Thursday, July 18, 2019


Sometimes machinists make strange objects for one reason only:  to flex.  I have to say “to flex” is not a word from my vocabulary but it is commonly used amongst our young watchmakers.  And here is an example of what a flex is:  a piece of steel machined to look like a miniature staircase. 

The difference between the lowest step and the top one is 1mm. The step between the stairs is one-fifth of a millimetre or 200 microns. Apart from the perfect cut, machining a staircase like this is not really that difficult in any professional machine shop.
The second piece is a bit more challenging.  Its highest step is half of the height of the lowest step in the previous piece which is 100 microns.  These staircases are barely visible and we call them the ant steps, where each one is 20 microns apart.  Again, there are a number of workshops in Australia capable of making ant staircases.

The third staircase is really the flex piece.  Again, the highest step is half of the ant step, going from 10 microns down to zero in intervals of 2 microns, and the last three steps are exactly 1 micron apart.  The staircase is not visible to the naked eye but it is only under microscope.  And this is really where we are reaching what is mechanically possible to machine on a 5 axis mill.
Here is a mind blowing fact: a 700kg Z axis which holds the spindle is moved 1 micron vertically at a time, to make a cut.  The total cutting error - which includes the wear of the tool, the play in the ceramic ball bearings, the ball screw end shake, and the parallelism of the hydrostatic guide – all combined is under 0.3 microns.
The full credit for this flex goes to Josh, who spent less than one afternoon flexing.
We would be really keen to hear from any other business in the field of precision manufacturing who can match “the staircase challenge”.  Slice a micron in half and we will say "Respect".

Of course, all three pieces are in our city office available for inspection but, most importantly, Manufactured in Australia.

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