how to chop a top...my way

ok, i am not claiming to be an expert, but i do have some years of experience as a bodyman and i want to share some pointers on chopping a top on a truck cab...i believe many of these simple to do reminders could help someone who is considering slicing their lid...anyone want to ask questons can do it here, no need for pm's on this thread...

here is the starting point...

you must have a good solid place to start... a cab mounted to a frame is ideal, but even then all mounts need to be checked to determine if they are "doing their job"
if the cab is not on a frame, you need to set it up solid, or at least on blocks, or in my case a table that is solid and sturdy enuf to support the cab's weight...

* pic 1

i used 3" channel (what i had) as "dummy" rails welded to my roll around table, then set the cab on it... i realized my truck's doors would be dragging on my table, so i then cut a couple of 2x4's and used them to raise up my cab slightly

*pic 2

i also checked my cab-floor structure to make sure it was solid enuf to use as mounting points...

*pic 3 & 4

you may be thinking this is a waste of time, but it is not-and a few minutes now can possibly save hours of heartache later

i am planning on offering this as a "help" and as such, others with more experience can offer pointers to me, and contribute to this thread as long as it is within the context of this subject

already i realize how easy mistakes are made...listing info on 4 pics, putting up 5...

so now i think pics will be left un-numbered and you guys can figure them out...on to the next step [P

with the cab mounted stationary (no weebly-wobbly[cl) i then HIGHLY RECOMMEND checking door gaps/ panel alignment...
your building a rat, you say- so why do this? simple... if the doors do not fit now they probably arent going to fit later but if you know HOW WELL they fit now, it will be a good reminder that they should fit later... spend just a few minutes making a note or 2- or a pic or 2 of gaps...- and remember that older vehicles' panel alignment is not as "consistent" as modern vehicles but that is no excuse to not do your best on your top chop...
once you know your doors open n shut decent, then it is time to BRACE IT UP!
again i stress, take the hour or 2 to do this right (i had metal already laying in the shop and it took me only a short time to tack them in place)
remember, a little time now in proper prep can save trouble later
braced front to back, and cross ways with simple 1" angle iron made it solid enuf to cut on...
pics...

another round of information-- i hope some one can benefit from it...

time to decide how much to cut out--ad more importantly WHERE to cut...

most people considering a top chop have seen a truck with one, and know about how much to take out... same with me, i saw a truck with a 4" chop and 5" cut from front so my mind wasmade up
so even though the amount is realy a matter of choice or preference, if you are 6'6" and considering a 6" top chop you might want to rethink it

also ya need to consider where these cuts are going to be made-things like interior panels, reinforcements and even exterior body lines all need to be considered if you are about to remove a portion from the body...

so make your marks -masking tape is a cheap way to mark your area to be removed and helps you with visualizing body lines - and then recheck all interior "obstructions" use your tape measure ALOT right now...
make sure you have everything like you want it.... then mark the lines where you will cut with chalk, a pencil or something that wont peel off like the tape can...

more pics...[P

time to cut! almost!

well i stress again, be sure to check for any obstructions, and remove any flammable "stuff" from the area before cutting...

what to cut with... i used a sawzall with an 18 tooth-per-inch blade on my first cuts... used a slower speed to help control things and got a very decent and clean cut quickly...

a cut-off weel on a grinder would work as would a few other options possibly... i hope others can offer their "tools of choice" to this list...

i cut the top cut first, this keeps me from having to "wrestle" the top of the cab tryng to cut out the section to be removed...

i then did something others might not do-but this thread title says doing it "my way" so here it is... i cut a 1" piece from the rear section before removing the rest... i will explain.. i will use this 1" "strip" tacked in on the back side as a "filler" to help with ease of lining up and welding that flat section... the pics will show it better than i can explain i hope

i found when i went to use the sawzall on the second line of cuts on the rear of the cab that the shaking was more than i wanted... i could have used a cut off wheel, but i have a plasma cutter that i am fond of and used it and a straight-edge for a guide to cut the back of the cabs' 4" section out

i then fit (-some material had to be removed from them length wise) and tacked my filler strips in on the back side....

i was out of time and was going to need the space, so i set the roof back on just for some idea about how much trimming and fitting would be required...

here is what i found...

the back lost about 1/2" of width overall--not to bad, and can be easlily massaged to tolerances...

the front will need more attention as i am NOT planning on cutting the roof in half... yes a little more time, but the attitude i am wanting needs the leaned pillars i think
the pics show how much movement will be needed to get everything lined up again

it would be easier it seems to just spilt the roof, but i do not want to weld all across the roof itself either, so i will work the pillars and make it work...eventually

this is all for now...if anyone thinks this is helpful i will continuie the "info-thread" if not it will end here...[P

I want to see how it ends......

me too[ddd

So far,So good!

