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S30 Sheet Metal - Body and Chassis Panel Thicknesses

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On 4/6/2020 at 10:33 AM, CanTechZ said:

Here are a few references regarding Japanese cold finished sheet steel thicknesses and tolerances.

JFE Tolerance Table.JPG

Japanese Sheet Metal Thicknesses [US bureau of standards]+Table 37.jpg

JFE CR Steel Sheet [Japan].pdf 1.82 MB · 0 downloads

I like the second table, esp. the fact that the standard dates back to 1922 and therefore encompasses the period when the S30 was being built.  It indicates that the 1.1mm thickness offered by contemporary supplier Parker Steel (see my earlier entry in this thread) is not really relevant to the sheet used for the S30 body panels.  It looks, instead, like 1.2mm (0.0472") would be closer to the truth.

The JFE brochure provides some interesting insights into the cross-section of sheet steels available to modern-day automotive/manufacturing engineers for body pressings.  With techniques like hydroforming and materials like high-strength and ultra-high-strength now available, things are a lot different than they were back in 1969. 

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Posted (edited)
1 hour ago, Namerow said:

I like the second table, esp. the fact that the standard dates back to 1922 and therefore encompasses the period when the S30 was being built.  It indicates that the 1.1mm thickness offered by contemporary supplier Parker Steel (see my earlier entry in this thread) is not really relevant to the sheet used for the S30 body panels.  It looks, instead, like 1.2mm (0.0472") would be closer to the truth.

The JFE brochure provides some interesting insights into the cross-section of sheet steels available to modern-day automotive/manufacturing engineers for body pressings.  With techniques like hydroforming and materials like high-strength and ultra-high-strength now available, things are a lot different than they were back in 1969. 

Yes, I was also happy to find that table with available standard thicknesses from the period. With enough volume and modern methods manufacturers today definitely have more options. I plan to remove my seats on the long weekend so I will have better access to measure again. I will report back with my findings.

Edited by CanTechZ

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Posted (edited)

How about these pieces from the front wheel wells?  Must be 12 gauge, and some of the thickest sheet metal I have yet encountered on my series 1.   Anyone know of where to get these prefabbed, or an easy way to make them?  I cant bend/form that thickness...

IMG_2623[1].JPG

IMG_2621[1].JPG

Edited by AZStory

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In the pic it looks like all the perimeter bends are usable. I'd consider cutting the bad (missing) parts out, leaving all the bends that are usable, and welding in inserts.

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2 hours ago, Mark Maras said:

In the pic it looks like all the perimeter bends are usable. I'd consider cutting the bad (missing) parts out, leaving all the bends that are usable, and welding in inserts.

It's true.  Outside diameter is good metal. Unfortunately its where the complex bends are that's rusty. You can see the lines where I started to draw out my cuts, but I'd really prefer to buy two if I could, both sites are like this.  I'm a little surprised that this isn't more of a documented issue for other folks too...maybe I got lucky.  

Not trying to hijack this thread though. Wanted to share this piece's thickness. 

 

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9 hours ago, AZStory said:

Anyone know of where to get these prefabbed, or an easy way to make them? 

first cut of the "floor"part, you have to weld that one or a new flat piece onto it later.

As the piece of steel is only 2 mm you could easely make one on a piece of oak wood. Make a piece were the old piece fits in exactly.  

a bit of woodworking and some hammerin.  like this for example..

(This is a piece for a 280zx frontfender, made out of 1mm steel, some welding needed on the edge low right and a longer weld in the left lower layd part.)

20191206_150232.jpg

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8 hours ago, AZStory said:

I'm a little surprised that this isn't more of a documented issue for other folks too...maybe I got lucky.  

One of the build threads on this site provided a step-by-step fabrication procedure for this exact piece.  Unfortunately, I don't remember which thread it was.  Maybe someone else will.  It basically made up the piece in the form of a set of flat panels.  Only straight-line bends and cuts were used.  He had to weld in filler pieces to create the floor and the front and rear vertical walls of the pocket. If you think of how you could create the piece using cardboard and tape, you'll get the idea. 

It's too bad that the answer to this kind of question has to rely on the memory of other readers and contributors.  One of the weaknesses of sites like CZCC is that the search tool depends on the words that the tread's author uses to describe their work.  For example, what would you call this particular piece?  One person might call it a 'doubler'.  Another might call it a 'reinforcement' or an 'insert'.  There's also the distinct possibility that the author of the build thread that I'm thinking of may have described his procedure without ever giving the piece a name.

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Posted (edited)
4 hours ago, dutchzcarguy said:

first cut of the "floor"part, you have to weld that one or a new flat piece onto it later.

As the piece of steel is only 2 mm you could easely make one on a piece of oak wood. Make a piece were the old piece fits in exactly.  

a bit of woodworking and some hammerin.  like this for example..

