tech: realligning chopped pillars aka how to PieCut

[Nick]

Decided to start articles on basics of welding/fabrications to help others out. So here's my 1st one. Let's say you want to chop a top or something similar. This will require you to remove a section of the pillars then weld them back together. But the pillars aren't always square and flat nor the same thickness. WHat you'll run into is one end of the pillar maybe an inch or so thicker then the other end you're trying to weld onto. That's where pie-cuts help.

Let's take this bus hatch for example. Stock:


Once I removed roughly 5" to the length of the pillars, they no longer allign. Always align from the glass/rubbber lip, then work everything around that. Or else the glass and/or rubber may not fit properly anymore. As you can see on the picture below, the top part of the right section is taller at top but thinner at the bottom. We can fix this be either making the left section thicker at top or make the right section thinner at top, then make the bottom left section thinner or bottom right section thicker. Or do both and have them meet in the middle somewhere.


What I decided to do it to make the top part of the right section thinner (move it down) and mke the bottom of the right section thicker (move it down). I cut slits into the sides, the longer the less obvious the curve will be. So I made my cuts about 6-8" or so. On the top part since I wanted to make it thinner, I hade to remove more materials from the middle of the cut so it can be moved down. So really I cut a pie-shaped cut (the color red in picture below)


So now bend the metal into shape and weld them flush. I jammed a screwdriver in between the cuts and forced one sie up or down until it's flush with each other then spot welded them together. Now both parts have alligned glass lips and pillars are the same level again. Just finish up the welds as normal and you;'re done.


Here's the bottom part where I made the pillar thicker. Just push it outwards instead of inwards.


Sometimes the post maybe a different shape in all 4 corners. To me the easies to re-allign these is to cut 4 slits in the middle on all 4 sides, then tack weld the corners together once alligned then weld the slits back up.

So now you have a chopped window section (or whatever it is you're modifying). Well of course I'm not done this yet but you know...

[hotrodheb]

Woo Hoo, Nick is working on the Runtrod again! [img]style_emoticons/<#EMO_DIR#>/Dancing.gif[/img] Oh, nice tech too! [img]style_emoticons/<#EMO_DIR#>/bowdown.gif[/img]


Keep it up!

[grumpy]

I am with Rob, glad to see Nick back at it. I wonder how the back end will do, bet its gonna be fun (this is to bait the thread, I have seen inside/top secret pics) [img]style_emoticons/<#EMO_DIR#>/cool.gif[/img]

[J_J_]

Nice to see ya working on it man!! [img]style_emoticons/<#EMO_DIR#>/biggrin.gif[/img]
another thing which has become habit for me, not just for alignment issues but also for structural integrity is to put in a sleeve. [attachmentid=10145] this is the B pillar on mine.
helps with the finish work too. just remember to lightly coat things with some weld through primer to help prevent corrosion.

[Flipper_1938]

<div class='quotetop'>QUOTE(J_J_ @ Mar 30 2006, 08:31 PM) Quoted post</div><div class='quotemain'>
Nice to see ya working on it man!! [img]style_emoticons/<#EMO_DIR#>/biggrin.gif[/img]
another thing which has become habit for me, not just for alignment issues but also for structural integrity is to put in a sleeve. [attachmentid=10145] this is the B pillar on mine.
helps with the finish work too. just remember to lightly coat things with some weld through primer to help prevent corrosion.
[/b][/quote]

Another trick related to this.

If you think you need more weld surface for structural reasons (narrow part with limited access), instead of drilling holes for plug welds.....grind a slot with a cut-off wheel. Fill the slot in same as you would a hole.

Sorry, no pictures here at work.

[speedfreak]

Thanks for this thread Nick, it helps alot when you guys that have done these types of things like piecuts and alignment issues, show us welding newbies some tricks. so I have a question then. how small of a piecut do you need when you are making a patch for, lets say, the lower corner of the windshield channel. you need to bend a piece that already has a 90 bent into it, so now you need to piecut it so you can bend it to fit into the window channel. is it more of a trial and error, or do you have to figure out the angle of the piecut? [img]style_emoticons/<#EMO_DIR#>/Idunno.gif[/img] the thing is, the lower windshield corner is one wild curve.


Larry

[Nick]

So you mean you want to make it cuvre tighter or looser to fit? Here's how I made one of my corners tighter. You should cut only the lip and the parallel surface (cut the part that curves), and make multiple smaller pie-cuts so it won't be too obvious. You'll have to cut on the other side of the lip as well, so basically cut everything EXCEPT the lip.




Here's my 1st try, the end result just looked like a hack job, so more less obvious pie-cuts is better then a bigger more dramtic pie-cut if you want to reshape a curve



Now if you want to make it more tighter, it's almost the same thing. But you there's only a small distance you can make it looser or will create wave points (speed bumps). What I've found it's sometimes easier to use the factory curve as is instead, just relocate the entire curve itself forward or back instead of moving the frame to meet the curve, makes sense?

more on my pillars here:
http://www.runtrod.com/runt-doorframe.html

[speedfreak]

That works, Thanks Nick. what I'm doing is filling in the defrosters on the dash. that curve on the inside of the windshield is a bitch to get right, even with posterboard! or it could be that [img]style_emoticons/<#EMO_DIR#>/imwithstupid.gif[/img] [img]style_emoticons/<#EMO_DIR#>/funny.gif[/img]


Larry

[JoeBoy]

Here's a couple of pics from my car. The pic of the quarter window has some pie cutting and piecing together of several window openings to get it right. I still have a bit more welding to do on them, but I'm satisfied with the shape of the windows.

The other is on my door frame. I had to cut it open and put in a filler piece to achieve alignment.