FurnitureShelvingEasy

Bolt-Together Shelving Unit

A 900 x 300 x 1830 mm five-shelf unit built from four uprights, bolted cleats and loose birch plywood shelves: no glue, no screws into end grain, fully demountable.

Designthe dimensions everything else is derived from

Finished size

900 wide x 300 deep x 1830 mm high

Uprights

4 off 50 x 50 mm, 1800 mm long

Shelves

5 off 800 x 300 x 18 mm birch plywood

Cleats

10 off 300 x 40 x 40 mm, bolted to the uprights

Back braces

2 off 900 x 50 x 25 mm, bolted

Shelf spacing

340 mm centres

Cut list sizes are finished sizes. Add 5 mm to the width and 25 mm to the length of every solid-wood part for saw kerf and planing, and buy boards oversize by one thickness so a bowed board can be flattened rather than relegated.

Materialswhat each part is made from, and why

All materials

Birch Plywood · 5 shelves, 800 x 300 x 18 mm

A 800 mm span in a 18 mm plywood shelf is stiff because the plies cross; the same span in solid timber at that thickness would sag visibly under books.

Fir (Douglas) · 4 uprights, 10 cleats, 2 braces

Used in compression and as small blocks, which is the one job softwood does as well as hardwood. Every piece is bolted through, so there is no thread to strip.

Cut listfinished sizes, worked back from the design

Part	Qty	Finished size	Stock
Upright	4	50 x 50 x 1800 mm	Fir (Douglas)
Shelf	5	800 x 300 x 18 mm	Birch Plywood
Cleat	10	300 x 40 x 40 mm	Fir (Douglas)
Back brace	2	900 x 50 x 25 mm	Fir (Douglas)

Fastenersquantities and lengths that follow from the joints

All standards

Item	Qty	Grip	Standard
M8 x 110 hex bolt	20	90 mm	ISO 4017
M8 x 100 hex bolt	4	75 mm	ISO 4017
M8 plain washer	48	—	DIN 125 A
M8 nylon-insert nut	24	—	DIN 985

Grip is the sum of the clamped thicknesses. A bolt has to clear the nut by two full threads, which is what sets the length that appears in each row — not a preference.

M8 x 110 hex bolt · grip 90 mm

Two per cleat end, ten cleats with two ends each. Grip is the upright (50) plus the cleat (40); add the nut and two washers and 110 mm is the next stock length. ISO 4017 →

M8 x 100 hex bolt · grip 75 mm

Two per back brace, one at each end. Brace (25) plus upright (50). These are what stop the unit folding sideways, so they are not optional on a tall unit. ISO 4017 →

M8 plain washer

One under every head and every nut, twenty-four bolts. Softwood cleats crush and the joint goes loose without them. DIN 125 A →

M8 nylon-insert nut

A shelf unit is loaded and unloaded constantly and the insert keeps the bolts from backing out. DIN 985 →

Toolsand what each one is for on this job

All tools

Drill

Boring 8.5 mm clearance through cleats and uprights.

Twist Drill Bits

8.5 mm for M8 clearance, plus a 20 mm bit for the counterbores in the outer face of the uprights.

Circular Saw

Cutting the 18 mm plywood shelves, which are too wide for a bench saw without a support.

Socket Set

Twenty-four nuts.

Combination Wrench

Holding the head in the counterbore.

Tape Measure

Setting the five cleat heights off one end, so the shelves end up parallel rather than each one level with the last.

Order of workthe sequence, and where it is not free to change

Cut four uprights to 1800 mm. Cut all ten cleats at once to the same length; they set the depth.
Mark the five shelf heights on one upright and transfer the marks to the other three with a story stick rather than a tape.
Clamp a pair of uprights to a cleat and bore all three at once. Repeat at the same height on the second pair.
Bolt the ten cleats on, snug not tight.
Bolt the two back braces diagonally on the rear uprights.
Drop the five shelves in loose, then tighten everything once the unit is standing square.

Where it goes wrongthe three failures worth designing out

Leaving out the back braces. Ten bolted cleats make a unit that is stiff in one plane only; without bracing, a 1830 mm unit leans and the bolts start working.
Marking each shelf height independently with a tape. Five small errors become five visibly uneven shelves; one story stick transferred to all four uprights makes them identical.
Fastening the shelves to the cleats. Loose shelves can be lifted out and cleaned, and they do not fight the frame when the plywood picks up moisture.

Frequently asked questions

Why 300 mm cleats on a 300 mm deep shelf?

So the cleat and the shelf end flush front and back. The cleat then runs past both uprights it is bolted to, and the bolts sit either side of the upright rather than relying on a single short cleat per side.

How much will each shelf hold?

That depends on the shelf, not the bolts, and it is the one figure this project deliberately does not quote. Plywood deflection depends on grade, span direction and how the load is spread; a number invented here would be a number to rely on wrongly. The defensive answer is a support at mid-span.

Can it be built taller?

Only with bracing that grows with it. The load on a back brace goes up with the square of the height, so a unit at 2400 mm wants two braces per rear upright rather than one.