Reason number one why I prefer the Roper Whitney over the air punch. The design of the Roper creates a self centering mark in the plug which allows me to drill a perfectly centered hole in the plug. The picture shows the nice self centering mark.
[IMG]http://inlinethumb45.webshots.com/44524/2327995880102553149S600x600Q85.jpg[/IMG]Its hard to see but on the backside of the plug a small titty is formed from the self centering mark. Plug with the titty on the left and flat plug on the right.
[IMG]http://inlinethumb21.webshots.com/44180/2056459910102553149S600x600Q85.jpg[/IMG]To flatten the plug just use a hammer and dolly, one quick hit will do.
[IMG]http://inlinethumb02.webshots.com/25793/2486724270102553149S600x600Q85.jpg[/IMG]Once the plugs are hammered flat, I lightly clamp them in the vise grip and use a cordless drill to drill the hole. Since the clecos are 3/32 in size you want to use a drill bit around that size, dont go bigger then 3/32, I believe I used three sizes smaller then 3/32.
[IMG]http://inlinethumb54.webshots.com/25717/2228463580102553149S600x600Q85.jpg[/IMG]Not the greatest picture, but the plugs on the left are done with the Roper Whitney hand punch. The ones on the right are from the air tool. The holes on the left are all directly in the center, the ones to the right are off center. I just like the plugs to be holding an equal amount on each side versus being off center.
[IMG]http://inlinethumb54.webshots.com/20149/2524539040102553149S600x600Q85.jpg[/IMG]Better shot of off center holes, try to avoid off center holes.
[IMG]http://inlinethumb15.webshots.com/43278/2319677040102553149S600x600Q85.jpg[/IMG]Here is the reason behind making these metal plugs. Picture of the plug installed on the cleco. Now we have a cleco with the clamping force to hold a butt joint.
[IMG]http://inlinethumb40.webshots.com/43943/2045689980102553149S600x600Q85.jpg[/IMG]Cleco is released and the plug is tight against the bottom of the cleco. If the hole you drilled is to big the plug can move around and pull through so proper sizing is important.
[IMG]http://inlinethumb52.webshots.com/3571/2612633090102553149S600x600Q85.jpg[/IMG]My test panel, notice the tight no gap joint perfect for butt welding sheet metal.
[IMG]http://inlinethumb20.webshots.com/26003/2541504890102553149S600x600Q85.jpg[/IMG]Another view of the joint. One thing I like to do when aligning panels and I have the fit where I want it is to make some simple alignment marks across the two panels. The marks will help me see if the panel has shifted once I put the panels together for welding.
[IMG]http://inlinethumb62.webshots.com/20477/2092904180102553149S600x600Q85.jpg[/IMG]Installing the clecos to hold the panels. Not what you want to do but this shows the gap created. There is a trick to overcome this.
[IMG]http://inlinethumb60.webshots.com/12795/2073214770102553149S600x600Q85.jpg[/IMG]Backside of joint. Now you can see how the plugs come into play. Once again this NOT the desired affect meaning the huge gap.
[IMG]http://inlinethumb60.webshots.com/45499/2919278900102553149S600x600Q85.jpg[/IMG]With the panels clamped back together the trick to achieving a nice no gap joint is..... Drill a 1/8 hole in the center of the joint. You want a slightly bigger hole then the 3/32 stem on the cleco and 1/8 works perfect. Plus 1/8 holes are easy to weld shut after wards.
[IMG]http://inlinethumb21.webshots.com/45652/2087457430102553149S600x600Q85.jpg[/IMG]When drilling the holes make sure you clamp the panels together. Use long reach vise grips like what is shown to hold them tight.
You can also use a rat tail file if the panels are separated, just make sure you mark the location on both panels for the filing.
[IMG]http://inlinethumb57.webshots.com/17720/2537380110102553149S600x600Q85.jpg[/IMG]More holes drilled, nothing special, just keep moving the clamp down as you drill.
[IMG]http://inlinethumb60.webshots.com/43899/2715655510102553149S600x600Q85.jpg[/IMG]Once the holes are done you clamp them together. Clecos are installed and the result is a nice tight joint just like before.
[IMG]http://inlinethumb35.webshots.com/43362/2293301120102553149S600x600Q85.jpg[/IMG]Close up of the gap and a 1/8 hole. That gap will be a breeze to weld and so will the 1/8 hole. Much easier the the .040 gap left behind by those high dollar special clamps.
[IMG]http://inlinethumb24.webshots.com/43479/2746935630102553149S600x600Q85.jpg[/IMG]Another view
[IMG]http://inlinethumb16.webshots.com/45135/2358540190102553149S600x600Q85.jpg[/IMG]The two panels are sitting level and flush just like they should be.
[IMG]http://inlinethumb63.webshots.com/43198/2227878140102553149S600x600Q85.jpg[/IMG]Back side of the joint showing the plugs holding the panels tight.
[IMG]http://inlinethumb55.webshots.com/27958/2545630340102553149S600x600Q85.jpg[/IMG]They hold tight. Panels held with clecos and plugs are solid and with little movement. The only movement you get is from the cleco moving around in the 1/8 hole which sometimes you want to get that perfect alignment.
[IMG]http://inlinethumb40.webshots.com/43239/2109215210102553149S600x600Q85.jpg[/IMG]That's how you clamp a butt joint together with clecos. Sure it takes so time making the plugs but once you make them you can re-use them again and again. Plus you dont need to spend 20 plus dollars on four special clamps that create work. I bought my pliers and two bags of cleco clamps for about 10 bucks from an aircraft surplus store...Eric
