Finishing an edge after a cut

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A friend of mine wants a headache rack like I have on my truck, and making the rack isn't proving to be a huge problem.  The issue is the bed rails are tapered, and he wants full length rail caps down his 8 foot bed; my rails are cut just long enough for a toolbox to sit on.My truck:Now imagine a tapering cut on the outside edge to match the taper of the bed rail caps.I figure (roughly by eyeballing it) 1.5x4" angle iron for the rail caps, then mark the taper using a marker, and cut it with OA (that's all we have).  After we cut it, how do we finish the cut edge so that it doesn't look like it was chopped down?  I've tried using a small angle grinder to finish edges before, and they never come out rounded evenly down the length of the cut, they always turn out trapezoidal with sharp edges.  And this is 16' total of edging that I'd like to make as uniform as possible.Is there a die grinder bit that makes pretty, mill-like edges?  Or do I need to practice with an angle grinder a whole lot?  Any recommendations about rounding off long edges?Last edited by texastech_diesel; 01-23-2011 at 05:22 PM.
Reply:Howdy Neighbor, welcome to the forum. - Hunted a couple years around SmyerFor a 'rounded' edge on plate etc. we occasionally cheat and use a belt sander.
Reply:They make special carbide circular saw blades that are designed to cut steel. I've used them a few times in a wormdrive. They also make the abrasive blades that will work also, but wear down fast and are messy. I'd clamp or screw the angle to some 2x's or saw horses and then cut the rough taper with a guide, and the finish the edges and cut marks with a grinder or sanding disk.I've got a friend who's a genious with a torch and could do the cuts that way, but my torch cuts, even using a straight edge are hit and mis some times..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Moving quick with a flap disk seems to produce an edge where you can't pick out a definite line. Hit the high spots with the grinder 1st then run along the edge with a 60 or 80 grit flap disk. That will give a smoother edge without the radical grinder marks."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:I agree with Sandy. Flap disks are the way to go for a smooth edge. I would recomend getting a 7" angle grinder an flap disks If you can but your small one will work as well. And it looks like I'm your neighbor in a roundabout way, I'm in New Home. Good luck on your project!
Reply:Is there any way to convince him just to use a uniform 3 inch piece so you won't have to grind it down? If he is dead seat on it then A 40 grit flap wheel is the way to go then a 80 grit to finish it off. Make sure you have a very streight guide and a steady hand when doing the cutting and you probably can get away with a few minutes of grinding. I just used 2 by 2 angle on my head ache rach I didn't want it to be close to the edge and catch shirts and a other stuff.Vantage 300 kubota ,miller 304 xmt ,lincoln ln 25 pro , ranger 305 G, plenty of other tools of the trade to make the sparks fly.
Reply:Originally Posted by tackitWhat's a headache rack?  Ladder rack? I would buy a good 12" mill file file and just take the corners off,   close enough to round and way more controllable than a grinder ..
Reply:Thanks for all the responses.  I think I'll try using flap discs after the cut on the test pieces, if that doesn't work I'll try some of the other ideas, like changing the cutting method.  Odds are the amount of cutting might have just went up a lot, we might also be cutting the vertical flange of the caps.  My first attempt at my local metal distributor looked like they don't carry any angle iron with a 4" flange other than 4x4 and 4x3.  I'm using that to try to convince the other guy to use short caps like on mine, but he's being a PITA about this.  Next step after rails is figuring out how to notch and bend the main outer frame, we'll see how that goes.Here's a better shot of what we're hoping to end up with:This is very much an on-the-fly, no plans, make-it-look-like-this-rack-I-saw-at-Wal-Mart weekend project, so we'll see how it turns out.
Reply:The ones I build for our trucks at work have  4"x3" x1/4" angle for bed rails and I just taper the last 12 to 14 inches with a torch, rough grind it and hit it with a flap wheel or die grinder with a roloc disc. The Ford beds are a little narrower at the rear than the front when measuring inside as well. If you have a piece of 3"x3" angle, it works perfect for the front to go across the bed. I will post some pics tommorow of one..............................."Look Good Doing It"!!!!!!!!!!!!!!!
Reply:Those are both good looking builds, although that second one is kinda dark...I picked up a couple of of these in DFW a while back  - if you're ever down Abilene way I'llgladly tack one on for ya...Make it SHINE.            Attached Images
Reply:Coyote, thanks for the spec tips and thanks in advance for the pics if you can find any, we're really eyeballing this project on the design side and trying to come up with ideas we think will be fun to try to make.  Originally Posted by SRO1911Make it SHINE.
Reply:4.5" cutting disc on a small grinder and a 7 inch flapper or paper disc.If you need a guide for the cutting disc....Try flexing a 1'x1'x1/16 angle (even try some thin wood) of the same length. It you can flex it close to this radius.......tack it down to the piece your cutting and flex it. Since these tacks will be on the inside of the angle, don't worry about base metal undercut.Do the rough cutting on both sides (rails) first, clamp them together and flapper/paper disc it.I would rather be doing it than typing about it!