Knighthawk's chop job 101

[knighthawk]

As some of you know, I chopped my '48 Dodge 4dr, and I have been asked by a fellow member, as ''how'' to chop a car, so I thought, maybe you guys would like to 'read' along..... over at www.hotrodders.com/forum, I had a thread going of the complete project on a thread called...."another chop job''. It has about 20 pages of pictures and conversation, and getting close to 23000 veiws... So .....between here and the Hotrod place, I'll tell (show0 him my process.... FIRST : chop it on paper , take 2 pictures of your car, side profile, cut one pictures in half, along the roof line, then you can take the 2 halves and overlap it, or lower it, to see what it will look like....here are some before and after pics....I got some newer ones of the car, with some old school wheels on it , but I can't find them, but this 'll get you started....

[randroid]

knighthawk,

I have no intention of chopping my car nor taking part in anyone else's, but that doesn't mean I'm not interested in how it's done. Looking forward to reading your posts on it.

-Randy

[knighthawk]

there various reasons for chopping a car, as in my case all I had was barnyard shell. And it was something I always wanted to try, and eventually built the whole car. Maybe I can help the next guy a little, as it sometimes took alot of looking and thinking , and asking alot of questions.....like bdfore you make the first cut.....

[randroid]

knighthawk,

So, do you feel hacking-up old iron as your personal penance for living in SE Kansas?

That was a joke! I don't care who you are, that there was funny! Sorry, I couldn't help myself, but people from Colorado are known to say such things. So are Texans. Put a Texan and a Coloradan in the same room and things can get very ugly very fast and the strange part is we like each other. Go figure.

Back to the topic: I read all the threads here on chopping because I'm fascinated with the thought and the geometry necessary to do such a job and have it finish as nicely as yours. So many compound curves that must be married smoothly while maintaining not only a clean flow to the body but also retaining the shape you originally visualized. To me a chopped car done well is the realization of original thought. Not done expertly and it can look like the evidence of having both a torch and an old car while you're drunk, which is how so many seem to be.

As I said earlier I'm anxious to see the step-by-step with descriptions of how and why you chose then accomplished each section.

-Randy

[knighthawk]

OK, The VERY FIRST thing , is to brace everything, lots of criss crossing in side at the top of the door, bottom of the window openings, Once you remove the top, nothing is left to keep it ''square'' , and don't forget the rear window opening , brcae this good also or the curved glass willl not fit back in ! The window post are called 'pillars' , first one by the windsheild and/or vent window is the "A" pillar. on a 4 dr, the post between the doors would the 'B' , the rear door to rear Quarter is the "C' pillar. Place some tape on each pillar , position dosen't matter, just choose a straight or square point to cut, less taper, the better I used 2'' and 1'' masking tape to mark out the cuts on the pillars. I went with 2'' at rear and 3 at the front. You can always cut more out, but harder to put it back in. Cut the pillars , take out the selected 2'' or 3'', leave the rear metal across the rear window attached, in my case I left about 6'' atached above and below the rear window to act as kid of a hinge. Once the roof is 'free' except for the 'hinged' area in the rear, pull the top forward and down to the shortened pillars. By pulling the roof forward and down it also lowered the the rear window profile, or, hump. At the 3'' my top lined up almost perfect with the shortened "A'' pillars. At this point you will realize the none of the pillars will line up perfectly . Because the roofs are narrower at the top than at the bottoms, the roof will be shorter AND narrower as you lower it . If you want to pull more forward or lower, you will have to cut the roof across the top from left to right, and weld in a strip , usually about 2'', the same goes for the width. Place the lowered top on some block and look at it for a long, long , long , time........next ; hammer welding

Edited July 1, 2011 by knighthawk

[yourpc48]

Great job. I Chopped my 36 ford PU years ago. It was allready a dune buggy when I got it. Like yours a shell and mine had hardly any of the original body untouched. SO I decided to go wild. In building the truck I only used body parts that had been discarded by people that had the same body truck as mine (rear fenders, running boards, etc.). My before pics are in storage in Alaska but here are a couple of afters:

I am not an extreme restorer or hotrodder. I enjoy both!