(This is a piece for a 280zx frontfender, made out of 1mm steel, some welding needed on the edge low right and a longer weld in the left lower layd part.)

 

I really like this idea and hadn't thought to make a wood form to hammer over.  Thanks for sharing this.

Edited by AZStory
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Posted (edited)
14 hours ago, AZStory said:

How about these pieces from the front wheel wells?  Must be 12 gauge, and some of the thickest sheet metal I have yet encountered on my series 1.   Anyone know of where to get these prefabbed, or an easy way to make them?  I cant bend/form that thickness...

IMG_2623[1].JPG

IMG_2621[1].JPG

Calling @wheee!.  Search his build thread.  He built new ones and did a step by step.  I have built some using a similar process too here, middle of Page 1....

 

Edited by ConVerTT
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Ya, I have a page or two on that in my build thread somewhere.


Sent from my iPhone using Tapatalk

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20 hours ago, AZStory said:

I really like this idea and hadn't thought to make a wood form to hammer over. 

And use a piece of metal shaped like a (side) banana peel.. sort of..  why? The upper piece will bend as you hit it with a big hammer. And make it square after you made the big dent.. think about it, you'll get the picture. (make the edges with a chisel (for steel obviously… my translator could give no good word for it but i mean the chisel that you use for breaking stone walls and can be used to make a nice edge in sheet metal.)

Also use some clamps and then make the bend.. or whatever you need to do.

20191206_143010 (1).jpg

 

Btw, i think it's a good idea to make a special topic on these things, or make a list with where one can find certain "make it yourself" substitute parts..

Back to GAUGE's and inches and millimeters!!  ?

Edited by dutchzcarguy
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Here’s some pics:

5F0C2898-1F07-4BA1-9433-1686ABE94318.thumb.jpeg.880863a142028c60f65456626c04c508.jpeg

6E081F8D-9096-4E45-A5BB-03161C41234F.thumb.jpeg.7a3cfdbce9f74d34fe215ce28c6e3c55.jpeg

C9B9E5DD-AB18-47E7-8B26-123F2D1D41D1.thumb.jpeg.8e63158c22008ac770e8b970c0b092f2.jpeg

424FA043-6C4F-439F-9E27-A2E3A53354E0.thumb.jpeg.85a423fa09f3d19de6b7c1a9a84e7c77.jpeg

42AD3362-FAB8-4014-9432-33E9E118762F.thumb.jpeg.bb18b4837ac9c6faeb3217e07995c641.jpeg

82385578-2026-4932-9AA7-46E2F537C4EF.thumb.jpeg.d60399039f6b44713e06269b4e74ea04.jpeg

E52748A8-0F1E-4C58-B322-94E0ED77B110.thumb.jpeg.0c798121c58a30be0697e204d1ef6f12.jpeg

DC4A73E8-390E-436B-9B30-81CFCA14EFB4.thumb.jpeg.01ef1b485d1a8c2c4db8eba3d442b1e0.jpeg

95E4A0CA-0FCC-4050-A91E-72106E828D5F.thumb.jpeg.fa18dcaab8353428b6dd546ad7ddbfed.jpeg

 

Edited by wheee!
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Truly harrowing how such a thick piece of steel can be eaten through by rust.  I suppose it has to do with its location (up front and down low) and the moisture-retaining space created in the gap between it and the inner fender apron.  Maybe residual warmth from the engine after being parked helped out too.  There must have been a lot of salt-belt Z's that were just one pothole-in-the-middle-a-hard-corner away from having the front crossmember part company with the frame rails.  On a similar note, I remember back in the day hearing a story about a Z in Montreal that broke in half after a minor fender-bender ?

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On 4/6/2020 at 9:36 AM, grannyknot said:

But just as an aside, my American Standard Gauge gauge reads 20ga as .032", 19ga as .036", 18ga as .040", 17ga as .045", 16ga as .051 all of which are different from the table you posted

Sorry, I missed this earlier note from @grannyknot.  Wish I could remember where I got my gauge chart from (it dates back several years).  The discrepancy between GK's values and those from my chart are large, so I just went looking for another source and came up with this one from machinemfg.com (website for a machine manufacturer).  I wouldn't call it a definitive source, but the values coincide with the chart that I posted...

www.machinemfg.com/sheet-metal-gauge-sizes-chart-inch-mm/#Sheet_metal_GAUGE_thickness_chart 

So then I searched for a chart for the American Wire Gauge (AWG) and discovered that its values agree with GK's...

www.powerstream.com/Wire_Size.htm

None of my sources are definitive.  If someone wants to post the tables from an accepted engineering reference like Shigley's, that would resolve the issue once and for all (I never could afford that book when I was in school and just used my employer's copy after I got out into the workforce).

