Small Parts Organization

There are all sorts of reasons to amass a large number of various small items depending on your hobbies and interests. Whether it’s hardware, electrical components, plastic bricks, or any other passion, things tend to pile up. There are a number of ways to deal with this - drawers, tool cabinets, and so on - but my favorite is modular boxes. These boxes have spaces for items of various sizes and can be carried around to where you need them, while still being stored in a central location for quick reference.

Organizer Systems

There are a large number of organizers made by various companies, and a quick search of the Internet will find people building systems with each of them. Having tried a few, here are my thoughts:


The canonical example of modular organization is Adam Savage’s Sortimo Boxes. Sortimo T-BOXX is an ultra-premium European offering - functionally one of the best choices (durable, keeps parts well separated, pull-out bins, spare parts easily available), but the price is very high. For a long time they were very difficult to obtain in the United States. There is now a US Store but the boxes start at $64 apiece at the time of writing, which is more than I’m willing to pay.

Harbor Freight

At the opposite end of the spectrum we have the Harbor Freight Parts Case. It’s a very popular option due to its low price and its wide availability in the United States. That said, having used some of them my experience is that there’s a significant amount of flex in the lid which means that parts can bounce around the containers when carried or shaken:

Harbor Freight Parts Organizer with parts moving between bins

The size of the default containers is merely OK - many are smaller than I’d like - and there appears to be no way to purchase spare or alternative sizes, so this system doesn’t give you the flexibility offered by many others. If money is tight, it’s an option, but it wouldn’t be my first choice.


Stanley makes a number of modular organizers. I haven’t used them, but reviews indicate that their durability and is high and their amount of flex is low. Their prices are double that of Harbor Freight, but the increase in quality is worth it. The biggest limitation is once again that you can’t buy individual organizers of sizes to optimize your system - you have to buy new boxes to get any more organizers.


Allit is a brand of German modular storage cases sold by Lee Valley tools. They offer 3 styles - Economy, Small Professional, and Large Professional - but the price jump for the professional models is very significant, so I’m going to focus on the economy boxes. The economy box is priced competitively with the Stanley options - $21.50 US at the time of posting - but it offers the ability to purchase individual organizers to optimize your boxes to whatever layout works best for you.

Allit organizer

I’ve been very impressed with Allit. The build quality is top notch - there’s no detectable flex in the lid. I can hold a box full of screws upside down and shake it aggressively and I’ve never had a part move between bins. The organizers come in and out easily but do not shift while being carried. The lid stays attacked firmly. I haven’t had any issues with any of my boxes while using them. The boxes are arranged in a 4x6 grid of 2x2" squares, and organizers are available in 1x1, 2x1, 2x2, and 2x3 sizes. You can purchase whatever combination you want and create your optimal organizational scheme. This flexibility is what led me to choose Allit for my organization.


The simplest way to deal with multiple organizers is simply to stack them. All of these systems will stack on top of each other securely, but if you want to access any box other than the top you have to move things around. The obvious solution is to build a shelf to give access to the various organizers. These organizers can be as large and elaborate as you have space for, but if you’re trying to keep things simple and compact (to fit into a tight space, for instance), the most space-efficient (and easiest) way is dado hangers.

Diagram of organizers hanging in a storage unit

The basic pattern is simple - a groove slightly wider than the hanging section of the organizer spaced slightly wider than the overall height of the organizer. The important dimensions to take note of are the following. If you’re using another system, you can update these numbers to work with your organiuzers:

Dimension Length
Height (Including Feet) 2 3/16"
Height (Including Feet, without side hangers) 1 5/8"
Width 14 3/8"
Width (Without side hangers) 13 13/16"
Depth 11 1/2"
Side Hanger Width 9/32"
Side Hanger Height 14mm (0.55in)

Interior Dimensions

The Allit boxes are interesting because the side hangers are not very wide - wide enough to support the width of a loaded box, but almost no slack side to side. Thus, our desired internal width will be 13 7/8" - an extra 1/16" to avoid rubbing on the edges, but no more unless we risk having the box be significantly off center and slipping off an edge. If your system had significantly wider hangers (at least an inch), you could increase this to 1/8" or so to give an additional margin, but in practice I’ve found 1/16" to work fine.

