large and small box calculations

hi, maybe this has been answered but i looked all over the forum and the admin and cant find the answer.
what calculates/determines what is a small and a large box?? where is the threshold?
we are using USPS shipping module.

also, if i want to limit one attributes shipping options is there a way to do that? i have very small sample sizes that can go in an envelope. the sample size is an attribute of the product.

thanks in advance,
MM

USPS determines this and this is from their site: USPS Site

Package

Use “Package” when the length plus girth (the distance around the thickest part) of a package equals 84 inches or less. Most packages fit within this category.

Large Package

Use for packages when the length plus girth (the distance around the thickest part) of a package is more than 84 inches but not more than 108 inches. For packages over 108 inches but not more 130 inches, see oversized package.

What determines a large package for zone rate shipping?

This is all fine and dandy that USPS figures that information based on LxWxH, however nothing in Zen-cart tells USPS those dimensions.

Everyone who orders on my site is getting charged a lot less that what it would actually cost me to ship, as such I have to limit what shipping options I can safely put on my website.

Is there a shipping module that takes into consideration shipment dimensions?

I just ran into this issue, as well. A customer ordered a product that ships in an 11 x 11 x 16 box and I'm losing about $5 on the shipping costs when a customer wants it shipped via Priority Mail.

Does anyone have a fix to flag the USPS module when a product uses a package size greater than 1 cubic foot?

What variable do we need to send to USPS to flag a product that ships in a Large Package? A simple fix like that would work for me.

If someone wants to write the code for this, they could start by looking at the Canada Post shipping module. It adds several fields to the product info page in admin, so you can enter dimensions. It can then report these dimensions to the CP server correctly. So the code in that module may help you get started at least.

Rob

Hi,

Two things.

1. One of the first posts said that if a box is greater than 84 cubic inches, USPS considers it a large box. This is no longer true. Their new policy is that if a box is greater than 1 cubic foot, so greater than 12 x 12 x 12, it is a large box.

2. The way to get the shipping calculator to show the cost of the large package is to set All Packages are Machinable to False in the shipping module for USPS.

What I still need to figure out is how to switch this based on quantity. If someone orders 1 of my product, it will be shipped in a regular box. But if someone orders 2 or more, the box will be a large package.

I got hit for extra shipping costs when someone ordered 3 and they were charged the regular package cost. I sent it UPS even though they selected USPS, but it still cost me about 9.00 more than ZenCart had charged them with the shipping calculator for USPS.