Hi mate just to add to and echo what some people have said above you are making things far harder for yourself with the construction method you’ve described above, your also setting yourself up for a worse finish.
By far the easiest is to build as three cabs and butt together. Then have side scribes at 38mm and a top scribe at 38mm and then a plinth (set back or flush) or skirting running along the bottom. Have two side panels scribed into the wall around the door.
Make the cabinets with backs, go for 13mm as a minimum as it’s nice and strong and will help squaring etc, 19mm is probably overkill.
If the 19mm running round is a design feature they absolutely must have then make the face frames/scribes out of 20mm material and butt those together too to achieve that look. I did this recently on a kitchen as that’s what they wanted and it looked smart. You could also make them at 38 and run a saw kerf as a shadow gap down the middle.
The reason you are making so much work is that there is potential if the wall is wonky donkey which it absolutely will be to have to scribe every shelf and upright into the wall. With a back and a face frame you walk in with them all pre built in the workshop (bring a mate for the carry) you set your ladder frames level on the floor, plonk the two cabs on top, fix the middle one In between by whatever method you like, side scribe, side scribe, top scribe, plinth/skirt scribe then side panels scribed and you are done. The back takes out any potential problems.
I hope that all makes sense mate let me know if not!
(I should add that from a personal aesthetic preference point of view which is of course an opinion It all running around in just 19mm doesn’t look very good and speaks to me of cheap mdf kind of work, if I was being forced to make it look like that I’d up the 19mm to 22 or probably 25mm to be honest I just think it would look better. I think a nicely face framed piece would look better than 25 also but it does depend a bit on the style and rest of the home, ie country house definitely face frame, modern flat as a room divider maybe in 25mm).
Thanks for the feedback and really usefull to get perspectives. I am limited to 19mm thickness veneered board from suppliers here in germany otherwise I agree that would be a bit better to use slightly thicker stock. the design that was sent me has specific shelf sizing to fit storage boxs they already have.
the same with the veneered backs I can either use that same 19mm blockboard or a 5/6mm veneered ply, nothing in the middle which leads me to believe the 19mm back is better.
even with using the 19mm thickness sides its a very tight squeeze on the right hand side to get those dimensions /shelves boxes that the customer asked for .
I see what you mean about simplifying installation having three competed boxes with and just butting the edges together, then attaching face frames.
I would feel more comfortable attaching edging in the workshop. though i guess it can be prepped so it fits well then brought to site to pin in place.
I made a quick drawing of this to get a visual. since the sides of the panels in the door way are not covered by a wall. I assume I would have to create some kind of frame that would get glued, pinned in place so it doesnt look odd having 1,9cm overhanging.
since the doors are inset it would be better having this overhang on the outside so i dont need to put additional spacers in the boxs to mount hinges and bring them flush with the edges.
I think the framed thicker outside looks quite nice definitely looks a bit more country house like you described. . with the thicker frame the dimensions of the box's would need to change.
in some ways since the 19mm lipped version is going to have lots of inset doors in each box maybe the thickness of the sides doesn't matter as much and could look more modern, which their apartment is.
definitely giving me something to think about.