[knighthawk]

now that you have the roof cut loose, you need to decide how much to .,lower it. You know now that the more you lower it, the longer it has to be to reach the windsheild. This is accomplished 2 ways cut the roof in 1/2 from side to side and adding a filler strip creating 2 welds all the way across , , or , taking a 2nd roof, cutting it to fit the original, leaving you with 1 weld. The welding and warping willl be critical here, as a ripple in the finished roof is not a good thing ! Then you get to practice metal shrinking, which is kinda tricky also. Also, where you cut the roof in half, depends on how hard it will be to weld and hammer the seam, as you will need to be able to touch both sides of the weld at the same time ,all across the top , as in hammer and dolly work .... Use a wire feed welder ,using spot welds, spaced out to keep from building up any heat, grind the bead down to about .050 on BOTH SIDES, ( I just used the wire I was using as a guide as high to build it ), Hammer it flat (stretch it). What happens is, the spot where you weld it ,now I'm talking just a spot weld, this "spot' will get hot and expand out over the immediate metal, creating the high spot, and as it cools it will contract, and cause the warpage, so , by hammering it flat, you remove the high spot, and spread the metal back out , . So you will make a couple spot welds(one at time would be better) put down the welder, pick up the hammer and dolly, pound it flat, put down the hammer and dolly, pick up the welder,..... that's assuming you didn't put too much (high) of weld and need to grind some off first. Personally what worked good for me was to make a couple spot welds and cool them eimmediatelty with the air hose, then come back and hammer them cause once they cool , they are done moving. Also, you need to spread your spot welds out, like 1 at each end, some in the center, get a few very foot or so, then every 6 inches, you need to be sure to keep the original spacing of your seams.....soon you'll have some this .........

[knighthawk]

another thing to consider is.... the sides of the roof will also need to be wider as the top comes down. This means you will have add some material to make it wider, either along the sides ( driprail area) or in the middle. Rmember you have to be able to work both sides of the welds ( hammer welds ), so unless you got long arms......I thought I would cheat a little and push the tops of the doors and door channels in some to make it a smaller gap. By moving the tops inward, it changed the alingment of the window channels, I had to move them inside the doors, then they hit the door latches, had to move them....no a good idea ! The pillers or door posts widths will change also, so they will need some 'pie' cuts to match them up,, then you get stuff like this.............

[randroid]

knighthawk,

I'm finding your insight and progress amazing!

-Randy

[knighthawk]

just remember that the whole project has to ''flow , you know , smooth lines , to make look ' factory ' . You may have to add some thing here and there, on the trunk, for example, a peice of sheet metal added here, removed the dip in the area between the trunk and the rear window. If I could have found another rear window or smaaller one, I would have lowered ther rear a littl more........ the rear quarter windows took as long to 'build' as did the rest of the top. A good thing about a project like this , is if you couldn't weld before, you started this project, you'll be pretty good by the time tour done ! .......I hope this gives you guys a kind idea of how to and what's involved it a chop job

[randroid]

Knighthawk,

Thanks very much for going to the trouble of posting that. It gave me a new perspective into the art that I have not had in the past.

-Randy

[hkestes41]

I have seen Knighhawk's work in person while still in progress before he had the interior done. He did a great job, everything was aligned well and the welds were great.

I have never done a chop myself but would imagine that he picked one of the more complicated cars to do it with. Being a 4 door and with the slope on the rear of the top to the trunk to keep in proportion.

[knighthawk]

thanks, hkestes41, for complement. Ant time you're in area, stop in again. Although these pics and postings may not ne a professionals veiw of the chop, but it kinda gives the rest of you a general idea of how it's done, some are harder than others,,a early pick up with a straight up square cab would be a lot easier.... hope you all enjoyed reading this .