S30 Sheet Metal - Body and Chassis Panel Thicknesses

[Namerow]

On 4/12/2020 at 1:48 PM, CanTechZ said:

Measured .030" (.76mm). Most likely 0.8mm thick sheet metal.

Thanks for the additional efforts.  However, it's just hard for me to believe that the factory used a thinner sheet for floor pans than what they seem to have used for body panels like the rear quarters.  At least, that's what your measurements are saying (i.e. 1.1mm for the rear quarter panel vs. 0.8mm for the floor pan). 

It's worth noting that the difference between 1.1mm and 0.8mm is just .012" (sorry for the switch from metric to inches, but most of us understand tolerances best when they're in thousandths of an inch rather than tenths or hundredths of a millimeter).  How thick is the factory primer and paint?  Or maybe that's an aftermarket paint job on your rear quarter?

We're left two possibilities to ponder: 

1.  The factory floor pans really are made of thinner sheet than the factory body panels.

or,

2. One (or maybe both) of your measurements (floor pan vs quarter panel) doesn't represent 'reality'.  Maybe your quarter panel measurement was too high because the metal wasn't bare?  Or maybe your floor pan measurement is too low because you accidentally abraded away some of the metal in the effort to get rid of the paint?  Maybe both?  In inches, you have the rear quarter panel and front fender measured at an average of 1.1mm, or 0.043".  As I mentioned earlier in this thread, that would equate to a thinnish 18-gauge.   Your new 0.8mm measurement for the floor pan works out to 0.031" which would suggest really thin 20-gauge is right in the middle of the spec range for 22-gauge..

FWIW, I continue to like 1.0mm (0.039") for the factory floors and body panels because: a) 0.8mm sounds too thin, and; b)  1.1mm seems like an illogical (off-spec) choice that would have struck the Nissan engineers as being not only more expensive to buy from the mill but also adding 10% more weight than 1.0mm and requiring higher stamping forces.

That said, it's interesting to see ConverTT's report that the Klokkerholm rear quarter repair panels are made from 22 gauge!

As always, comments welcomed 

Edited April 15, 2020 by Namerow
a few numerical corrections... and then an important correction to my gauge interpretation of 0.8mm

[CanTechZ]

You make valid points, when I removed paint for the previous floor pan measurement I did my best to not remove any metal.

I decided to re-measured my front fenders and rear quarters. This time I used a micrometer and took all measurements thru the opening for the side marker light openings. First here is a bit of history on my car, the LH rear quarter was replaced in 1979 with an OEM original part number 78101-E4600 (correct for up to 12/70) and was painted 918 during that repair. In 1982 I replaced the RH quarter panel and both front fenders and then had the whole car repainted in a GM metallic Ontario orange. In 1982 I was still able to get OEM parts from my local dealership but for the RH rear quarter I was only able get p/n 78101-E8800 which applies for 1/71 on, and had a hole for a side vent that I had welded closed as my car is a 7/70. So the LH rear quarter has one more coat of paint than the rest of the car. Here are the new measurements I recorded through the side marker light openings, including paint:

LH Front - .041" (1.04mm)

RH Front - .040" (1.02mm)

LH Rear - .041" (1.04mm)

RH Rear - .039" (.99mm)

Here is a measurement after carefully removing paint on the LF front. Outside seams to have one top coat, a reddish primer coat and original factory greenish gray primer, the inside seems to have what looks similar plus a black primer? Measuring on bare metal I recorded this:

LF Front Bare - .031" (.79mm)

I'm now thinking that both the body panels and floor pan were produced using 0.8mm thick steel.

[Namerow]

Meticulous measurements, backed up by supporting info re panel originality and paint application, so pretty hard to argue with.  I am inclined to agree, then, with your conclusion that the factory panels appear to have been made from 0.8mm sheet.  That sits right in the middle of the spec range for 22-gauge.  How do we reconcile this with @ConVerTT's values of 20-gauge for the door skins?

[ConVerTT]

I am not prepared to accept that conclusion at all without further investigation ....

