[time-nuts] New +/- 1 sec in 100 days mech clock

Jim Lux jimlux at earthlink.net
Mon Apr 20 20:10:45 EDT 2015


On 4/20/15 12:59 AM, Attila Kinali wrote:
> Moin,
>
> On Mon, 20 Apr 2015 00:40:06 -0700
> "Tom Van Baak" <tvb at LeapSecond.com> wrote:
>
>> Mechanical, yes. Home brew, no. It is an absolutely stunning clock,
>> both in beauty and performance.
>
> Given the fact that a CNC milling machine can be bought quite cheaply
> today, i would say that homebrew is easily possible. All you need
> is a good understanding on different materials and how to machine them.
> (This can be aquired using various machining books out there)


I don't know about that..  I suspect that more than a CNC mill is 
required: there's often a lot of craft and art in precision machinery 
(like optical systems).  There's a lot of craft in high performance 
quartz oscillators: selecting the crystal, mounting it in a holder so 
that it doesn't see untoward stresses, doing the seals, etc.


Certainly, a CNC makes a lot of the fabrication easier, and the fact 
that you can mail order CNC parts is even cooler. Front Panel Express, 
for instance, is a great way to make breadboard plates for connectorized 
modular RF components. It's what I use after I decide that double stick 
foam tape isn't appropriate any more.

But for things like threads and helices, your standard CNC isn't going 
to do it.
And I suspect the machining of the gears might have been done in a 
special way (other than a dividing table).  For these kinds of high 
precision applications, there's a lot of tricks in getting all the 
periodic errors to cancel out:essentially to make the system precision 
higher than some of the manufacturing steps.

Look at the ruling engines used to make diffraction gratings for instance.





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