And nor were they ever meant to be equal. Either way the several I've put together were done with a 7/16" wrench without an issue.
Hope I'm not boring people with the obvious, but:
A 7/16" is too big, swings more before it connects, and is more likely to come off the fastener while you are straining to hold fiddly parts together while they are trying to separate. This is what happened to me. I wouldn't have gone to get a 10mm if things had been going smoothly with 7/16".
You may not don't know this, but wrenches from different companies vary in how closely they match nominal size. Your 7/16" is not necessarily going to grip a 10mm as poorly as someone else's. Your experience isn't universal. I don't think you should assume I tried using a 7/16", found it worked perfectly, and then went to the trouble of putting the parts down and getting a 10mm.
It's pretty obvious that a company that uses 10mm fasteners should call for the correct wrench. There is no reasonable explanation for calling for a wrench that doesn't fit properly and causes problems. Nominally, the difference between a 10mm and a 7/16" is bigger than the difference between 10mm and 11mm, and nobody would make a smoker with 10mm nuts and call for an 11mm wrench. Well, maybe Weber would. Maybe it's their way of downplaying the China connection.
The instructions clearly show they go on the outside between the body and the part being attached.
That's wrong. The small black washers are incorrectly shown as larger than the big steel ones, and the instructions, being cartoons, contain no description of their purpose. You can see it in the picture you posted.
FYI, Virtual Weber Bullet's assembly video, the only one I could find, has errors, including showing the wrong number of fiber washers. It's 15 years old. Maybe the smokers were different during the Obama administration. It omits the fiber washers on the leg screw holes.
I owe Weber an apology for thinking they were behind that video. Turns out it's a channel started by a fan. But Weber participates in his forum, and its reps send people to Virtual Weber Bullet for help.
I didn't mention the burrs inside the M6 nuts, but I guess I will now. Those can cause cross-threading if they are not handled carefully. Because of the burrs, it was impossible to get all the nuts onto the screws by hand. The smoker is part Chinese. They must be using Chinese nuts. I had to turn several nuts around and run the screws into their better sides. Fortunately, I didn't have to use taps.