It appears, though, that we've tripped over yet another facet of wacky world of 'gauge' measurements  --  that is, that gauges have different 'thickness' values, depending on whether you're looking a wire diameter vs. sheet thickness.    Another vote in favor of metric.

Edited by Namerow
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New of my chart, updated with most recent contributions...

Panel Location

Measured Thickness
(t)

Source

Gauge
(derived from ‘t’)

Gauge
(reported)

Source

Front Apron
(engine compartment)

0.032”

Jfa.series1

20

20

Grannyknot

Tabco repair panels
(all)

 

 

 

20

Manufacturer
ConverTT

Klokkerholm repair panels
(rear quarter)

 

 

 

22

ConverTT

Thick-gauge panels & pieces
(which ones?)

 

 

 

18

2manyZs
kmack

Lower Front Frame Rail
(OE)

0.050”

Carl Beck

18

18

ConverTT

Lower Front Frame Rail
(ZeddFindings)

0.062”

Namerow

16

 

 

Lower Front Frame Rail -
Reinforcement plate (‘pocket’) at front crossmember mounting point

0.0747

AZStory

14

 

 

Upper Front Frame Rail
(‘horn’)

0.054”

Carl Beck

~ 16

 

 

Front Valence Panel

0.032”

Namerow

~ 20

 

 

Front Crossmember

0.076”

Namerow

~ 14

 

 

Door – outer skin

 

 

 

20

ConverTT

Inner Rocker Panel

 

 

 

18

ConverTT

Radiator Support

 

 

 

18 + 20

ConverTT

Floor Pan (OE)

0.044”

CanTechZ

~ 18

 

 

Floor Pan (ZCar Depot)

0.045”

vendor

~ 18

 

 

Floor Pan Bottom Rail
(ZCar Depot)

0.060”

vendor

16

 

 

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17 hours ago, Namerow said:

we've tripped over yet another facet of wacky world of 'gauge' measurements  --  that is, that gauges have different 'thickness' values, depending on whether you're looking a wire diameter vs. sheet thickness.    Another vote in favor of metric.

It's like the (english) imperial gallon (4,546 Liter.)  and the (american) US Gallon ( about 3,785 liter.) all over!!

1 Imperial gallon = 1.20095042 US gallon = 4.54609188 Liters

And when someone starts talking about Pints, ? i always have to laugh about it, yeah do me a Pint.. :beer:

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Not that the metric system doesn't have its own moments.  Consider the standard for determining the metre length unit. 

The basic unit of length in the metric system; it was originally planned so that the circumference of the Earth would be measured at about forty million meters. A meter is 39.37 inches. Today, the meter is defined to be the distance light travels in 1 / 299,792,458 seconds.

Based in science? Yes.  Intuitive?  Not hardly.  I like the definition of the kilogram better:

The kilogram is almost exactly the mass of one litre of water.

Consider, by contrast, the definition of the inch:

The old English ynce was defined by King David I of Scotland about 1150 as the breadth of a man’s thumb at the base of the nail. To help maintain consistency of the unit, the measure was usually achieved by adding the thumb breadth of three men—one small, one medium, and one large—and then dividing the figure by three. During the reign of King Edward II, in the early 14th century, the inch was defined as “three grains of barley, dry and round, placed end to end lengthwise.” At various times the inch has also been defined as the combined lengths of 12 poppyseeds. 

Makes one pause when considering the implications of having a 427 cubic inch engine in your car.?

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On 4/10/2020 at 10:11 AM, Namerow said:

New of my chart, updated with most recent contributions...

Panel Location

Measured Thickness
(t)

Source

Gauge
(derived from ‘t’)

Gauge
(reported)

Source

Front Apron
(engine compartment)

0.032”

Jfa.series1

20

20

Grannyknot

Tabco repair panels
(all)

 

 

 

20

Manufacturer
ConverTT

Klokkerholm repair panels
(rear quarter)

 

 

 

22

ConverTT

Thick-gauge panels & pieces
(which ones?)

 

 

 

18

2manyZs
kmack

Lower Front Frame Rail
(OE)

0.050”

Carl Beck

18

18

ConverTT

Lower Front Frame Rail
(ZeddFindings)

0.062”

Namerow

16

 

 

Lower Front Frame Rail -
Reinforcement plate (‘pocket’) at front crossmember mounting point

0.0747

AZStory

14

 

 

Upper Front Frame Rail
(‘horn’)

0.054”

Carl Beck

~ 16

 

 

Front Valence Panel

0.032”

Namerow

~ 20

 

 

Front Crossmember

0.076”

Namerow

~ 14

 

 

Door – outer skin

 

 

 

20

ConverTT

Inner Rocker Panel

 

 

 

18

ConverTT

Radiator Support

 

 

 

18 + 20

ConverTT

Floor Pan (OE)

0.044”

CanTechZ

~ 18

 

 

Floor Pan (ZCar Depot)

0.045”

vendor

~ 18

 

 

Floor Pan Bottom Rail
(ZCar Depot)

0.060”

vendor

16

 

 

I'd just like to clarify that in my photo, my thickness gauge would not clear the sheetmetal on the "pocket" piece at 14g.  I think it's 12g sheetmetal. 

