After reading all the good information in the post that Oggie started, I got thinking, what is the most optimum cabinet box construction, particularly the way the back is fastened and also the thickness of the back.

When I started out three decades ago I worked for a company that only did commercial, all the backs were 1/4 inch thick and there was a 4 inch wide x 1/2 thick plywood rail top and bottom that was staples on, then the exposed ends or bottoms had to get laminate or veneer applied.

I then worked for a shop who did residential and they used 1/2 in backs and the bottom was edgebanded and they were just stapled and screwed to the back.

Once we had all the equipment the backs were 1/2 inch material but were machined with datos and were just inserted in the cabinet and got a few beads of hot glue.

I read in the forum where some one mentioned leaving a 1/2 inch space and then use a 1/2 inch back in a dato.
My concern with that is that takes an inch out of the depth of your material, we always cut our material so we get 4 gables or top/bottoms across a 4x8 sht. Of material.

I am curious now, what is everyone doing?
Maybe my thought process is outdated as I am old?

We used to use an 1/8" back with nailers behind at the top and bottom.
When we went to a CNC router we decided to use the same material for the back as the rest of the cabinet.
3/8" dado in the back and a corresponding rabbet in the back piece.
Backs fit precisely and the cabinet is dead square.
Only one material required for the entire cabinet and less waste.

Click the link below to download the file included with this post.

Box_2.pdf

I meant to say..." 3/8 dado in the gable"

1/2" stapled. We tend to do large complicated boxes. Doing it the other ways wastes time. 95% is prefinished ply.

What Bob said. But dado and rabbet gables and bottom, overlay the top with screws. Everything lines up tight and square.

1/4 backs. 5” nailers 3/4 ply or melamine. 1/4” back dropped into dado, nailer touches wall. Dowel in the nailers. 2 materials. All cnc

1/2" backs in rabbets and stapled. I decided using 1/4" backs and stretchers was too much work compared to a single back. Plus 1/4" backs are 5mm now, so only 3/16".

1/2" back in dado 1/2 from the rear of the cabinet; edge band after dado if it is a through dado; 12-1/2" deep wall cabinets with 11-1/2" shelves still provides good yield from 49" panels

I think this depends on 2 major factors do you have a cnc and what thickness material are your boxes. When we got a cnc we saw that the yield was so much better by nesting back in with box parts that it paid for itself rather than using a thinner material. We use all 3/4" box parts so our backs are 3/4" in rabbits. They are screwed all around. So if you use 1/2" material I would go with 1/2" backs.

Uggg. Poor installers. I use 3/4" boxes with 1/2" backs and the cabinets are heavy enough.

The only thing I like about store box cabinet uppers is they are feather light because they have 1/2" sides and 1/8" backs.

Well that clears it up.

@Chris, lol my thoughts exactly

1/4 backs with 1/2 IPB nailer dado in to top bottom and sides 9/16 back .

I did as cabinet maker for a while but found that doweling the nailers was an extra step I didn't want to do so I went to industrial hot glue when in the case clamp all around the perimeter , then press in the 1/2 " nailers to the glue and run a pattern on them before pressing to back as well. Nailers are cut 1/16 less than top and bottom length so they fit in easy when in the clamp. Then we run around the joint of the case to the nailer with a senclamp gun and give it a physical fastener as well, pulls it all tight.

Tested and it makes a strong box so I am confident it will hold up on 42" uppers etc .

I like having the 9/16 to work with in case we have lumpy walks to install on , the solid backs flush with the ends can create a lot of shimming to install when you get bad walls and don't allow you to just take a planer to the sides , top , bottom etc if you need a little room for wall condition etc..

I keep the nailers out of the nest and just cut them up on the slider while the first couple of nests are being cut , then start banding parts and by the time nests are cut I'm all caught up with the banding and ready to horizontal bore with all parts on cart ready for assembly.

Have an area by the case clamp where all the nailers stack so it keeps less parts in the carts and assby tables.

Best I've come up with so far but always looking for a better way .

quick trim,

Imagine taking a piece of 1/2" ply. Shooting it down every 4" with 1/4" crown 1 1/4 staples. It would be 3 times faster than all of the glues staples 2 nailers.

1/2" full ply back is strong enough for any box. You can put screws anywhere.

I've tried most of the ways mentioned. It's really hard to beat 1/2" ply stapled. We will occansionally use 1/4" with glued on 1/4" nailers if that particular wood isn't available in 1/2" or expensive. Even then its wood glue and a few staples to hold the nailer in position

Bingo.

We use 3/4” back with a blind dado. Yes they are a bit heavier. There isn’t much of a price difference between 1/4” and the yield is so much better and it’s 1 less inventory item to manage