Screws/Augers a easy way?

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Hi, i'm looking at making a few auger baffled mufflers for some race cars.I have plate and sheet development which spits out a profile based on diameter pitch etc which is good but each profile needs welding to the next sanded out and then pulled/rolled out to the correct pitch. I was thinking there has to be a easier way maybe using a jig in a lathe (low speed)Has anyone seen these made any other way.i'm only talking about forming some 1"X1/8" stainless flat bar.Any suggestions?Check out our website to see what sort of stuff we dowww.adrenalinR.com
Reply:Hello Krum, I believe you will be better off using your program and welding and pulling out your auger shape from "donuts" with splits in them of the appropriate starting diameter. There are machines that can form as you say in a spiral configuration with a lathe type mechanism but they are a bit complex and generally either crimp the internal ID or press and stretch the OD as they feed onto a mandrel to make up their shapes. Others may have different thoughts. Best regards, Allan  I do have a geometric differential equation if you are interested, to figure out the "donuts", but it sounds as if you already have that covered, if not, I will find it when I get to work and post it on this thread.aevald
Reply:Hello again Krum, got to work and gained access to the differential equation that I mentioned. I will include it here along with some pictures of a mock-up spiral staircase w/handrail. These might not be of any benefit to you specifically, but if others have any interest it may give them a few ideas. Best regards, Allan Attached Images Attached FilesDIFFERENTIAL GEOMETRY TO DETERMINE HELICAL HANDRAIL AND AUGER FLIGHTS.doc (63.5 KB, 91 views)aevald
Reply:I was looking as some small augers today in the shop today. The are 2 inch in diameter with a 3/4" core.  The flat bar appears continuous. I'm guessing it was formed using a powered ring roller. Because the flat bar is bent the hard way it would have taken a fairly powerful roll to produce. It's likely the bar was rolled hot because the inside is wrinkled free despite the huge amount of shrink. Cutting circles, slitting, pressing, and welding would be the method for a few.
Reply:Hi for hire,Yes this is what i have seen to, i only have access to a large set of ercolini sectional rollers that would not roll such a tight curve.