I can offer the following:  I have several NOS parts, never installed, and in factory primer, that I will measure this weekend.  (Fenders, rear quarter, inner rocker, inner wheelhouse that I will re-measure and post here.  I also still have a door skin that I just removed from a 72 as well.

I can't do it until the weekend though so please be patient ....

 

[CanTechZ]

@Namerow When I strip my doors I will try to get measurements, I also have doors from a 12/70 parts car in my shed that I will try to get to and measure.

@ConVerTT I respect your position and look forward to seeing your findings, thanks in advance.

Edited April 15, 2020 by CanTechZ

[CanTechZ]

I removed the chrome trim from my doors and found a spot to measure the door skin thickness. I measured .036" (.91mm) with paint, and .032" (.81mm) with paint removed.

 

[ConVerTT]

Multiple measurements from 72 door - 46081 built 9/71.  The door has been chemically stripped and sanded with the Contour SCT with 120 grit....

 

Zeroed ...

 

Window edge ...
 

Mid-door

 

More mid door on the edge of thr cut section ...

 

 

[Namerow]

So:  Two sets of well-executed/well-documented measurements with different results.  They aren't quite apples and apples, though.  CanTechZ has measured Series 1 front/rear fenders and floors and gets a pretty consistent 0.8mm result..  ConverTT has measured Series 2 door skins and gets an equally consistent result of 1.0mm.

Others have reported 0.032" >> 0.8mm) for a couple of other panels  : jfa.series1 for the front inner fender apron (i.e. engine compartment side wall), and me for my Series 1 front valence panel.

I have a theory (untested and unproven so far)...

ConverTT's photo of his Series 2 door where the outer skin has been cut off provides a great view of the side impact bar (and I use that term with some reservatyion when it comes to the piece used in the S30's doors ).  As near as I can tell, that Series 2 impact bar looks exactly the same as the ones in the doors of my Series 1 (SN in the 3500's).  And yet, it was always my understanding that those side impact bars weren't part of the early cars.  Or maybe that was only the case for the early early cars?  Or maybe my car is wearing replacement doors from a Series 2?   Note that the online Parts Manual shows a change in part numbers for the two doors as of October 1971... although that doesn't really explain whether anything changed in the design.

My theory, then:  Is it possible that Nissan neither added nor changed the size of the side impact bars, but instead simply increased the thickness of both the outer door skins (and maybe the bars, too) from 0.8mm to 1.0mm?   There would be a certain logic to this, because Nissan probably could have left their tooling unchanged and just changed the thickness of the panel stock.

@ConVerTT  Can you please take some measurements on a rear quarter at the opening for the side marker light?

@CanTechZ  Can you please take a measurement on one (or both) of your doors?  Say, at the opening for the door handle?  failing that, maybe on the lip the mounts the upper chrome moulding?  If time permits, I'll do the same later with the doors on my car later today (I want to make a start on my income tax return this afternoon  ).

[ConVerTT]

Also from series 1 - 05677 ....

 

Edited April 19, 2020 by ConVerTT

[ConVerTT]

16 minutes ago, Namerow said:

.

ConverTT's photo of his Series 2 door where the outer skin has been cut off provides a great view of the side impact bar (and I use that term with some reservatyion when it comes to the piece used in the S30's doors ).  As near as I can tell, that Series 2 impact bar looks exactly the same as the ones in the doors of my Series 1 (SN in the 3500's).  And yet, it was always my understanding that those side impact bars weren't part of the early cars.  Or maybe that was only the case for the early early cars?  Or maybe my car is wearing replacement doors from a Series 2?   Note that the online Parts Manual shows a change in part numbers for the two doors as of October 1971... although that doesn't really explain whether anything changed in the design

My 72 was built in Sep 71 ...

Edited April 19, 2020 by ConVerTT

[ConVerTT]

I can take some move measurements on my series 1.  Need to wait for a rainy day - she's napping ....

[Namerow]

Excellent!  Nice parts storage rack, BTW.