Diagrams of coped joints

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Ok you will have to be patient with me...  This is a simple diagram of an angle cope.  There are two straight cuts with a torch.  One cut is straightforward because it is across one leg of the angle.  The other cut takes out the heel part of the angle until it meets the first cut.  The advantage????  When doing a frame your side members are cut square.  Your cross members are all cut identically, even the end ones.  You can slide your cross members and end cross members anywhere you want between your two longer side members. Attached Images
Reply:Ahhhh I see what your doing now.   Makes perfect sense.
Reply:Originally Posted by lotechmanOk you will have to be patient with me...  This is a simple diagram of an angle cope.  There are two straight cuts with a torch.  One cut is straightforward because it is across one leg of the angle.  The other cut takes out the heel part of the angle until it meets the first cut.  The advantage????  When doing a frame your side members are cut square.  Your cross members are all cut identically, even the end ones.  You can slide your cross members and end cross members anywhere you want between your two longer side members.
Reply:Here are some more diagrams. Attached Images
Reply:Originally Posted by lotechmanHere are some more diagrams.
Reply:With a Bridgeport???!!!!!  You remind me of a steel support table I saw built that had tube legs cut on the band saw then clamped together and machined even on a horizontal borring mill.  The concrete floor never saw such accuracy.  The maintenance machinists in this particular company had a real sweet thing going.   With a bit of care you can lay out to a 1/64th with a sharp soapstone.  You can flame cut by hand within a 32nd.   It takes practice but a man with a good hand on a torch can cut and fit a lot of material saving handling time to and from the saw.  Zero and Double zero are my friends.
Reply:Sweet dude.  I had to draw it out earlier today and basically made the same drawing.  this process for framing seems much more forgiving than the 45deg cut.  Now all i need is a Bridgeport .  I'll do a few with the torch tomorrow.  thanks for more invaluable info. Lotech. Tim
Reply:With a Bridgeport???!!!!! yes a bridgeport..to this day i never prepped a joint   ummmm errrr or a weld joint any other way.. ...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Some tips on cutting a cope with a torch:  Use a small tip and minimal preheat cones even if you have to wait a while to start a cut.   Layout your angle cope lines with a sliding carpenter's square or better yet a quality machinists square with a cast iron head.  After use by a welding shop it is no longer a machinist's square but the cast iron does not wear like the cheaper aluminum ones.   Put the square on the inside of the angle and slide the rule down until you have the inside leg length.  (dimension "D" on the diagram) Take that setting and mark that distance from the end of your square cut angle.  Draw a square line across the back of one leg.  That will be your first torch cut.      Set your square to the thickness of the angle.  On the heel of the angle draw a line along the length of the other leg of the angle close to the heel.  That is your second torch cut.    When cutting first set the angle with one leg down with the angle pointing away from you.  Start your cut at the toe and carry it across to the heel.  Cutting at the heel takes practice.  You want to cut across the heel at a speed that will slightly cut into the heel but not so slow that you start to cut into the other leg.   Turn the angle so the the cut leg is down and the uncut leg is on the flat.  You should see your heel line.  Start at the tip of the angle and pull the torch toward you cutting along that line taking out the heel but leaving the rest of the leg.  If you have done it right you will meet your previous heel cut and the scrap will fall away.  On large angle you will need to make a little snip at the tip to allow it to fit the inside radius of the heel on your other angle.   The whole idea of using the sliding square is there is not numbers to remember.  Also every batch of angle iron is slightly different.  Mill tolerances vary.  You can have two inch angle with a two and one eighth to a one and seven eighths leg length.
Reply:I used to use the chop saw for the entire process (doing angle).  Lock it on and do all necessary trimming.  With a few practice cuts you can determine where to cut.  Now, I use cutting wheels on angle grinder or band saw.  Occasionally a torch if it is set up.
Reply:Hmm I thought this was pretty normal practice for the construction of machine frames.     How else would you end up with square and true frames?       Even this may not be good enough for what ever machine you are building often, assembly pads on the frames are machined true after welding interestingly on a horizontal mill also.The concrete floor is nothing that is why leveling feet (screws) are put between the frame and the floor.    Accurately built frames are important when you have multiple identical machines to assemble.    Even more so if those machines come from diffferent builders. The reality is a well built machine frame saves time.    Massing all of your parts for demensioning on a mill saves even more timeThanksDave Originally Posted by lotechmanWith a Bridgeport???!!!!!  You remind me of a steel support table I saw built that had tube legs cut on the band saw then clamped together and machined even on a horizontal borring mill.  The concrete floor never saw such accuracy.
Reply:Originally Posted by wizard The reality is a well built machine frame saves time.    Massing all of your parts for demensioning on a mill saves even more timeThanksDave
Reply:Originally Posted by lotechmanThe point I am making is that often weldments are built to ridiculous tolerances.  This costs time and money.  The designer sticks his chest out so proudly and boasts that the completed monster is plus or minus one millimeter but doesn't take into consideration the cost.
Reply:In the end we all have to walk different paths.  I do urge you to reconsider that 1mm between beam flanges is beyond belief.  This is not distance between bolting surfaces.  I am talking about the flange part of a wide flange beam that varies plus or minus an eight of an inch when it comes from the rolling mill.  To expect the bottom of two beams to be perfect alignment over the span of a bridge is not reality.  In structural we always build columns as close as we can with a tape and horizontal members on size or up to 1/8th short depending on length.  All holes are 1/16th oversize and in some cases 1/8th.  The worst case for an ironworker hanging steel is to have members too long.  The hole patterns are held as close a possible using conventional ironworker punches and hand layout.   If one was to spend time and money on greater accuracy one would not be competitive.  I can understand if you are involved in machine tool assemblies that tolerancing has to be close.  if however you are aligning by transit or laser there has to be adjustments such as screws on the bottom of legs or grouted pads.  Spending time getting a leg the exact length when you are going to use an adjustment mechanism is wasteful of effort.  Tolerancing properly applied is efficient.  Not properly applied and the job goes over budget.   That is my motivation for presenting the idea of flame cut copes as an alternative to mitre cuts.   I can relate to lazy CAD practices.  I have encountered a 30 metre section of a hull with no total length nor running dimensions.  The longest given dimension was 1020 mm which was the frame spacing.  I did a building where the dimensions were given to one hundredths of a millimetre.  Angles were given to hundredths of a degree.   I agree it is indeed sweet to weld up an assembly that has mating surface machined.  For me a saw cut is about all I ever see.Cheers
Reply:Originally Posted by lotechmanIn the end we all have to walk different paths.  I do urge you to reconsider that 1mm between beam flanges is beyond belief.  This is not distance between bolting surfaces.  I am talking about the flange part of a wide flange beam that varies plus or minus an eight of an inch when it comes from the rolling mill.  To expect the bottom of two beams to be perfect alignment over the span of a bridge is not reality.
Reply:Well gentlemen I think we can call this an arguement done...I have my ways, He has his, and she has hers.  Its alright and as long as we reach the same goal its ok.Now lets all have aIF it Catches...Let it Burn