marking out bars for rails and gates

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hello i am pretty new to the site and there is a thing in fabricating i cant get my head round. if i was making a gate or rail and had the flat bar cut ready for punching or drilling i am wondering how to mark it all out.  i know the regulations is roughly to each bars should be  roughly 4 and half inch centres but is there a method of working this out or a tutorial anywhere.thanks
Reply:The spacing may be different depending on the size of your bars.  The rule in many places is to have 4" or less between bars, so 4.5" would be the spacing for 1/2" bars.Depending on how many you have to do, you can make a jig as complicated as you like, but I find it doesn't take all that long to lay out each one, especially if they are all different sizes.I used a Sharpie marker and started at the center, and then moved my tape to where any inch or half-inch was at the center mark and then clamped the tape to the bottom and top bars, which at this point have been cut and are lying next to one another.  I got pretty good at moving 4.5" at a time and making a line on both bars at the same time.I always used tubing for top and bottom bars, but you may find a similar strategy to work for something else.
Reply:Originally Posted by brooker2006ukhello i am pretty new to the site and there is a thing in fabricating i cant get my head round. if i was making a gate or rail and had the flat bar cut ready for punching or drilling i am wondering how to mark it all out.  i know the regulations is roughly to each bars should be  roughly 4 and half inch centres but is there a method of working this out or a tutorial anywhere.thanks
Reply:Originally Posted by BrettI have written an Excel program for that on level and stairs.Its adjustable to different angles, width balusters and maximum spacings. Let us know if you want a copy.
Reply:No dramas Steve , I'll shoot it over tomorrow . Its at work and its Sunday evening here.Do you have much experience in Excel?A good guess is better than a bad measurement
Reply:I always use spacer blocks. Cut two pieces of tubing at the length you need(sounds like you need 3 1/2") and use those to get your spacing. Make sure to alternate your blocks, just in case one is slightly longer than the other, you won't end up with crooked pickets at the end.The regs are 4" maximum. If you set them at exactly 4", You are right at the limit, so a 1/16 can cause big problems. If you set them anywhere under 4 is always better for me.
Reply:Brooker and Steven ,I have re written a simplified version but cannot send it via Welding  Web  messaging.I can be Emailed [email protected] I'll send em over BrettA good guess is better than a bad measurement
Reply:If I'm going intermittent tacks that are 1" long, and on 6" centers, I take 6-1=5...therefore, I start on my tape at 0 and mark the following points:1,6,7,12, ect...In other words, I mark out a 1" space, followed by a 6" space, and repeat.  You can do the same with your application.
Reply:Make a jig with the proper spacing between the bit or punch and a stop.  Punch or drill away.  As you advance your material the hole should drop over the stop.Take note.  punching spreads the material. So check your holes often to make sure they line up.  60 punched holes in 20 foot material can vary quite a bit if you are making mated pieces.
Reply:Originally Posted by brooker2006ukhello i am pretty new to the site and there is a thing in fabricating i cant get my head round. if i was making a gate or rail and had the flat bar cut ready for punching or drilling i am wondering how to mark it all out.  i know the regulations is roughly to each bars should be  roughly 4 and half inch centres but is there a method of working this out or a tutorial anywhere.thanks
Reply:This is the problem. it is called "tolerance stackup".Lets say you have 50 bars to install. If each one is off .020 of an inch and you multiply that by 50 you will be off , if you start at one side and move doen the line.The best way to not have tolerance stackup is to make a fixture to keep the distance and keep the bars parallel. If you try to use ANY KIND of marker you will be off in the end.ALSO if you start in the middle and work your way towards each end and you have a uneven or narrower space at the ends then it will be symetrical and look INTENDED.
Reply:I agree with Donald there, over here we call it "accumulative error", its a killer on long runs.If you have to mark and fix, a progressive measurement ie. marking 10,20,30,40 etc is far better than 10,10,10,10. Firstly  your error wont accumulate also if you mark one wrong , only one is wrong not every one after that mistake (been there , done that! )A good guess is better than a bad measurement
Reply:There's a reason many drawings will have multiple dimensions pulled from the same reference point.  It avoids having the measurement tolerances stack up.  In other words, you're ok to lay out all the marks, if you leave the end of your tape in the same place for all of them.  If you move your "0" from one mark to the other, you can stack up error.
Reply:I just use the prepunched bar from King metals. The holes are where you need them and can be used as a jig. They have them in every spacing and for every size picket and for round and square. And if you get the prepunched bar the same width as your top and bottom bar they self center. You just cut one side out so you can slide your pickets in to weld. These bars are relatively enexpensive and save a lot of time whither your welding or just marking. Attached Images
Reply:Cool Idea, Bob.  Thanks
Reply:bob, that is how i have made my panels.  i thought i had an original idea.  you must be a genius
Reply:I built 165 feet of safety fence for my pool recently, mostly in 10 foot panels, with two 3' gates, one 5' gate and two 7' panels. My solution was to build a 10' long wooden jig so the 4" spacing of each picket and each panel was exactly the same. There were spacers attached to the jig which also centered the pickets in the thickness of the rails. The rails are 1"x1"x14ga square tubing, and the pickets are 1/2"x1/2"x14ga square tubing.In addition to the ease of spacing, the ease of assembly was greatly improved. Using the jig I was able to make at least two 10' panels per day working alone. Any other method would have taken me twice as long.BTW, this was my very first "large" welding project and I have only been learning to MIG for a about a year. I think it ended up looking very nice and I saved a ton of cash!I have attached a couple of pics. Attached Images
Reply:Nice job.  How did you attach the fencing? I know of a couple of shops that use wood jigs.  They do it on 4x8 sheet the set the sheets aside when not in use.
Reply:Thanks! I am pretty proud of it!The rails have vertical 1/2" holes drilled 1/2" from each end. These holes match up to two pieces of 1/2" rod welded to 1"x 2" flat bar which is welded to each post. The holes in the rails sit down over the 1/2" rods, and the panels are easily removed for maintenance, access, etc. The bottom 1/2" rod/flat bar brackets are raised slightly relative to the rail spacing so the bottom holes/rods can match up before the upper ones. Makes it easier for one person to install a panel.I hope my description is not too confusing.
Reply:I got it and can see it.  Good Idea.  I'll probably use that it.  Minimal to no onsite welding.  Looks like you welded on top of the flat bar.  If so, a hole drill and welded on the opposite side of the flat bar might have cosmetic benefit and less likely to break off in twisted.No taking anything away from your job.  When I finish a job I always look for things to improve upon.Thanks for sharing.
Reply:You are correct...the welds are on the top of the flat bar, which, in retrospect I hate, but at the time I built the fence, I didn't have a drill press and drilling all those 1/2" holes in the flat bars was not in the time budget! The welds are strong though, and I have yet to break one. I have, on the other hand, broken one of the flat bar pieces off the post. And yes, the on-site welding was limited to welding the hinges and latches for the gates, all of which could have simply been bolted instead. Looking back, that is what I should have done.I too look for any improvements I could have made after I complete a project. Learning by mistakes is better than by experience in my book.Last edited by MIG-ateur; 06-10-2008 at 01:39 PM.Reason: Left off some info