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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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How to make tapered tubes?
"steamer" wrote in message
... --A friend of mine wants to build some big-ass Hero's turbines. He wants to have the steam exiting from tapered tubes on either side of the devices. What we need is a method to roll, or otherwise form oh, say, 18 or 20 ga. steel into tapered tubes; maybe 12" long with 1" dia on the small end and 2 to 3" on the other end. So how is this normally done; i.e. do we need to make a mandrel or some conic sections to drop into a custom roll former, or what? --TIA, It's done with a slip roll (roll former). I haven't done this since high school shop, so you may want to get some advice that's more up-to-date. g There are two ways to do it. You can set the back roll at an angle, if your slip roller is made for it; or you can "drag" one end of the work through the rollers, so that the wide end is moving faster through the rolls. In my high school shop class we had to do it both ways. I never really got the hang of dragging the work, but I think it's a matter of practice. Any good HVAC or sheet-metal shop should be able to do it for you, pretty cheaply. Ed Huntress |
#3
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How to make tapered tubes?
"Bruce Simpson" wrote in message
... On Fri, 08 Aug 2003 17:54:45 GMT, "Ed Huntress" wrote: It's done with a slip roll (roll former). I haven't done this since high school shop, so you may want to get some advice that's more up-to-date. g There are two ways to do it. You can set the back roll at an angle, if your slip roller is made for it; or you can "drag" one end of the work through the rollers, so that the wide end is moving faster through the rolls. In my high school shop class we had to do it both ways. I never really got the hang of dragging the work, but I think it's a matter of practice. Any good HVAC or sheet-metal shop should be able to do it for you, pretty cheaply. The problem is going to be the 1 inch end -- the smallest regular slip rolls I've seen have rollers about 2" in diameter. If the rollers are too thin then they bend in the middle and everything you roll ends up having a tighter radius at the ends than it does in the middle. This job might require some judicious use of hand forming to get the small end formed. You'd be surprised what can be done with a steel dolly (a piece of 1" diameter steel rod in this case) and a well swung hammer :-) -- you can contact me via http://aardvark.co.nz/contact/ Oh, yeah, that's pretty small. I've seen small slip rolls, but I don't know if they would handle 1 inch directly. If you can get close, you usually can pull the form around to the final shape. 22 gage is quite thin. Ed Huntress |
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How to make tapered tubes?
On Fri, 08 Aug 2003 21:55:36 GMT, "Ed Huntress"
wrote: Oh, yeah, that's pretty small. I've seen small slip rolls, but I don't know if they would handle 1 inch directly. If you can get close, you usually can pull the form around to the final shape. 22 gage is quite thin. Yep, hoseclamps or even some clever rope-work will likely pull the seams into line then you can weld and bash it into something resembling a round tube. I use the hose clamp trick all the time to hold thin stainless tubes before I tack along the seam. Then I clamp the bits between a couple of chill-bars and take my TIG to the seam. The results usually work out pretty good. -- you can contact me via http://aardvark.co.nz/contact/ |
#5
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How to make tapered tubes?
I have always wanted a 'magic' way to make small diameter tapered
tubes. Having looked the past couple of years for a simple solution, I have kind of given up. A local blacksmith/artist acquaintance does it by taking pipe or tubing, he then cuts a wedge shaped piece out of the pipe, from one end to the other. Next he heats the pipe/tubing up in his forge and the proceeds to 'close' the pipe/tube back together using various forms he has made as an aid/support to his hammering. Then he welds the edges back together. Once formed he the proceeds to shape the tubing into the form of tree branches or vines. Very laborious process, but it looks beautiful. I was thinking that a hydraulic press might aid in the closure of the pipe, but haven't tried it myself. Still searching for an easier way. rick |
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How to make tapered tubes?
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#7
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How to make tapered tubes?
wsolurb ( Doug Goncz ) wrote in message ...
From: Trevor Jones There are machines used to swage the tapers into chair and table legs. You can make ONE metal part the hard way over a form, and braze it. Make it niiiiice inside. Then put it in a tall container and fill all round with concrete or mortar. Then you can roll your blanks up on a regular sheet roller, press them into the "mold" and tack inside in two places with a stick welder. Then, if you braze, file, and polish the outside, they'll look slick. Stainless can be matched with the righ braze filler. Another way to do it is to have a resilient base matched to the weight of a large flat bottomed object which presses a tapered form into the sheet. With the right distribution of weight and "give", you can roll the taper. You'll have to deal with sprindback, but that's super easy: just make the small end of the form a little long... Something like a Vlier pad (several layers of inner tube butyl rubber from the junkyard) is cheap and adjustable. The weight can be something like an anvil. Yours, Doug Goncz, Replikon Research, Seven Corners, VA Unequal distribution of apoptotic factors regulates embryonic neuronal stem cell proliferation I saw a method when I was in Jr High school. It is called explosive forming. I don't have an idea of how big these tubes are but this is how I would try it. Machine a long bar with the taper inside of it. Mybe you might split a solid bar first . Then thread the outside of it and put nuts on the outside. Then machine the tapper inside . next on the big small end make a manderal that will fit inside of the tube your are going to taper. On the big end of the tube make another manderal that fits on the Id of the tube. Put silicon sealer on the manderal and the tube to make it water tight. The tube is going to fit tight on the od on the small tapered end and fit loose on the big taperd end. On the big tapered end of the manderal drill the manderal to fit in a 45 cal blank shell. then screw in a bolt about 4 times diamiter deep. Drill a hole for a firing pin to strike the percussion cap on the 45 blank. Get a wait to drop form a pulley and take the end of the cord and supend over the firing pin. Get back behind somthing big and let her drop.It should work. Make sure that the firing pin has a bigger dia than the hole so it doesnot fire out of the bolt and act like a bullet. It might take two or three forming attempts. If your tubes are long you might have to take this set up out and put in blasing caps to form the tapered tubs but that is a high vilocity blast and it might crack the tube. give it a try and email me back how well it works. |
#8
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How to make tapered tubes?
The Hooker Super Comp ceramic coated headers did not fit the transmission
support humps in my GM A-body, so I had to make tapered offset collectors. Making the cones was easy. Get the right size tubing for the big end and then carefully mark and cut out the right size triangle from the wall of the tube, leaving a small section attached at the big end. Carefully work over the tube so the small ends come together. Tack weld the small end. Slide the cone over a mandrel -- in my case a section of 2" pipe -- and hammer the gap flat. Tack the center. Smooth over any other places that might need it, then weld up the cone. |
#9
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How to make tapered tubes?
Idea
Pool cue. Find appropriate diameters on the stick. Use material 1/3 thinner than your final part. Form and or spin the metal to fit the cue. Make a second piece. Same way but slightly larger (higher) on the cue. Slip them together. Sweat/braze/ weld. |
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