Cone Rolling

[Vaulter]

I am building a new smaller Lockwood and I am having troubles with my new facilities. I am rolling the tail pipe in two 21 inch sections. The roller has two rolls that feed the material onto the third roller. I can not seem to get the steel to follow the proper radius. I have tried tightening one side of the roller with limited success. Does anyone have any suggestions? Thanks.

[kid jansen]

I built mine by hand, all parts, and the exhaust in one piece.

[Eric]

A few of the people I have been selling plans to have been making dual engines of a smaller size which makes rolling the big cones easier :)

If you dont have a really good slip roll getting it to actually slip for cone rolling can be nearly impossible. Most of the cheap 3 in 1 units are only good for rolling straight tube sections.

It is possible to roll the cone by hand more or less, if you have a good thick pair of welding gloves you can really work the metal quite nicely. If you work it by hand as much as possible and use a rubber mallet to get closer to the desired shape you can then close the gap with exhaust clamps, and mallet it some more you can get a pretty good cone.

In the end there really isnt any substitute for a good roller.


Eric

[Jonny69]

I did mine on the rollers and just tightened one end more than the other. The long cone I made needed a lot of pulling and muscle work and a good thick pair of welding gloves so I could get a good grip.

[kid jansen]

A few of the people I have been selling plans to have been making dual engines of a smaller size which makes rolling the big cones easier :)

I disagree with that, I think the large cones on my lockwood (except for the exhaust) were way easier to make it in to shape than those small ones.

It is possible to roll the cone by hand more or less, if you have a good thick pair of welding gloves you can really work the metal quite nicely. If you work it by hand as much as possible and use a rubber mallet to get closer to the desired shape you can then close the gap with exhaust clamps, and mallet it some more you can get a pretty good cone.

And that's exactly the way I did it, except that I also used those diamond core drills for wet drilling in concrete. They are pretty strong and a good way to get those cones nice into shape.

[Eric]

Well making two smaller engines can make things easier. Most slip rolls that people have are 30" wide, and the big cone would normally need to be rolled in several pieces or on someone elses machine. Also when you go with a smaller engine you can use thinner material which does make a huge difference. If you try to make the smaller engine from the same thickness material you will have problems rolling it.

Eric

[Bob]

I think Johney69 said it best... do it slowly by hand in the rollers and MAKE it slip a little at a time, no doubt it will be off a bit but you should be able to get it close enough to weld up nicely.

if your Rollers are powered that would be dangerous to do and might cost you a finger or two I am thinking of a hand crank set of rollers like ya get at harbor freight ! ( been thinking about buying one <grin>)
...
I might also sujest you make a few trys with a piece of flashing or something cheep like good o'l tin before ya bend up the Stainless steel if you get to eyeball the angle once that comes out right you'll have an easier time of it with the real thing !
....

my 2 coppers worth !
Bob.......

[hinote]

I think Johney69 said it best... do it slowly by hand in the rollers and MAKE it slip a little at a time, no doubt it will be off a bit but you should be able to get it close enough to weld up nicely.

Look at:

http://www.pulse-jets.com/phpbb2/viewtopic.php?t=1776&

Also:

http://www.pulse-jets.com/phpbb2/viewtopic.php?t=1178&

[Eric]

I really really really wouldnt buy the 3:1 machine from harbor freight, they are extremely cheap, never work correctly, and the slip roll is the only thing that even comes close to being useful, though only for straight tubes, its virtually impossible to roll cones.

The brake is also a joke, and the shears flat out dont work like they are supposed to no matter how much you adjust them, and if you do manage to get it to cut more than a 4" wide strip it takes about 250 pounds force with the lever fully extended in order for it to cut.

If you go to the harbor freight store you can see the "quality" of the machine. The enco machines are not much better.

Every good slip roll I have ever used is about 50 years old. They definately dont make them like they used to.

Eric

[Dang911]

To quickly jump in here. I rolled my 43" yes 43" exhaust cone, all in one shot. I did it on a 50" slip, and it gave me my daily gym workout. In rolling the smaller cones, I would turn the material as I fed it through, which made a perfect cone. BUT with 43" of material, it was impossible to turn the material. So this is what I did. I rolled it linear, until the narrowest part of the cone just lapped. The wide part of the cone at this point was way overlapped. After that, with 2 strong guys, I just pulled the one end of the material to meet flush with the other end, this fixing the incorrect bend. With a quick tack at both ends and the middle, it was done. Rolled linearly, but repositioned perfectly. And this was with 1mm 321 stainless. A safety note: wear cloves when pushing sheet metal with such force.

Hope that helps....

[Eric]

Yea a lot of times there are sizes that you just cant roll with the slip roll when the sizes are too small for the roller diameter or the difference in diameters is just too great and it wont slip.

I have quite a few odd sizes that I end up forming by hand, after a while you just get really strong forearms and things become pretty easy. If I made any more pulsejets my arms would be like Popeye's.

I always use thick welding gloves because one slip on a sharp corner could cut your arm down to the bone or take a finger right off if you are trying to force things together with 100 pounds force. I have a pair that go all the way up past my elbows with really nice thick leather that I usually use with sheet metal .

I have been interested in those stainless steel chainmail butchers gauntlets, but I have a feeling that they wouldnt work very well for welding :D

Eric

[Vaulter]

Thanks for revisiting the ancient art of cone rolling. I was finally successful in rolling my cones with a simple tube roller. One of my biggest problems is that I am using thick stainless steel (about .060"). I am pretty sure this is overkill, but it is what I had. I found the hard way that the more you cold work SS the harder it gets. On the exhaust I used three large hose clamps and a couple of jars of elbow grease to get the ends to match. All this work resulted in an oval shaped cone. This was nothing my gravitationally accelerated pendulum adjuster (hammer) couldn't fix. My cones are now much nicer than first Lockwood destined to be a one minute wonder. I will post some picture when I finish the construction.

[Mike Everman]

"gravitationally accelerated pendulum adjuster" ha

[Knight]

(First post ever). Just finished making my Chinese prototype from plans on the site (I was a third year apprentice machinist at one time before my career change) I never took any sheet metal classes, but have the math skills to draw out all plans on flat sheet, lacking stainless steel 0.013", I used large coffee tins flattened out and then rolled my tubes and cones by hand using a 1" diameter pipe and then rivetted all together and sealed with muffler cement. Ugly, but functional, I'll try to post a picture sometime.

My $0.02 - roll by hand, I found that it wasn't that hard and it has been 15 years since I worked in a fabrication shop. And hey, if you need some practice, keep your coffee tins and flatten them out, draw, cut and practice rolling.

Thanks

[kid jansen]

Yea a lot of times there are sizes that you just cant roll with the slip roll when the sizes are too small for the roller diameter or the difference in diameters is just too great and it wont slip.

I have quite a few odd sizes that I end up forming by hand, after a while you just get really strong forearms and things become pretty easy. If I made any more pulsejets my arms would be like Popeye's.

I always use thick welding gloves because one slip on a sharp corner could cut your arm down to the bone or take a finger right off if you are trying to force things together with 100 pounds force. I have a pair that go all the way up past my elbows with really nice thick leather that I usually use with sheet metal .

I have been interested in those stainless steel chainmail butchers gauntlets, but I have a feeling that they wouldnt work very well for welding :D

Eric

Gloves are pretty usefull indeed, especially when you're not just pushing but hanging on it with full weight, that's 200lbs on that sharp edge in my case. But it worked pretty fine, and I made that cone in only 2 hours with just doing that.