# A mudroom

Our remodeled home included a mudroom and I was tasked to build the fancy hall trees that would store all our kids shoes, jackets and stuff. I am a member of the Wood Whisperer Guild and like studied their design.

# Design

Designing and building things parametrically in AutoDesk Fusion 360 has been a game changer for me, but this one was tricky since I wanted the start and end of the hall tree to include the width of the ply. The first and last cubby width would be width would be called a and the middle widths would be b. This is where a little math made the design a lot more clear.

$$a = \frac{1}{4} (l - 6\, w) \; \text{and} \; b = \frac{1}{4} (l - 4 \,w) \; \text{and} \; k = \frac{l}{4} - \frac{3}{2}\,p$$

Or more generally:

$$b = \frac{l}{n} - w \; \text{and} \; a = \frac{l}{n} - \frac{3\,w}{2}$$

where n is the number of bins. We explored 4, 5, 6 to figure out what best used the space.

First, I needed to design five cubbies with equal width. I love building things, but use stock pieces and don't have the time to glue up countertops or make faceframes. Because of this, I built this on top of an Ikea Karlby countertop (Article no: 703.352.12) which is super straight, low cost and beautiful. I played with the design to optimze the cutouts from 4x8 sheet of three quarter inch plywood. As an aside, I get my grade A or B plywood from Huston Lumber. The Home Depot stuff has a thin veneer and risks delaminating and is a lower version of grade C.

The final design resulted from lots of discussions in the space.

And used the following parameters. Calculating parameters made the design a lot easier to build.

Parameter Unit Value
room_length m 3.068 m
room_height m 2.5 m - 9 cm
ply mm 19 mm
countertop_height mm 37 mm
countertop_depth mm 650 mm
cabinet_width mm 575 mm
cubbies_length mm room_length - cabinet_width
cubby_depth mm 400 mm
base_cubby_depth mm 0.9 * countertop_depth
facing_width mm 1.5 in
facing_ply mm ply
a mm ( cubbies_length / n ) - ( 3 * facing_width ) / 2
b mm cubbies_length / n - facing_width
k mm ( 1 / n ) * ( cubbies_length - n * ply )
base_cubby_height m 18 in - countertop_height
top_cubby_height mm room_height - countertop_height - base_cubby_height
shelf_width mm k + dado * 2
cubby_height mm 1300 mm
len mm cubbies_length / n
n 5

I used the parametric features pretty extensively, basing everything off of fractions of the the total shelf length and room height.

The heart of fusion 360 is the sketch. By fixing the sketch and understanding the timeline, its possible to break down the design into a set of modular components that help you keep complex designs under control.

From there, I was able to use mapboards pro to get a cutlist, which I uploaded to cutlist optimizer to produce a fairly optimized design that efficently used three sheets.

Overall, fusion 360 estimates the total weight as 172 Kg, which is probably accurate with the long walnut countertop. I was planning on doing a stress analysis on the design, but I'm saving that for a future project.

# Manufacture

After understanding my design, I primed everything with BIN primer that sprays on easily using my HVLP Harbor Freight gun. I use Harbor Freight guns for BIN because the cleanup is easy and I can frequently replace the gun. Since I sand the primer, the finish matters a lot less. For finish work, I use my FujiSpray MiniMite.

After priming, I used my Festool TS55 track saw to cut down the sheets. To make everything accurate, I made two jigs using 1/4 inch thick plywood and Starbond CA Glue. Reading up on ETHYL CYANOACRYLATE is recommended. It's pretty cool.

This let me back super accurate cuts without needing to move big sheets of plywood on the table saw.

After the pieces were cut, I went back to the model to update the dimensions I actually cut, which at my current skill level is around $$1 \pm \text{mm}$$. In order to get everything consistent, I use the table saw to cut things down to equal dimensions and ensure everything is square.

Dimension Value (mm) My Value
Shelf Width (a) 482.1 481
Shelf Width (b) 491.6 492
Top Depth 400 399
Base Depth 585 582.5
Vertical Side Height 1952.8 1953
Base Height 420.2 419
Ply 19 18.67

## Pocket Holes

I had to figure out how deep to cut the pocket hole with the 6mm dado. After building a drawing, it made sense to set the depth of the jig to $$\frac{5}{8}$$ per: