Theoretical

[1984RESTOMOD]

Say a feller wanted to swap headliner/roof assembly from one cab to another. Where would be the best spot on the pillars to cut?

 

[JoshT]

I'm no expert here, but I'll throw in my 2 cent.

Best would be to separate the roof skin layers and build it back together like the factory did. That would give the strongest result.

If you're going to be cutting the pillars, I don't think it much matters. Regardless if where you cut them it will create a seam and weaken the assembly. IMO most important is to get the cuts matched between the donor and receipent so that everything matches up properly when it goes back together. Unless of course you want to make a chop top, in which case you're going to be doing a bunch of cutting, sectioning, and splicing to get it right.

 

[lil_Blue_Ford]

If you are doing a chop top or a removeable hard top, you are going to want a cage and tie the pillars to the cage as high up as possible. Cutting pillars reduces strength from day 1.

 

[JoshT]

Agreed, but if you're doing as @lil_Blue_Ford suggests, I'll add to it.

Unless you are doing a hot rod style chop top, aka lowering the roof, I wouldn't cut the A pillar at all. Instead cut across the roof and keep the window surround intact. Still add a roll cage as he suggested.

 

[lil_Blue_Ford]

Agreed, but if you're doing as @lil_Blue_Ford suggests, I'll add to it.

Unless you are doing a hot rod style chop top, aka lowering the roof, I wouldn't cut the A pillar at all. Instead cut across the roof and keep the window surround intact. Still add a roll cage as he suggested.

Good point, if you want to remove all the way to the windshield, trim the roof out but leave a rim all the way around connecting both A and B pillars, that leaves a place for your doors to seal all the way around. If you’ve ever been around a Jeep “Wranger” style (CJ, YJ, TJ, JK, etc), they have no real seal around the top of the doors unless they have a hard top. It’s not an ideal situation. My Choptop BII retains the roof over the front seats and is only open in the back, much like a full size Bronco with the top off. It’s nice to have a full door that seals all the way around.

I have considered putting a sunroof in the remaining roof of the Choptop…

 

[1984RESTOMOD]

Thanks for all the input guys - I got a mig/flux welder for xmas so it's finally time to tackle this. My donor cab came without the rear glass installed so it rusted around the top rear window lip and also the headliner on the passenger has small spot rust thru so headliner replacement is a must. I'll post some pics later for better explanation.

 

[1984RESTOMOD]

Headliner (note thru rust around driver/passenger door and rear window)

passenger

driver

rear window

Donor piece

also this from mouse nest but I’ve got a donor piece for it also. Still unsure how exactly I’ll go about it but I’ve got some time to work on it coming up so I’ll keep posted.

 

[1984RESTOMOD]

Can’t tell if this is sketch or not. Shell is 150 pounds at best.

 

[MT_PLS]

I would flip the 2x4s on their side and then tie them together with another board. That would remove the bow in the boards and you'll be less likely to have sagging issues where the boards could break.

 

[alwaysFlOoReD]

View attachment 122202
Can’t tell if this is sketch or not. Shell is 150 pounds at best.

It hasn't broken yet...
Slide another 2x beside the others.
Basically you have 37.5lbs on each of 2 spots on each 2x4.
WAG; I doubt a static load is going to do much to those 2x4 as long as there isn't a defect, like a knot.

 

[Brain75]

If you want to go full on Safety Sally and calculate your dead load and figure out your load per sq ft and and... then look up on a "span table" as carpenters call it and find what your rated load for your lumber should be... I think just off the top of my head #2 fir 2x4 are 10#/ft^2 dead load and half that live load - 100% of yours is dead load... so if you wanted it to last up there forever and ever then yeah you need much more lumber spaced evenly.

Doubling up 2x4's (as f they were 4x4's) adds 25% capacity not double like you would think.

 

[alwaysFlOoReD]

I weigh 245 lbs. I walk across spruce/pine 14' 2x12 all the time. I wouldn't hesitate to walk across a 8' 2x8 if it was knot free. I don't think those 2x4s are going to collapse...
PS; I test my planks by setting one end on a saw horse and jumping up and down on it. I've had one plank break under me in 40 years...scared the hell out of me but not hurt much. I did siding and exterior renovations...
PPS; I'm definitely not OSHA compliant most times...lol

 

[Brain75]

I think you'll find 2x4 is a lot lot less rated than 2x6 which is a lot less than 2x8, etc. every time you thicken it up the rating goes up quite a bit... more then even just linearly.

FWIW, I never said his 2x4's are gonna collapse tomorrow, I said if he is doing it long long term I would want to do more than just a couple 2x4's at that length (just eyeballing his length and guessing)

Span tables really aren't that hard to use. They saved my ass from buying a bad house. (someone had done a beautiful sun room add on by enclosing their porch and used 2x8's which is fine 300 days a year, but were not enough to handle the snow load we get here - guess what happened 2 years later when I passed on the house when we got 6' of snow.)
I asked them to fix the add on correctly, they refused, I walked away from the purchase.

Joist Span Tables

Joist Span Tables - Use these tables to determine maximum span of ceiling joists.

www.mycarpentry.com

 

[Brain75]

And I'm not being pissy or know it all, I am saying just like that roof (which lasted 3 years before I looked at it and 2 more after), over-loading lumber will hold for a period of time but some day it will fail... rather not see it fail and smash into the truck.
The span table is grossly over-conservative, they are regulated by industry to prevent loss of life, so you can definitely go past - just be aware of how much damage you are willing to risk and cost you want to put in.

 

[alwaysFlOoReD]

I think you'll find 2x4 is a lot lot less rated than 2x6 which is a lot less than 2x8, etc. every time you thicken it up the rating goes up quite a bit... more then even just linearly.

FWIW, I never said his 2x4's are gonna collapse tomorrow, I said if he is doing it long long term I would want to do more than just a couple 2x4's at that length (just eyeballing his length and guessing)

Span tables really aren't that hard to use. They saved my ass from buying a bad house. (someone had done a beautiful sun room add on by enclosing their porch and used 2x8's which is fine 300 days a year, but were not enough to handle the snow load we get here - guess what happened 2 years later when I passed on the house when we got 6' of snow.)
I asked them to fix the add on correctly, they refused, I walked away from the purchase.

Joist Span Tables

Joist Span Tables - Use these tables to determine maximum span of ceiling joists.

www.mycarpentry.com

All true enough. And I don't want to be busting balls either. A good discussion is always welcome, especially with facts! I didn't look at the span tables so I'm making the assumption that when they are calculated they are stood on edge? So the 1.5" edge is parallel to the ground and the long side is at a 90° angle to the ground?