Newbie gathering CHOP information

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rainbow lungs

Well-known member
Joined
Mar 8, 2012
Messages
258
Hey everyone.

Newbie here. Actually did two intro posts!!!

I am gathering as much info as I can to chop the top on my 39 chevy truck....pic of it attached.

Pictures, what works, what didn't work.

How you went about chopping yours.

Best and easiest way to chop this style truck.

I would appreciate any help I can get.

Thanks Lungs
aka Bob
 

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Lots of 39-46 cabs on here. Do a search, some helpful info on here.In the mean time your welcome to check my build thread.
 
Got it read it slept it.

Lungs

I'll give.


BRACE BRACE BRACE!

I took off my doors, then did a diagonal brace from the bottom front of the door to the back center right below the belt line.
Then I did did an x brace across the whole inside just under the belt line again and made sure to weld the middle of the x to lock it in.
Always add more cross bracing then you think since the less it moves (and it will move a little) the better.
I quartered my roof since I didn't want to lean my pillars back so that's a bunch of work.
When you chop, I used blue painters tape to make my 7" mark all the way around. Nice straight lines are your friend here.
I started putting mine back in sections. First the front section (tacked in place) then the rear (tacked into place).
You'll want to make your major adjustments now cause once you start laying beads, there's no turning back. Actually, once you cut the top off, there's no turning back :cool:

Once I had it all tacked and close to where I thought it should go, I cut off the top door jambs and installed the doors. It helps here to have your bracing just inside the door jambs.
I then started putting the top door jambs back together. I was able to use the drop off the door jamb from the side on the top, since now my too door jamb is longer. It took some doing, but they line up pretty freakin well.

Once you are 100% confident that everything is placed well, I cut strips to fill the giant cross missing out of the roof. Again, I used the chunk out of the back of the door jamb from the roof on the top above the door to match profiles.

Forgot to meantion that I used strips of sheet metal to support the cross section from moving all over.

One thing I learned doing mine it TAKE YOUR TIME!!!! You DON'T want to just go to town welding a whole seam. The metal will get too hot and warp all over the place! Tack every couple inches over here making sure the edges all line up, then go to the other side. Only use tacks not full beads.

Your pointer finger will get a heck of a workout :cool:
 
Boneheads 39 build is a good start. Hot Rod Preacher has a thread going about chopping a top - don't recall what exactly, but you can get some ideas there too.

Do you want to lay the A-pillars back or keep them upright? Do you want to have a rake? How much are you going to chop?

My 2 suggestions: Go to the 'Builds' section, sort by 'Replies', and start going through them.

The other suggestion is to start a new thread titled something like "39 Chevy cab Chop - info/help?" That way the guys that have done one will more likely open the thread.
 
Thanks for the info.........

Sam you posed a good question I have to ask my self bend um back or keep um straight. SO what's better...easier....the downside to both.

DO all 39 chops need a piece cut out through the center?

Going to go look at Boneheads build right now.

Thanks Lungs
 
DO all 39 chops need a piece cut out through the center?

Since I've only chopped my Olds, I'll be general. That said, you either lean the pillars back or add a section in the roof. The same goes for leaning them in - if you don't, you'll need a splice in the middle. The only other way to do it is to have two roofs. The more you chop the more the lean or the bigger the splice.

I usually don't care for the leaned back look as much - personal preference. Leaning them back makes getting the door frame harder to get right. Splicing the roof requires patience or you'll warp it bad. Basically decide the look you want and go for it.

Make sure you keep the front glass holes flat or your glass will crack when installed.
 
70 mustang on killbillet did a nice job on an early 40s

I have that book to and it helped some like the "weld a rod to the center of your windshield to keep it aligned. take your dash out to weld your braces to the support behind it and save ruining a good dash. I used thier paper template idea to keep the measurements constant also. PLEASE DONT CUT YOUR DOORS TWICE! me and another guy on here made this mistake. cut the tops off when your chop is all back together then shut the door and measure and you can tighten up even factory gaps! I used a hydro jack with an extension in the cab to lift and lower the roof panels a hair as I taked it together. Last neat Ideah I didnt use was in a mag I have this guy tacked it sparingly back together after he was about ready to weld it up then ran a sawzaw our grinder blade threw the cut cause it evened the gap for an easier but weld. if your off 1/16th here and there youll end up with an 1/8th in rusty thin metal and this helps straighted that out for less gaps. almost forgot welding store sale a "roll and measure" its just a roll of rubber about 3" wide that helps alot for straight lines.
 
Last neat Ideah I didnt use was in a mag I have this guy tacked it sparingly back together after he was about ready to weld it up then ran a sawzaw our grinder blade threw the cut cause it evened the gap for an easier but weld. if your off 1/16th here and there youll end up with an 1/8th in rusty thin metal and this helps straighted that out for less gaps.

That's a great idea!!! Wish I woulda heard that prior to my chop!
It's amazing how 1/16" can cause a big headache, especially when it's a few 1//16" gaps all together to make a 3/16" gap:eek::rolleyes::D
 

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