3D Printed Washer Sorting Trays: Trays for Every Washer Size

Introduction

Washers are the most-mixed fastener in any workshop. They are flat, they stack, they slide into each other’s piles, and sizes differ by millimeters that your eye cannot reliably judge. A jar of washers looks organized until you need a specific one — then it is a flat metal haystack, and the washer you need is always at the bottom.

The problem is that washers sort by three dimensions at once: outside diameter, inside diameter, and thickness. Two washers can share an outside diameter and still fit different bolts, and a fender washer looks nothing like a spring washer of the same nominal size. A single mixed container makes all of that invisible.

3D printed washer sorting trays fix that with compartments shaped to the washer: round wells for flat washers, deeper wells for spring washers, wide wells for fender washers, each labeled with its size. Sort once, and every washer you reach for is the size you meant to grab — no more stacking, measuring, and restacking by hand.

This guide covers designing, printing, and using washer sorting trays for home workshops. These are storage aids for small hardware — nothing structural, nothing load-bearing — and they complete a sorted fastener wall.

What You Need

A washer tray is a shallow tray with wells, easy to print on almost any home machine. The design work is auditing your washers and choosing well shapes that suit them.

Materials and tools

• A home 3D printer with a build area of roughly 150 mm in at least one direction
• PLA filament for indoor trays, or PETG for garage and workshop use
• Your washer collection, sorted loosely by size and type before you design
• A tape measure or calipers, a pencil, and a small ruler
• Sandpaper or a small file for cleanup, plus labels or a paint pen
• A small magnet or scoop for moving washers between containers

PLA is perfectly fine for a benchtop tray: it is rigid, prints cleanly, and holds its shape indoors. PETG is the better choice for a garage, where heat and humidity are harder on PLA. Print trays with enough walls that well dividers do not flex when you press washers into them.

Suggested print settings

• Layer height: 0.20 mm balances speed and accuracy; 0.16 mm if well edges look rough.
• Walls: At least 3 perimeters — dividers need to stay upright under handling.
• Infill: 20 to 30 percent, grid or gyroid, is plenty for a tray that carries only washers.
• Top and bottom layers: 4 or more, so the tray base stays flat and rigid.
• Orientation: Print flat, base down, for the flattest tray bottom.
• Supports: A good open-tray design needs none.

Print one test tray first and try it with your real washers before printing a full set.

Design Considerations

A washer tray is only as good as its wells. Shape them to the washer, not to a generic grid.

1. Audit your washers first

Gather every washer you own and sort them into piles by type — flat, spring, fender, and lock — and then by size within each type. Count how many piles you actually use; most home workshops need eight to twelve wells, not thirty. Designing for the washers you own beats designing for a catalog. Keep one well for odd strays, and keep metric and imperial strictly separate, even when sizes look close.

2. Well shape and size

Round wells suit flat washers: size each well to its washer’s outside diameter plus about 5 mm of finger room, so you can pinch a washer out of a stack. Spring washers need deeper wells, since they do not stack flat, and fender washers need wider, shallower wells. Depth of 15 to 25 mm suits most washers; deeper wells hide small washers at the bottom. A small finger notch in each well’s rim makes lifting the last washer out much easier.

3. Stacking versus laying flat

Washers can stack in a well or lie flat in a compartment, and each suits different sizes. Small washers stack well in round wells, staying visible as a neat ring. Large fender washers lie better flat in a square compartment, where you can see the whole washer at a glance. Mix well shapes in one tray to suit your collection rather than forcing every washer into the same shape.

4. Labels and modularity

Label every well with its size and type, using a printed label slot, an embossed size on the divider, or a paint-pen mark. A label slot that accepts a small paper card is the most flexible, since your size mix will change. Design trays to stack or sit side by side in a standard footprint, so adding a second tray later does not mean reorganizing the first.

Step-by-Step: Printing and Assembly

1. Audit and sort your washers into piles by type and size, and count your piles.
2. Measure the largest washer in each pile — outside diameter, inside diameter, and thickness.
3. Model the tray, with one well per pile plus an odd well, in your chosen footprint.
4. Print a test tray and try it with your real washers.
5. Check the fit. Washers should stack or lie neatly, lift out easily, and stay in their own well when you tilt the tray gently.
6. Clean it up. Sand rough edges and clear any stringing from well corners.
7. Adjust if needed. A well that is too tight or too deep is a quick model tweak; reprint rather than living with it.
8. Print the final set, add labels, and fill each well with its size.