Nice write up, keep on preachin' brutha!

Subscribed

Will be watching for sure, going to be chopping mine in next couple weeks hopefully.[P

I have nothing to chop but i still enjoy watching you metal wizards.

Got one coming up in the future, need to learn as much as I can, carry on please.

i really appreciate the encouragement to continue this thread...

the part you guys may not want to hear is that it will be about a week before i get to touch this cab again.. but i promise to document its progress here.[

and i certainly dont claim to be a metal wizard, but am sure having fun playing in the shop...especially when my boys help

trying a different way to load my pics--this is only a test...

Doing some good work there!
I'll be interested to see how you lean the pillars. I cut my roof in quarters to get all lined back up.

I used your same scrap backing trick you used for my section. It worked out great since my cuts weren't perfect. The backing provides a nice place to weld without blowing through.

I prefer to stretch and add a filler strip down the center of the roof, rather than lean the pillars back.


it's a matter of taste, but the leaned back posts just look a little wonky to me.

leaned posts wont be that apparent on this mild of a chop...but it is still easier IMO than welding across 4 feet of flat metal on a split roof trying not to warp it up...[
if this was a different body style i might have even attempted the split, but these are cool done this way i think--and me n my boys r the ones we hafta make happy on this build



and you know what they say about opinions....

...they are like armpits... everybody has them, and some of them stink

ok so i had 5 extra minutes to work on fitting the roof to the body... as most understand, an angle chop (5" removed front/4" rear) requires a little more to fit because the cab corner needs to be cut at the front some more to fit with the "sloping" of the roof... the pics will show how i marked off to get this angle cut out of my cab corners...
after putting the roof onto the body, the amount needed to trim could be seen as the front of the cab corners touched and the back of the cab was "wide"
so here is how i marked it or the trimming...
i used regular masking tape and taped it flush with the edge of the "body's cut" this caused an overlap on the roof panel...and i marked it on the roof panel,then removed the tape...
next i put tape on roof at its cut edge, near rear glass-- and used that "difference" as my guide to tape all the way around corner using same gap to the first chalk mark, this showed me about whatneeded to be trimmed and makes it a little more accurate and quicker than many "test fits" though some "adjustments" will be neccesary...
next installment will be the fitting of the freshly trimmed cab corners and geting ready to make the front pillars move into alignment[

hotrod preacher said:

ok so i had 5 extra minutes to work on fitting the roof to the body... as most understand, an angle chop (5" removed front/4" rear) requires a little more to fit because the cab corner needs to be cut at the front some more to fit with the "sloping" of the roof... the pics will show how i marked off to get this angle cut out of my cab corners...
after putting the roof onto the body, the amount needed to trim could be seen as the front of the cab corners touched and the back of the cab was "wide"
so here is how i marked it or the trimming...
i used regular masking tape and taped it flush with the edge of the "body's cut" this caused an overlap on the roof panel...and i marked it on the roof panel,then removed the tape...
next i put tape on roof at its cut edge, near rear glass-- and used that "difference" as my guide to tape all the way around corner using same gap to the first chalk mark, this showed me about whatneeded to be trimmed and makes it a little more accurate and quicker than many "test fits" though some "adjustments" will be neccesary...
next installment will be the fitting of the freshly trimmed cab corners and geting ready to make the front pillars move into alignment[

Click to expand...

This is a great technique! So when you did your initial chop, did you take into account prior that you would be taking an additional 3/4" to adjust?
I know when I did my chop (first one ever with no guidance) I used tape to mark my entire 7" and made absolutely certain that I had an equal space all the way around between the tape. My method only really works if you plan on taking the same amount out front and rear (which I now regret since I have a nose up roof)

I'm looking forward to you leaning pillars since that's new to me too [cl