Angle Iron - welding to 90 degrees

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Great forum - first post - newb welder.I am going to be making a welding table and the legs are going to be made out of angle iron.  I was thinking of making the bottom frame by cutting a 45 degree angle on the 2 pieces of angle iron to make them meet and then welding together.  I was looking on the Miller website yesterday about making a stool and they said to cut a notch out of the angle iron the same as the width (step #2 and #3 at http://www.millerwelds.com/education...s/shop_stool/).  So this way you are getting 2 shorter 90 degree welds vs a long weld on 45 degrees.Is one better than the other for strength?Am I making any sense what I am asking?
Reply:The link doesn't quite work (the final ")" is included in the link, but I got to the page.I don't think that makes it any stronger.  I've always done the 45 degree cut like you were considering.  Never had anything fall apart that way...
Reply:I think you are making good sense.  You also have a good question.  The link for some reason doesnt work, but I think I understand what the basics are.  It would seem to me to be more an aesthetics than a strength issue for that type of application.  Once welded, the two pieces are one...that is, if the weld qualtiy is good.  I cant think of why one would be inherently stronger than another, since the angle's thickness or shape doesnt really differ between the two methods, unless you conisder the strength of the base metal relative to the strength of the filler.  Welds can be stronger than the surrounding base metal, and this might affect the actual strength of one type of joint verses the other.  I have to admit that I use the cut-out-tab method for 90 deg angles in L-stock, just because it's easier to get right with the tools I have.Maybe some other folks can fill in more detail here.Smithboy...if it ain't broke, you ain't tryin'.
Reply:AZkickI use the notch method.  I also think it is easiest to get right.  You also only have to touch one cut one piece of metal.  I also saw in old welding manual that this is the correct way to join angle.  Perhaps it is used because it was easiest to cut with a torch in the field.I always assumed the notch method was safer/stronger because the weld is not at the stress point.  With the notch method the weld goes around the stress point.  Don't know how much this would matter on a table top.     Legs...?How are you building this table?  I am inerested in knowing how you are attaching the legs.  www.metalwebnews.com there's info how to calculate and miter angle iron at a 90  degrees arc.  Porbably not what you need for this project, but neat info.There are table plans there also.
Reply:After reading tapwelder's comments, I think I agree with him about the strength.  With a mitered 90 deg angle, the welds are all in a straight line.  Any defect might more easily lead to failure of the entire weld in this configuration.  But, if the weld zig-zags, any directional stress would be different for different parts of the weld.  I don't think I am making much sense, but I am trying.  Maybe if you put your hands on the screen, you see what I am thinking.Smithboy...if it ain't broke, you ain't tryin'.
Reply:This problem needs finite element analysis.I honestly can't imagine that there's that much of a difference between the two.  I think it would depend on which axis were receiving the most load.  As long as the welds are good, then they should be stronger than the parent material (assuming ER70S-6 and A36).-Heath
Reply:I do it sometimes, for light duty stuff, I use a 45, but for heavyer duty stuff when I have 3 or 4 peices coming together, usually everything gets notched like a puzzle.Owner of Welding Wiki,The free wiki based resource for weldor's around the world.http://www.weldingwiki.comWe have cookies!
Reply:I usually do the 45 degree angle cuts, just because we have a horz bandsaw at work ( that has 30 degree and 45 degree pin stops) and it makes it easy, I have also used the " cut out tab" method where you just notch the L-Angle with a pneumatic cut of wheel or grinder (this in my opinion takes a little more time,) but as far as strength is concerned I would think they are about equal, so it boils down to the equip you have on hand
Reply:Well, in my simple mind, the notched method provides for more lineal distance of weld bead, therefore stronger. But, forget the things that roll out of my head, I've read numerous times from experienced welders that the notched method is stronger------so that's what I go by.  I would also imagine that if both welds were ideal the difference would be minimal for everything but the most critical of applications.
Reply:Thanks for all the input so far - it has been very helpful.I went to the garage tonite to play w/ my new Rigid Chop Saw and having a hard time cutting 45* angles with it (3" angle iron)I can cut 90* very well when I put the pointed end up but the problem comes in when I try to cut at 45*. The part of the angle iron that is sticking up cuts like butter but the problem comes when I try to cut the part that is parrallel w/ the base - the blade seems to just spin on it.  Any ideas how I can do this?I also tried to cut the "notch method", but need to get better at my measurements.  I cut the vertical piece w/ the chop saw easy enough and tried to do the the part that runs parrallel w/ the "v" w/ the chop saw as well by clamping it to the base of the chop sawbut didn't get it very close to make it a clean edge (about 1/8" gap).  I ran out of time and energy to grind it down.  Any tricks on doing the notch cuts?  Thanks!
Reply:I also tried to cut the "notch method", but need to get better at my measurements. I cut the vertical piece w/ the chop saw easy enough and tried to do the the part that runs parrallel w/ the "v" w/ the chop saw as well by clamping it to the base of the chop sawbut didn't get it very close to make it a clean edge (about 1/8" gap). I ran out of time and energy to grind it down. Any tricks on doing the notch cuts?
