV-300 / LN-7 GMALinde-VI 253,400 & 450 w/MIG35 feedersCNC Table with Oxweld O/A & Hypertherm 1250G3Lincoln Ranger GXT 250Hobart-MicroWire 300ESAB Heliarc 161ESAB-Mobilemaster 2 CC/CV Feeders& more
Reply:http://cgi.ebay.com/Circle-cut-guide...3286.m20.l1116works well with the wheels on it
Reply:Originally Posted by OldtimerThat will work. I cut mine where they will just sit on top of the pipe and then do a fillet weld, then grind it smooth. Your LWS will have a gadget called a circle marker.  It hold a piece of soapstone in one end and the other end is pointed to fit in a center punch mark. It's just a specialized compass. If you are fairly good with a torch you can just cut them out freehand. No need for a circle cutter. If I were cutting a dozen I would rig up the circle cutter. For two I would just slice them out freehand.
Reply:FOUND A PICThe heat on the corners from the welding operation seems to a good job of penetrating both the tubing and the cap.  Shoulder/corner welds concentrate heat in a very small area.I'm pretty sure it wouldn't be adviseable in a pressure application, but for a cosmetic or non pressure application, it's been ok for me Attached Images"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by farmersammFOUND A PICThe heat on the corners from the welding operation seems to a good job of penetrating both the tubing and the cap.  Shoulder/corner welds concentrate heat in a very small area.I'm pretty sure it wouldn't be adviseable in a pressure application, but for a cosmetic or non pressure application, it's been ok for me
Reply:Here is something that I use all the time when I cut circles. You can use anything with a point. Even a sharpened rod that has a bent angle on it. And just clamp it to the torch. If I did it more circle cutting, I would make some kind of an adjustable tool designed to clamp onto the torch.        Sincerely,             William McCormick
Reply:I end up having to freehand alot of access holes in half assembled P&H equipment at work,They are square holes with 3" radius corners. I lay out the hole with soap stone then put center punch marks on my line every 1/2". I have a hard time seeing the soapstone through a shade 5 lens. So you just connect the dots and it turns out pretty good. My .02Yup
Reply:Hello lineman21, here's an example of a circle burner that I fabricated some time ago. I use it by itself or with a rotary burn table depending upon the application. Attached Imagesaevald
Reply:Originally Posted by BurnitI end up having to freehand alot of access holes in half assembled P&H equipment at work,They are square holes with 3" radius corners. I lay out the hole with soap stone then put center punch marks on my line every 1/2". I have a hard time seeing the soapstone through a shade 5 lens. So you just connect the dots and it turns out pretty good. My .02
Reply:And you better never never never start a fire with a green shade on.  You cannot see it.You smell it before you see it, and by then, it's azzholes and elbows tryin' to get to the water hose.  LMAO"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by farmersammAnd you better never never never start a fire with a green shade on.  You cannot see it.You smell it before you see it, and by then, it's azzholes and elbows tryin' to get to the water hose.  LMAO