Chop question

phat46 · April 02, 2005, 04:49:28 PM

I got a wild hair today and decided to chop my '40 p.u. cab. I was going to do it sometime anyway; like next winter, but it was sitting there all stripped and gutted on the shop floor. Now is the time to do it.

My question to anyone who has chopped a '40 before; is it easier to move the windshield posts to align with each other or to align the posts and then add a strip across the roof to line up the back of the cab? I'll add a couple pics so you can see how far off they are...

enjenjo · April 02, 2005, 05:45:48 PM

Depends on the look you are after. Leaning the posts back make it look racier, kind of fits in with what you are building. Stretching the top is somewhat easier, but that is even better if you can come up with a second top, so you only have one seam.

phat46 · April 02, 2005, 06:03:24 PM

Quote from: "enjenjo"Depends on the look you are after. Leaning the posts back make it look racier, kind of fits in with what you are building. Stretching the top is somewhat easier, but that is even better if you can come up with a second top, so you only have one seam.

I do have another cab, and the only thing that is any good on it is the top of the roof. I think that would be easier too. I chopped 4" out of it and there's not a lot of post left to lean back. Upon closer inspection I see that the back edge will need some reshaping even if i do lean the posts back so i think i could take a section from the other roof both across the width and a piece from the cut across the top to the rear window area to widen the rear of the roof also. First I will ponder on it over a chicken pot pie...

chopper · April 02, 2005, 06:29:00 PM

Enjenjo's got that right in one! Work out how much longer the roof needs to be to allign at the back as well as at the screen pillars and make a template (out of butchers paper?) to mark the roof approx. halfway towards the back for the cut, and then use the same template cut shorter by the lenth that the roof needs to be stretched to mark that second roof. Make your cuts ( staggering them to spread the weld area on the roof if you feel comfortable enough to go that way) and then make cuts on the screen pillars top & bottom so you can allign them (as you already know the top section of the pillars are now a bit closer together than the lower ones) and making some strategic cuts, or complete new panels also allign the panels at the rear of the roof. Or maybe you can just pack that sucker and send it down thisaway for some aussie style of choppin'

Chopper

1FATGMC · April 02, 2005, 06:36:53 PM

Quote from: "phat46"I got a wild hair today and decided to chop my '40 p.u. cab. I was going to do it sometime anyway; like next winter, but it was sitting there all stripped and gutted on the shop floor. Now is the time to do it.

My question to anyone who has chopped a '40 before; is it easier to move the windshield posts to align with each other or to align the posts and then add a strip across the roof to line up the back of the cab? I'll add a couple pics so you can see how far off they are...

The picturs above are from the Dec. '88 R&C when they did the "Little pages" from the past. It is what I used to chop the top on my truck. If I can find the magazine again I'll put better pictures on my SITE.

You will most likely have to cut into the A post top and bottom and bend both no matter what to get them to align. They will probably need bending fore and aft an in and out from the sides.

I added the filler piece and didn't have to cut the top into four pieces, but I did have to cut it into 3 pieces. The front from the door forward was one and the back was cut into 2 pieces. That way the back corners could go back and also out to the sides. They still needed a number of relief cuts vertically to get everything right. This resulted in a second strip coming from the center of the back window up to the cross strip.

I did about 2/3's of the chop throught the back window and also dropped a cut on both sides of the back window to underneath it and cut 1/3 of the chop out below the back window (see the second picture above). I like the extra vision, but I also like the looks of the "mail slot" back window on some vehicles.

My top chop was a little over 3 inches. More and I would have had to cut the front 1/2 of the top in half and moved it out to keep alignment with the doors (so the top would have then been in 3 pieces).

Hope you had the doors all hung with good hinges and aligned good before you started. I didn't and really fought it later, but I also sectioned the body.

Getting the door tops all cut and pieced together was also a lot of work. A lot of people just don't know how much work goes into chopping a vehicle and your's and mine are easy compared to some cars.

Good luck,

Sum

phat46 · April 02, 2005, 08:07:16 PM

You will most likely have to cut into the A post top and bottom and bend both no matter what to get them to align. They will probably need bending fore and aft an in and out from the sides.

Actually the A post line up really well, no cuts would need to be made. I welded a couple "guide" pieces into the lower part of the A pillers and slid the top over them and they lined up almost perfectly. Any misalignment was less than an eigth of an inch and could be moved by hand into alignment.

I added the filler piece and didn't have to cut the top into four pieces, but I did have to cut it into 3 pieces. The front from the door forward was one and the back was cut into 2 pieces. That way the back corners could go back and also out to the sides. They still needed a number of relief cuts vertically to get everything right. This resulted in a second strip coming from the center of the back window up to the cross strip.

That's what i plan on doing also, cutting it into three peices as you describe. The extra top i have is shot both at the windshield area and at the seam above the rear window so i cant use a half from that top, only strips.

I did about 2/3's of the chop throught the back window and also dropped a cut on both sides of the back window to underneath it and cut 1/3 of the chop out below the back window (see the second picture above). I like the extra vision, but I also like the looks of the "mail slot" back window on some vehicles.

I cut 4" out of mine, the window is small already so I cut two inches above it and two below to keep the window centered.

My top chop was a little over 3 inches. More and I would have had to cut the front 1/2 of the top in half and moved it out to keep alignment with the doors (so the top would have then been in 3 pieces).

enjenjo · April 02, 2005, 09:23:41 PM

If the second top you have is bad around the edges, do your top so it is done all round the edges like a sunroof, and use the second top to fill like is done on a 34. this puts the seam in a high crown area, with a weld around the top instead of across the center, it's much easier to finish.

GPster · April 02, 2005, 09:26:50 PM

I chopped a '48 Dodge pu and lengthened the top and kept the glass angles stock. My feeling is that when you leave the top the stock length and slant the windshield back the cab gets kind of clastiphobic and your forehead is getting awfully close to the windshield. Also if your doors have vent windows they get awful busy. My Dodge had vent windows and I removed them but left the roll-up windows stock and just couldn't roll them up as high. I made a glass filler piece to fit where the vent window and assembley was and made it so when the window was rolled down you could just slide the vent window filler back into the window opening and store it behind the seat so that the whole window opening was open for fresh air crusing. I cut up another cab roof for pieces that had the rain gutter in them and split the original top from one side to the other about half way between the front and back. Rather then all the welding and finishing I just put a "Moon Roof" in. One other thing I did and it probably only applies to the Dodge 5 window cab. The quarter widows and the back window were not as tall as the windshield and door windows. I cut clear accross the back of the cab under the windows. I then chopped the top enough to make the door window openings the same height as the quarter windows and the back glass. GPster

phat46 · April 02, 2005, 09:56:22 PM

Quote from: "enjenjo"If the second top you have is bad around the edges, do your top so it is done all round the edges like a sunroof, and use the second top to fill like is done on a 34. this puts the seam in a high crown area, with a weld around the top instead of across the center, it's much easier to finish.

That's a great suggestion Frank, the "good" top was all dented up from life as a farm truck with Bondo about 3/8" think over most of it. Very lumpy and dented. I did get most of the major lumps beat and shrunk out of it, but it would stll need a layer of mud to make it smooth. If the other top is flatter I will try it like you suggested.