- Thread starter ukracer
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brightspark
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depends on who made it . probably swaged if mass produced
Spark plug
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So if it was swagged would it have started life a a pice of pipe the same as the large diameter and be drawn down?
normspanners
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Opposite I would say
In a commercial environment I guess it would pay but I might be a few expanders from 3 inch to 4 inch BUT I am using some fairly thick walled pipe as I can get it locally with the shipping expense. If I was to make the correct cone out of some 18th steel I reckon I could bend it to form the cone and weld it between the 3 and 4 inch pipe. I had thought of buying them in but at £29 a pop its a waste of money..time is free money is not!
Spark plug
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Once you make a template to mark the material from it won't take long to make. Was there not a thread about this a wile back that had a link to a program that created a printable profile for cones?
Maker
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It may be 2015 but there's no need to be so modern, I'll stick with Radial line development thank you
To make the part in the first post, could you make a former for a fly press and flare it out from a piece of thin tubing, the same diameter as the smaller half.
Yeah it was mine...lol But that was to produce a 90 degree elbow. I borrowed a large bandsaw for that task in the end and god was it so much easier than a grinder and disc.
Especially as I have to justify my new plasma cutter..
Well the gauge I am using is way OTT but I am trying a theory on quality over quantity. I think the wall of the pipe is approx 4mm and the OD is 75mm. heavy duty for a flue pipe. BUT a number of people are asking for it to fit commercial flue pipe dual wall/thin wall etc etc. So I was looking at creating my own reducer.
I went to a warehouse yesterday and saw some thin walled flue pipe 4 inch diameter, 90 degree bends ,and 10 inch straights /liners for 19.99 plus VAT so I know I am undercharging but the reason for me making stuff is largely to keep my brain active as i have to care for my wife much of the time and its hard work, as long as I dont loose money I would have to be happy but it would make life easier if I can make a few quid.
normspanners
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If you had a lathe you could make a mandrel the shape you want to fit the large id of the pipe, place the pipe in the chuck with the mandrel inside, fabricate a rounded outer dia bearing ( like a self aligning plumber block) to be held by the inner race, in the tool post, warm the pipe and reduce it down by pushing the bearing against pipe whilst spinning it, it will stretch the pipe out longitudinally whilst reducing the diameter down to the dia and shape of the mandrel.
A mate uses this method for forming the end of 3-4" ish long stainless top cups for springs, for morgan 3wheelers out of straight stainless pipe, he forms it down through 90* and is left with a small hole in the base of the cup, that is drilled out to suit the king pin.
the spring then fits inside the cup, when polished you could not tell they are formed out of straight pipe it takes seconds to form and a couple of minutes to polish to mirror finish he make one to slide inside the other with clearance then the springs cannot be seen.
It is called metal or pipe spinning forming i think
A mate uses this method for forming the end of 3-4" ish long stainless top cups for springs, for morgan 3wheelers out of straight stainless pipe, he forms it down through 90* and is left with a small hole in the base of the cup, that is drilled out to suit the king pin.
the spring then fits inside the cup, when polished you could not tell they are formed out of straight pipe it takes seconds to form and a couple of minutes to polish to mirror finish he make one to slide inside the other with clearance then the springs cannot be seen.
It is called metal or pipe spinning forming i think
I have got a lathe mate...a great big buggar. Colchester master 2500. lol
NOW...to try and understand your message.
MattF
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NOW...to try and understand your message.
Make a form to mount in the chuck, of the size and shape you want the finished object to be. Slip the piece of tube over the form. Then you have a tool like a knurler in the toolpost but with a plain bearing on there instead of a knurling wheel. Use that to press against the tube and draw it down to fit the form. That's how I interpreted it, anyhows.
normspanners
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if you see the speed they are formed at you will understand how quickly it can be done, as said my mate uses heat but he is turning it through 90* to form a square ended cup.
this is how my mate does this but forms it into a cup
normspanners
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PS my mate makes brass radiators the old way and has had a former made to spin the rounded rad head,once he forms /spins it out, he then cuts them in half and make two rads out of one form, the mandrel is 18 ins dia had to be hand turned and finished and cost £1200. this is what they look like https://www.google.co.uk/search?q=m...thread.php%3Ft%3D509142%26page%3D210;1280;976