Reply:Sandy is right about those cut off blades.  I found a stack of 20 at the tractor supply company for about 6 bucks.  Their no-name brand blades arent the best quality, but they save time.  I have used a torch, a circular saw+metal blade, and a reciprocating saw.  Torch for thicker, R-saw for thinner, circular saw for stuff in between.  A while back, I made a pair of wall-mount desks for my office using old solid core doors and old steel bed rails.  I notched the bed rails with the circular saw.  I dont require a whole lot of precision, so most times I freehand stuff like this.  They have withstood my standing on them to change lights, and my sitting on them along with 2 big 19" monitors and gobs of other junk.  They are probably more likely to pull out of the wall than to break.Smithboy...if it ain't broke, you ain't tryin'.
Reply:I was hoping you all would tell me that I need to go out an buy a plasma cutter for a job like this.  Thanks for all the input everyone!
Reply:If I use a chop saw, then I will use the chop saw for entire operation.  If needed, I even grind with the chop saw. For parallel cut: since the chop saw blade will flex,  I turn the angle vee-up to keep the blade from straying.  For vertical: I rotate the corner of the angle up slightly in order to cut the vertical leg deep enough. Perhaps put a piece of scrap under the corner of the angle so you can cut deep into the corner.  I cut vertical first.I rarely use a chopsaw ("nasty nasty"...chop saw) anymore. I use a portable bandsaw, vertical bandsaw, angle grinder with cutting wheel or sometimes torch. Nasty nasty...chop saw- because of all the fine debris that flies around my shop and into my face. Also, the flexible blade causing untrue cuts.Last edited by tapwelder; 12-07-2005 at 10:06 AM.
Reply:Originally Posted by AZkick-n40I was hoping you all would tell me that I need to go out an buy a plasma cutter for a job like this.  Thanks for all the input everyone!
Reply:PAToyota,What kind of rig do you drive?  I see Toy in your name and you like to offroad in your profile.
Reply:PAToyota = Pennsylvania Toyota  Building a custom truck out of an '85 Toyota solid axle pickup.
Reply:The 40 in my title is for my '71 FJ40.  I also have a '78 FJ45 which has some rust that I need to get rid of - hence my desire to learn to weld and do bodywork.
Reply:The notch method is the most practical for larger angles than one inch.  If you do it correctly when building any rectangular frame all your cross members including your ends are identical in length.  Your cross members should be two thicknesses short and your long side rails should also be short two thicknesses.  This gives you an open corner joint on the outside for maximum penetration.    If you choose to cut 45 degrees at the corners cut your lengths two thickneses short then cut your 45's on the chop saw so that only the flat leg is cut.  This again will give you an open corner joint on the outside.    The "notch " method is actually a "cope".  Coped joints are used for all angles , channels, and wide flanged beams when doing structural.Last edited by lotechman; 12-08-2005 at 12:06 AM.
Reply:Lotechman,What do you mean by "two thicknesses short"?
Reply:Generally it means twice the thickness of the metal you are using.  So cut a piece that is "x" inches long minus twice the thickness of the stock for the overlap at either end.FJ45 - pickup?  I've always liked those!
Reply:So if I am using 1/4" thick metal then I cut it 1/2" short?  I'm not challenging the statement here but trying to understand.I can see that if a piece of metal is 16 gauge or smaller then it would work, but for the thicker stuff do I use the same rule-of-thumb?(PAToyota - yep the FJ45 is my dream truck and the reason I started welding.  It has some rust and I want to do the body work on it myself to get it back to original condition.)
Reply:Thanks for the explanation Lotech and PA.  It took both for me to understand.     AzKick, your calculation is correct and it would work for any gauge.What they are saying is if you are building a frame like a table top of set dimensions where there are cross members for support, then all a the cross members and end pieces can be cut the same length.  The minus 2 thicknesses allows you to get the cross member into the frame.  It compensate for the thickness of the angle you are tying together.  The minus 2 thicknesses on the end and long pieces is like putting to books at 90 degrees together where the inside corners touch.  With the inside corners touching then you can fill the outside with weld.Thanks guys
Reply:I have tried to deliver some bitmap files showing an angle cope but for some reason I can't get them much smaller that 259 K and that is too much for this site.  It seems anyway that the principal is understood.  Normally these copes can be done with a torch if you are neat and use a small tip size.
Reply:Originally Posted by tapwelderThe minus 2 thicknesses on the end and long pieces is like putting to books at 90 degrees together where the inside corners touch.  With the inside corners touching then you can fill the outside with weld.Thanks guysPaToyota is absolutely right.  Too many tools in Latin is roughly translated as "too small a shop."  The ancients were very wise people, you know.Smithboy...if it ain't broke, you ain't tryin'.
Reply:You lost me for a moment there...Then I went back through what I had said: http://weldingweb.com/showpost.php?p=30067&postcount=15
Reply:PaToyota is absolutely right. Too many tools in Latin is roughly translated as "too small a shop." The ancients were very wise people, you know.
Reply:I don't think you offended anyone.  I had made a comment on the last page that you can't have too many tools!
Reply:You can never have too many tools...  This is one point I have a great deal of difficulty getting across ot the rest of my family!   I have one of those Rigid chopsaws, and I noted with some disappointment, that the blade has great difficulty making its way through material any more than 1/4 inch in thickness when laid flat on the table.  Heavy walled square tubing is a nightmare.  I have been looking at those ferrous/ nonferrous 14 inch saws, and devising a way to make a new gearbox to bring the blade speed down on the abrasive cutoff saw so I can use one of the carbide blades.Whats a day without flippin' like a trout?