What is the thickest guage steel used on our cars? I'm about to purchase a "nibbler" to do some cutting and they come in three flavors: 14ga., 16ga. & 18ga. I could just go ahead and purchase the largest (14ga.), but the price goes way up with each tool. So...gotta buy only what I need.

I don't think it's over 20ga but 18 should be safe.

I know that it varies from part to part, but I think that most are 20 ga., with some 18 ga. thrown in for a few parts. Multiple thicknesses in a few areas that the engineers felt needed more strength.

--DD

If you are going to make any of your own chassis stiffing kits stuff is 16ga. I bought my first kit then I make my own inner longs myself.

So, a 16ga. cutter should do it for all potential needs?

I have a friend with a fab shop so I end up with getting 16 ga. "drops" from his jobs. We redid a 42 jeep for him with 16ga. and it was ok but the tub had to be twice as heavy as stock. 16 ga is a lot harder to work with. Most body parts are like the guys before said 18 and 20 ga. If you do need to cut two layers I don't think the 14ga nibbler will handle it . I would get the 16 ga as it will be more heavy duty and be easier to use on the 18 ga. and if you need to trim some stiffener stuff you will be able to. I haven't tried them but I think harbor freight had some 18 ga nibblers. I bought some from eastwood and they seem ok. The best tool I have for cutting is the long 4 inch wheel air tool from eastwood. Its expensive but the handiest tool in my shop. After using it for a couple of years I will pay for one again in a heartbeat when it quits. I use it to modify everything, headers, tubing, fiberglass,floorboards, fab mistakes even some aluminium. It's uses are limitless. I like the 1/16 thick wheels.

Charliew

Floorpans are 1.6mm, which is about 16ga.

If you are talking about the passenger floor, mine are media blasted with no paint, tar, etc and measure slightly less than 18g. So taking into account some loss of material due to media blasting, I am pretty sure they are 18g.

The metal that makes up the bulkhead between the engine in passenger compartment and the longitudinals also measure 18g after media blasting. I have not measured them, but I suspect the exterior body panels (fenders, etc.) an a number of other non-structural items are 20g.

I just didn't want anyone to go out and buy 16g if they are doing a floor repair and are wanting to match up exactly.

Richard

"gauge" is such a horrible system of measurement. It is based on weight rather
than thickness. So the thickness of a given "gauge" is different depending
on the metal. ie 16 gauge steel vs stainless steel galvanized steel,
vs aluminum are all different thicknesses.
(I believe this goes back to how it was taxed years ago)

To make matters even more complicated, the Imperial system of measurement
is so painfully crude, there is alot of of folks tend to round and say
"about" this size.
(Metric is much better - but the US hasn't decided it important enough to mandate it)

Making it even more complicated, some panels actually do come in metric
thicknesses, but because the US market is so used to "gauge" they back
convert it from mm to gauge and sometimes screwup the conversion
or have to round to get one of those "about" gauge sizes.
Some metal will actually come marked with both metric thicknesses
and gauge.

The best bet is to get out your calipers and actually measure it.
Since our cars were made in Germany, (one of the evil metric system users),
the metal is based on metric thicknesses. Much of what is in the car is actually
1 mm. This doesn't map directly to a US "gauge".

It works about to be "about" 19 gauge (steel of course)
which isn't one of those normal US sizes. 18 gauge is probably
the closest without getting something thinner.

Here are some other posts related to this:

Metal question ?, What gauge metal ?

Steel Gauge thickness of panels


--- bill

I've measured the floorpan steel with a digital caliper, and it is 1.6mm. I don't know what that equates to in cubits, dog years, or whatever, but it is 1.6mm. Without paint, or tar.

Interesting. What year is your car? Maybe they changed thickness of the floor at some point? Mine is a 1972. I do find it hard to measure something that thin with a caliper. With my micrometer a few floor measurements range from .0425" to .0460". 18g is .0478".

I also agree with the post above that they probably using a metric guage. And that 18g and 20g non-galv are the closest fits.