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Old 12-24-2002, 02:03 PM
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Post Top Chop to '50's Pickup.

I have responded to a board member's request for information about my chop. Since wrote the following to him, I will share it with all. My project was a 3 1/2" chop to a 1950 Ford F-1 pickup. The principles will work with any pickup chop. I also recommend a book by Tex Smith called how to Chop Tops which is available from Amazon.com. I wrote as follows:

I am happy to provide a little guidance on your chop which is not a difficult project. I am assuming that you have a mig wire feed welder and know how to use it. You will also need a carbide cut-off wheel or a sawzall or both.

First of all there are two ways to do the chop. You can either lean the windshield back or you can leave it as is and splice the top. I did the lean method, but in hind sight would not do it again and believe that the top splice method will be less work. I will explain both as the skills are different for each.

As you no doubt already know, the real issue is that as you take metal out of the windshield pillar, the distance from the forward edge of the top to the back of the cab increases and the same pillar needs to be narrowed left to right. Leaning the post back takes up the slack or you can add metal to the top to compensate. You could lean the back of the cab forward, but his would change the appearance of the cab and I have never seen this done. In both cases, you want to start with good door hinges. If you can go to the bottom back part of the door and lift it and move the door, your hinge pins need to be replaced. This is a must or you will have constant difficulty getting an alignment at various steps. If you are going to change the door latches to bear claws, I would also do this only after changing the pins if necessary. I highly recommend bear claws as the existing latch system on the truck is not safe. The truck should be up on jack stands with the bottom of the doors level from front to back and side to side. This is your reference point for cuts to the back of the cab.

The lean method:

1. You need to decide how you want to treat the back window first. If you want to retain the size of the rear window, start by cutting the window frame out of the back as close as you can without disturbing the “roll”. Be sure you cut a nice square cut.
2. Remove both doors, preferably by pulling the pins.
3. Mark the amount of metal you want to take out of the forward post. Use duct tape to wrap around the post and scribe the top and bottom cut locations with an ice pick. Pick a place in the middle of the post where the post changes shape the least. I cut out 3 ½” which was an amount that I found visually appealing. Remember that the more metal you take out will dictate the degree of difficulty. The more you take out, the more compensation is necessary. Carefully cut the section out making sure that the top and bottom cut are absolutely parallel.
4. Scribe a line around the back of the cab which is at the same level as the bottom of the cut used to remove the back window if removed. Carefully measure and level the line so that it is absolutely level all the way around from door post to door post. Cut at this line and remove the top.
5. You are now ready to lean the windshield post back. You will need to make a pie cut at the bottom corner of the windshield post from the inside. A similar cut is made to the inside top corner. The top corner is move forward and the bottom moved back until you eliminate the gap caused by removing the windshield post section. This is a process of successive approximation and it will be helpful if you can have someone work with you to hold the roof section in place to help you estimate your progress. Be careful, you don’t want to take out too much metal or you will have to splice it back in which will weaken the pillar.
6. Now you are ready to estimate the amount of metal to take out of the back of the cab, it will be less than the amount taken out of the forward post. Because the back of the cab is relatively vertical, it is pretty easy to estimate the amount. It is best to take out too little metal and then cut a little more if necessary. I like to use the carbide cut-off wheel on a 4 ½” grinder as it makes a clean cut, is easy to handle and does not bend the metal the way a sawzall does. Make your cuts.
7. Now you can put the roof lid back on and make adjustments in the forward post lean as necessary. Note that you will also have to lean the forward post toward each other as the cab becomes narrower from bottom to top. Once you get the top to fit the bottom sections, carefully tack the top to the bottom with your mig welder. Tack as little as is necessary because you may learn that you need to take it off to correct alignment.
8. Next put the doors back on and make one cut at the middle of the forward door post and one at the Top of the rear door post below the curve. These cuts need to be 90 degrees to the straight sections. Remove the top of the door. If you have done your rear cab alignment carefully, the back of the door should align with the door frame at the back of the cab. If not, you will need to make a pie cut at the bottom of the rear door pillar and align it to the cab. The forward part of the door needs to be pie cut at the bottom forward corner to align it to the forward windshield post.
9. Now you can use the top section of the door removed earlier and align it to the top of the cab door frame. Cut and re-weld as necessary. Be sure that you are getting a consistent gap all the way around the door frame. The second door is done the same as the first. Tack everything in place, do not finish weld until everything is properly aligned.
10. Once everything is aligned check all measurements and use a carpenter level to check out everything. The windshield frame should be the same size from right to left and the lip needs to be adjusted with a dolly to be sure it is flat to the glass.
11. Tack and weld the rear window back in place where you want it.
12. Once you are aligned, take a 40 grit sanding disc and remove all paint, rust etc. from the weld surfaces.
13. You are ready to weld now. Use the lowest heat setting and slow wire feed. Weld short sections allowing heat to dissipate. Particularly on the back of the cab, alternate from left to right so that you can compensate for any changes in the metal caused by heat. If someone can help you, it is nice to have your helper hold a brass or copper heat sink behind the weld surface. This will lessen the chance of burn through and will absorb heat. Go slow. I like to use a soft “EZ grind” wire available from good weld shops.
14. After all welds are done, grind them flat. You are now ready to use body filler to smooth things up.
15. Other considerations. You will want to retain as much of the door window channel support system as you can though it will be moved to new locations inside the door. A difficult section to work with is the forward channel. The existing quarter window system will have to be removed and a channel constructed inside the door to support the new one piece glass. The rear channel moves less, but does need to be relocated a small amount. I used the channel that was at the forward section of the stock glass and made a system of brackets to support the new channel. The angle of the channel is not the same as it was as stock because the glass now needs to be narrower from left to right as caused by the narrower lean of the pillars. This angle needs to be projected down inside the door. I cut a ¼” plywood mock up of the new one piece glass and used this to align the window channels and make the appropriate brackets.

