My Five Principles for Great Physical Product Design

  • Economical to produce
  • Easy to maintain & repair
  • Foster long term working relationships with your suppliers
  • Appreciated for their aesthetics
  • Handed down to future generations
  • Reliably achieve their intended function for years to come
  • Emphasise your design decisions to the customer, without further explanation

Principle 1: The design respects the end manufacturing process.

A precision centre finder from Rutlands, using CNC’d Anodised Aluminium
  1. The time it takes to machine the part, similarly, the number of operations it requires. How many features does your part have — can you simplify it?
  2. Can the part be machined from one side only? If so it will be cheaper, if not they’ll have to flip it to machine the underside which takes a bit of time, or means they’ll need to use a better machine that can flip automatically, which also increases the price.
  3. What’s the smallest bit size the machinist will need to use? If it’s a small bit, then they will need to charge you for every bit they break, which happens a lot. This slows down production too if the smallest bit is something like a 2mm diameter you should be ok. You can tell your smallest bit size by the smallest inside radius your part has.
  4. The raw cost of the material. The most common machining metals and approximate costs are Aluminium 6061 ($4 per kg), Stainless steel ($5/kg), Brass ($6.9/kg), Copper ($8.4/kg) and Titanium ($ 16.9/kg). Prices as of 13/01/21 courtesy Yi Xin, Dongguan.
  5. The finishing processes required, sandblasting, anodising, blackening etc all add processes and cost.
A custom Titanium, Sand Blasted Swiss Army Knife made using CNC.
A simple yet beautiful cast-iron casserole dish. It has a natural finish with imperfections caused by the sand casting process.

Principle 2: Eliminate Unnecessary Details

Feit Desert Boots, made with a single formed piece of suede, stitched onto its sole and heel.
Another example of simple, honest construction techniques.

“…But Esslinger dictated, and Jobs enthusiastically agreed, that there would be no such “draft angles” that would ruin the purity and perfection of the cube.”

Principle 3: The design works perfectly, even in our imperfect world.

iThe apple watch strap, simple but effective.
If your design still works through the extremes of inaccurate manufacturing techniques, then you’ve cracked it.

Principle 4: The product ages gracefully.

A vintage brass bodied Leica camera with its years of use showing through, still looking brilliant.
Two of my separate great grandfather's tools, both nearly 100 years old, still in good shape.

Principle 5: The construction is honest and transparent.

The engine on the left had been made using transparent construction techniques, whereas the BMW engine on the right has a plastic cover and “go faster holes” designed to make it look more ‘aggressive and manly’.
Every rivet, dial and engraving have a purpose, which for me, makes this mesmerising.





Alex is a product designer and entrepreneur. He is director of Parallel Products that makes well considered, personalised products.

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Alex Peet

Alex Peet

Alex is a product designer and entrepreneur. He is director of Parallel Products that makes well considered, personalised products.

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