Sorting once, properly, is what makes the tray system pay off every time after.

Step-by-Step: Using Your Washer Sorting Trays

1. Fill one well at a time, checking each washer against the label before it goes in.
2. Place trays where you work. On the bench for active projects, on a shelf for storage — not both, or washers migrate.
3. Return washers immediately after a job. The habit that keeps trays sorted is putting leftovers back the same day, not “later.”
4. Use the magnet or scoop for moving washers, so you do not scatter a well across the bench.
5. Top up from bulk storage when a well runs low, rather than buying a new mixed box each time.
6. Check labels monthly. If a well keeps collecting the wrong size, its label or position is confusing — fix the label, not the user.
7. Add a tray when you outgrow one, keeping the same footprint so trays stack or sit together neatly.

The tray works when returning a washer becomes easier than dropping it in a jar. Design for that habit.

Tips for Better Results

• Sort by inside diameter first. The hole is what must fit the bolt; outside diameter matters once the hole matches.
• Keep a size gauge in the tray. A small printed strip with rings for each size settles arguments about which pile a washer belongs to.
• Use one color per washer family. Flat washers in one color tray, spring washers in another, and the bench stays scannable.
• Add a finger notch to every well. Lifting the last washer out of a smooth well is frustrating without one.
• Pair trays by family. Once washers are sorted, the same system works for other hardware — our guide “3D Printed Bolt and Nut Sorting Bins: Bins That Sort Hardware” applies the same sort-once logic to bolts and nuts.

Common Mistakes to Avoid

• Designing wells before auditing. Guessing your sizes means wells that fit nothing you own.
• Making wells too deep. Deep wells hide small washers and tempt you to tip the tray out.
• Mixing metric and imperial. Sizes that look close are not interchangeable; keep them strictly separate.
• Skipping labels. An unlabeled tray becomes a mixed jar with walls within a month.
• Overfilling wells. A heaped well spills into its neighbors the first time you move the tray.
• Forgetting the odd well. Strays need a home, or they end up in the wrong well.

Care, Storage, and When to Choose an Alternative

Brush out dust and metal filings, wipe trays occasionally, and reprint any tray with cracked dividers or a warped base. PLA trays in a hot garage can warp in summer; switch those to PETG. Store trays stacked or side by side on a shelf, lids on if they travel.

Sometimes a different system fits better. If you carry fasteners to job sites daily, a manufactured compartmented case with latches beats an open tray. If you stock hundreds of each size, small parts cabinets with drawers scale better than trays. For the home workshop — a bench, a shelf, and a collection that fits in a few trays — printed trays are cheaper, better fitted, and easier to extend. The same tray logic works for other small hardware too, as in “3D Printed Nail and Brad Organizer: Sort Nails by Size“, which sorts nails rather than washers by the same compartment principle.

FAQ

How many wells do I really need?

Most home workshops need eight to twelve: three or four flat washer sizes, two or three spring sizes, two fender sizes, and one odd well. Audit your actual collection first — designing for sizes you do not own wastes tray space.

Is PLA strong enough, or do I need PETG?

For an indoor benchtop tray, PLA is plenty strong with reasonable walls. PETG is the better keeper for garages because it handles heat and humidity better. Divider thickness matters more than the filament brand.

My washers keep ending up in the wrong well. What is wrong?

Usually the labels are unclear or two wells hold very similar sizes. Make labels bigger, add a size gauge to the tray, and consider merging near-identical sizes into one well if you genuinely cannot tell them apart in use.

Can I scale the trays for a larger washer collection?

Yes. Design trays in a standard footprint and print more of them rather than one giant tray. A giant tray gets heavy, hard to carry, and awkward on a bench; several standard trays stack and rearrange.

Conclusion

A jar of mixed washers costs you time on every job: time hunting, time measuring, time restacking a pile to find one washer. A printed sorting tray costs you one sorting session and a few hours of printing, and then pays you back every time you reach for a washer and get the right one first try.

Audit your collection, print a test tray, and sort once, properly. The next job starts with a wrench in your hand, not a jar tipped out on the bench.

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