The easiest way is to get a french fry cutter and figure it out.

The french fry cutter we support is available at

http://www.storeshop.com/french_fry_cutter.html

This will make a good basis for your thinking, as it's a quality product, while being affordable and attractive.

The french fry cutter has an ingenious lever system to exert force on the potatoes while minimising effort.

The body is of the french fry cutter is constructed from ABS Acrylonitrile-Butadiene-Styrene as used in automotive parts and pipes, chosen for toughness and stability, and to resist chemicals, such as potato juice :)

The french fry cutter blade is stainless steel for rust resistance and to last longer.

If you look at the french fry cutter blade grid, you will notice the type of call an industrial designer has to make. Some folk like thin french fries, some thick meaty chips. The designer has made the french fry cutter produce fries somewhere between the sizes so that everyone will be happy.

Also notice how the industrial designer has got into the mind of the consumer when creating the french fry cutter. See the ease of cleaning features and the suction base so that the french fry cutter does not slip in usage.

The look of a unit helps sell the unit. This has not been ignored in the french fry cutter design. Notice the red highlights on the handle, slider and french fry cutter blade surround. This is attractive adding a splash of color to a kitchen without being "too much"

The french fry cutter is apart of a range, see http://www.storeshop.com so further consideration would have been made how the french fry cutter fitted into the range in terms of market, looks, price point and quality.

As discussed if you would like one the french fry cutter is available from

http://www.storeshop.com/french_fry_cutter.html

Hope that this is helpful to you