The Splice method:

This method leaves the forward windshield post stock from front to rear though you will have to narrow the distance of the post from left to right. It also makes glass alignment and the new glass channel a little easier to work with.

1. Start by marking scribing a line across the top from left to right at the center of the door section where the roof is flattest. Mark the amount of metal you want to take out of the forward windshield post. Cut the top of the windshield post and across the top all the way through and remove the forward section of the roof.
2. Cut the rear of the cab as described earlier and remove the rear section.
3. Cut the amount you desire out of the forward post.
4. Make struts inside the cab to support the front and rear sections.
5. Tack the front section of the roof to the forward pillars (you will have narrowed the angle left to right with pie cuts in the corners already at the forward pillars).
6. As with the prior method, determine the amount of metal to take out of the rear of the cab and align and tack the rear of the roof to the rear of the cab.
7. Now you will have a gap between the front and rear roof sections. Fill this with an appropriate ribbon of metal. The difficulty with this method is that you will have to fabricate the inner door jamb. I recommend filling the jamb from the inside, welding and filling with body filler as necessary.
8. Install the doors as in the prior method and make your cuts as necessary to the door and align. With this method, there will be less work to do to the door alignment, the process is similar to that described above.
9. You will need to fabricate a small section of the drip rail from some 3/8” steel tubing.

I took the drip rails off completely as I wanted a smooth look. This is a pretty difficult process because the drip rail is the same piece of metal as the top. If you cut off the drip rail, the top needs to be re-welded to the frame. This results in considerably more body work.

I also wanted a 3rd brake light for the rear of the cab. I used a light system from a Ford Taurus Station Wagon. It is made of pot metal and cannot be welded. I used a body weld adhesive obtained from my local paint and body store and glued the system in place from the inside. The installation is clean and worked well.

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Old 12-22-2003, 03:32 PM
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Top chop on FOrd pickup

Do you have any pictures of the chop while you were doing it ??? Id like to see just how you did this. Im good with wire feed and hammer weld but its always better so look at what its SUPPOSED to look like so that you dont have to do it 2 or three times to get it right. if you have some send them to jimsims@earthlink.net, and Ill send you my work in progress for your input....Im going in with out a helmet..!!!!
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Old 02-20-2004, 10:20 AM
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good info
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Old 02-24-2004, 12:24 AM
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KNOWLEDGE BASE.
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Old 02-28-2004, 09:25 AM
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I would also like to see some pictures if you have any. You can send them to me at Fordy8man@aol.com
thanks Fordy8man
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Old 02-28-2004, 08:28 PM
Im trying to have an idea!
 
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post pics? please

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Old 04-13-2005, 07:51 PM
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I also would like to see any pics if you have them. I have a 49 f-1 that I am getting ready to chop. I am gathering all the info that I can, this is all good stuff. I just got a camera too so I will definetly take some, even if i am the guy that tells you how not to do it!
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Old 04-14-2005, 03:22 PM
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My Chop...

Ill send ya a bunch...it really is not bad at all, I got a lot of help from a guy that replied to my questions, a Mr. Humphries....saved me a lot of grief and gave up some great pointers. Number one. Make square cuts...make sure you cut through each pillar at 90 degrees to the length...dont let your saw or your cutting wheel wander....tape the cuts clearly and carefully, and then stay within your tape. I did it backwards to tradition by cutting the door first and then dropping the top down onto the doors....this works on square chops like these old Fords that are very square in shape....dont try this with an old Merc. I found a book on top chops that had a section with pictues using a 50 Ford...very helpfull Ill send the title along in my next e-mail
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