Question about beveling pipe on a my lathe ( the angle)

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I have been using my lathe to bevel pipe/tube test coupons. The sections very from 2'' -6.5" diameter pieces and different wall thicknesses... from xxh, xh, 1/4"- 3/8"-!/2" wall pipe/tube.  I have my compound slide set at the angle to create a 37.5 degree bevel on the pipe/tube. I don't really know for sure the actual C/S angle is because there no #'s in the area. The problem is that even though my sections have 37.5 degree bevel angle, the included bevel seems way too wide. For example 1/4'' wall would have close to an inch wide bevel at the outer diameter between the two sections. When I see pictures (online etc) off tubing/pipe relatively the same diameter and wall thickness the included gap is much smaller. Maybe 1/2'' wide on the outside diameter. I am basically doing much wider "cap" passes than I think should be... Any idea's about what i am doing wrong??Lincoln pro mig 180Lincoln Square Wave Tig 300/wp 20/home built water cooler Victor, Purox, Harris, O/A welding/cutting setupsVintage Craftsman drill pressVintage Craftsman/Atlas 12"x 36'' lathe7''x 12'' w/c band saw Everlast 140 st
Reply:the 37 deg angle is off of square, or in other words, off of 90 deg. Your compound will read 53 deg. The 1/2 deg doesn't matter much.
Reply:See that's what is confusing me... the pipe/tube itself  is showing a 37 degree bevel, if I change the C/S angle it's going to change the bevel angle... how much tolerance is there in the actual bevel angle??Lincoln pro mig 180Lincoln Square Wave Tig 300/wp 20/home built water cooler Victor, Purox, Harris, O/A welding/cutting setupsVintage Craftsman drill pressVintage Craftsman/Atlas 12"x 36'' lathe7''x 12'' w/c band saw Everlast 140 st
Reply:i'm just grasping here but Is it possible your measuring the cut pipe bevel incorrectly, http://www.rjsales.com/products/ansi...es/misc/m.htmlWhen i cut bevels in a lathe i would rotate the work in reverse and cut on the back side of the pipe with the compound set a 37 deg.Briggs weldnpower 225/210/cvLn-25 suitcaseMillermatic 130
Reply:I think I am... I rest the straight edge,ruler part of my protractor against the inside of the pipe/tube and angle shows 37-38 degrees...tried my two different protractors as well...Lincoln pro mig 180Lincoln Square Wave Tig 300/wp 20/home built water cooler Victor, Purox, Harris, O/A welding/cutting setupsVintage Craftsman drill pressVintage Craftsman/Atlas 12"x 36'' lathe7''x 12'' w/c band saw Everlast 140 st
Reply:Same concept as I mentioned. When reading the pipe angle off of the axis of the pipe it will be 53 deg. To measure 37 deg, you want your straight edge across the cut end of the pipe. If I remember right, you have a good 2 deg tolerance. And for practice coupons the tolerance is whatever you're comfortable with. If you can weld it with a 30 deg bevel, you can do it with a 37.
Reply:Originally Posted by DemonSpeederI think I am... I rest the straight edge,ruler part of my protractor against the inside of the pipe/tube and angle shows 37-38 degrees...tried my two different protractors as well...
Reply:Ok... 1st pic shows how I measure the bevel, second shows the same bevel..either way it shows the same bevel measurement..37.5.... 3rd shows the difference..protractor angle is set at 52 degrees...I am going to reposition my C/S on my lathe to get a 52 degree angle... Attached ImagesLast edited by DemonSpeeder; 03-05-2013 at 10:13 AM.Lincoln pro mig 180Lincoln Square Wave Tig 300/wp 20/home built water cooler Victor, Purox, Harris, O/A welding/cutting setupsVintage Craftsman drill pressVintage Craftsman/Atlas 12"x 36'' lathe7''x 12'' w/c band saw Everlast 140 st
Reply:Soooo..I spun the C/S around (knob towards headstock) set it to cut a 52 degree bevel with the protractor and ironically the now C/S is showing that it's set at 37-38 degrees.... here are some pics... same piece of tube used as above pics...the included bevel gap is now a 1/2" ... before it was close to 3/4"... Attached ImagesLincoln pro mig 180Lincoln Square Wave Tig 300/wp 20/home built water cooler Victor, Purox, Harris, O/A welding/cutting setupsVintage Craftsman drill pressVintage Craftsman/Atlas 12"x 36'' lathe7''x 12'' w/c band saw Everlast 140 st
Reply:90° – 52.5° = 37.5°
Reply:I understand it now... Thanks for the help guys..Lincoln pro mig 180Lincoln Square Wave Tig 300/wp 20/home built water cooler Victor, Purox, Harris, O/A welding/cutting setupsVintage Craftsman drill pressVintage Craftsman/Atlas 12"x 36'' lathe7''x 12'' w/c band saw Everlast 140 st