Edited by AZStory

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7 hours ago, AZStory said:

I'd just like to clarify that in my photo, my thickness gauge would not clear the sheetmetal on the "pocket" piece at 14g.  I think it's 12g sheetmetal. 

Point noted.  However, 14-gauge sheet can be anywhere from 0.0697" to 0.0797" so your measuring gauge (sized at the median thickness of 0.0747") could register a 'no-go' even though the piece actually was made from "14-gauge" steel.

More likely, however, is that this piece (like most of the other steel used in the S30)  was made from sheet steel rolled to the metric standard by a Japanese steel mill.  It seems very like that this doubler/reinforcement piece was stamped from 2.0mm stock (which nominally converts to 0.079" and would therefore likely register as 'too thick' for your measurement gauge's '14-gge/0.0747"' slot).

Note also that 12-gauge is a big jump up in thickness from 14-gauge...  0.1046" vs. 0.0747", so an increase of 0.0299"... which is almost 1/32".  From your picture, it doesn't look like your there's a mismatch of 0.03" between the S30 part and the 14-gge slot in your measurement gauge.  It also looks like your 12-gauge slot would be way too big...

IMG_2621[1].JPG

All things considered, then, I like "14-gauge" for this part because it's very close* to what is most likely the real truth -- which I think is 2.0mm.
(* 2.0mm/0.0787" vs. 14-gge/0.0747", so within 5% using the nominal design thicknesses).

My purpose in starting this thread was to create a reference chart for selecting the right** sheet thickness to use for panel repairs.  Since very few of us (in Canada and the US) have convenient access to metric-standard sheet steel, the best guidance for repair panel thickness comes in the form of 'gauge'.  I suppose I could add a "mm" column, but that would confuse the heck out of everyone.
(**  Let me qualify my use of the word 'right' by adding that there's sometimes an incentive for using a thicker steel than the factory did.  A good and common example is the bottom rail ('support') for the floor pans, where some owners choose to go with a thicker-than-factory steel and go full-length in an effort to better tie the front and rear sections of the 'chassis' rails together.)

Edited by Namerow
new comment added

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Table updated to show revised (refined) measurement for the lower front frame rail reinforcement piece...

Panel Location

Measured Thickness
(t)

Source

Gauge
(derived from ‘t’)

Gauge
(reported)

Source

Front Apron
(engine compartment)

0.032”

Jfa.series1

20

20

Grannyknot

Tabco repair panels
(all)

 

 

 

20

Manufacturer
ConverTT

Klokkerholm repair panels
(rear quarter)

 

 

 

22

ConverTT

Thick-gauge panels & pieces
(which ones?)

 

 

 

18

2manyZs
kmack

Lower Front Frame Rail
(OE)

0.050”

Carl Beck

18

18

ConverTT

Lower Front Frame Rail
(ZeddFindings)

0.062”

Namerow

16

 

 

Lower Front Frame Rail -
Reinforcement plate (‘pocket’) at front crossmember mounting point

0.0787”
(2.0mm)

AZStory

~ 14

 

 

Upper Front Frame Rail
(‘horn’)

0.054”

Carl Beck

~ 16

 

 

Front Valence Panel

0.032”

Namerow

~ 20

 

 

Front Crossmember

0.076”

Namerow

~ 14

 

 

Door – outer skin

 

 

 

20

ConverTT

Inner Rocker Panel

 

 

 

18

ConverTT

Radiator Support

 

 

 

18 + 20

ConverTT

Floor Pan (OE)

0.044”

CanTechZ

~ 18

 

 

Floor Pan (ZCar Depot)

0.045”

vendor

~ 18

 

 

Floor Pan Bottom Rail
(ZCar Depot)

0.060”

vendor

16

 

 

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This morning I re-measured my floor pan thickness with seats out and better light, the new reading was .040" (1.02mm). However with the better light I noticed that there was still original paint on the under side that was quite thick. After scraping off some paint I measured again and the new reading was .0315" which equals .800mm. My car is a 7-70 production date.

1970 floor pan thk HLS30-06521.jpg

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Here is another floor pan measurement, this time for the mid floor section behind the left seat. Measured .030" (.76mm). Most likely 0.8mm thick sheet metal. Again about the only good purpose for a rust hole.

1970 floor pan-mid thk HLS30-06521.jpg

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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 :wacko:

image.png

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

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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.

20200413_140605.jpg

20200413_112852.jpg

20200413_140249.jpg

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