The interior height will depend on how many shelves you want and the available height for your shelves. To fit 9 shelves in my desired location, I only had a spare quarter inch, so I added 1/8" of padding to the top and bottom.


The grooves should be slightly taller than the hangers, but not significantly. For Allit, the shelves were slightly less than 9/16" tall. I did a test cut with 9/16" dadoes and found that the drawers slid in and out with no issue, so I saw no reason to go any wider. The depth of the dadoes should be slightly more than the width of the hanger - going even deeper isn’t a problem for the shelf, so long as you don’t comprimise the strength of the frame. I aimed for a depth of 5/16" which was more than enough, though the cut ended up being a bit deeper. You could probably get away with 5/16" in 1/2" plywood material, but I made the frame out of 3/4" plywood for extra strength, so I had no concerns about strength and the depth of the cut.

The spacing is determined by the height of your organizer and its handle. At a minimum, you need to be slightly wider than the height of the organizer. For Allit (2 3/16" height) I recommend a spacing of 2 3/8". The extra 3/16" gives plenty of flexibility for any shifting while inserting or removing organizers. However, be sure that your spacing leaves enough room to easily grab the handles. The handle on the Allit boxes is easy to grab even with the boxes stacked directly on each other, so there’s no issue there, but not all systems may be so versatile.

Sizing the shelf to fit

Once you know the desired height of your shelf, you can figure out how many organizers will fit by taking the height (minus twice the material width for the top and bottom) and dividing it by your spacing. Round down to find the number of shelves, and look at the remainder to determine how much extra slack you can add to the top and bottom. In my case I was fitting into a space 23" tall, so I could make (23 - 2 * .75) / (2.375) = 9 shelves with 3/8" of extra clearance split between the top and bottom.

With this in mind, you can determine the positioning of your cuts. The first cut is computed as follows:

Width of bottom material + Bottom Padding + Distance to the bottom of the first dado

Thus, running the bottom of a side piece along the fence, the cut will be positioned correctly. For Allit and 3/4" material, this means 3/4" + 1 5/8" + the bottom spacing. While even spacing would have been 3/16", I left only 1/8" of spacing to make the math work better - this put the first dado at 2.5". From there, the rest were at increments of 2 3/8": 4 7/8", 7 1/4", and so on.

If cutting the dadoes on a table saw, remember to account for the increased blade width when positioning your fence. Since my normal blade is 1/8" thick and the dado stack was 9/16" wide, this meant adding 7/16" to every measurement when setting my fence.


When assembling the unit, it is critical that everything is assembled square. The tolerances in this design are very small, and being off by a few sixteenths of an inch could mean your organizers not fitting in or falling out. The first step is to attach the top and bottom to the sides. Any fastener should work - I built my initial prototype with brad nails and it worked great with any amount of weight I threw at it. For my final product I used a few brad nails to hold it square and then added screws.

Once the top and bottom are installed, you will want to install a back piece. This serves two purposes: Preventing the organizer from sliding back too far and holding the sides square. I found that my plywood was slightly bowed - the middle was 3/16" wider than the top and bottom, which meant that boxes in those positions were barely holding in. The easiest way to fix this is to use clamps to bring the width in while installing back pieces:

Clamping the organizer to adjust the width of the middle

Don’t tighten the clamps all the way - you can cause an inward bow. Check the width of the organizer at various points while adjusting the pressure to ensure a consistent width throughout the organizer. Once it is held in place, you can install the back piece - I made mine in two halves to make it easier to install one half with the clamps out of the way.

Once the back piece is installed, double check the width throughout. It may not be perfect in the front - mine still increases by about 1/16" in the middle - but by being held together in the back your clearances should be good enough to hold everything securely. Sand and finish as desired, and your final result will look something like this:

The finished organizer

Again, this design can be scaled to any degree you want - you could build a rolling cabinet with dozens of these, a smaller unit with 3 or 4, or whatever fits your system. The goal here is maximum customizability.