[dorkbotsea-blabber] Looking for someone mechanically inclined

[Brett Wagner]

Just to frame the discussion a bit, I want to build a real version of a 
little piece of code i wrote a couple of moths ago.  Basically it's a 
nested epicycloid clock: http://islandzero.com/?q=node/3

For those not Flash enabled, imagine a clock where the origin of the 
minute hand rests on the end of the hour hand and the origin of the 
second hand rests on the end of the minute hand (At noon it would look 
like a long vertical line but at 6:15:00 it would look something like 
|_|) .  I'd like to mount the whole apparatus behind a bit of frosted 
glass and have the far end of the second hand etch the glass using, I 
assume, a chip of industrial diamond.  The other thought would be to 
size the whole thing up take it out to burningman and have it etch the 
playa.

Now if I wanted to take the easy way out I could simply put a stepper 
motor at each origin and drive the whole thing that way. However I'd 
rather take the route that is going to be both more aesthetically 
pleasing and mentally challenging and try to run the whole thing from 
one center-mounted stepper using gearing and roller chain to 
'communicate' the motion out to the outer origins.

There are a few problems that I solved in software that are puzzlers for 
me mechanically that aren't solved by traditional clock movements.  You 
will notice in the refined flash version that I linked that the minute 
and second had point the "proper" way, independent of their parents (IE 
at 5:30 the minute hand points down rather than backwards down the hour 
hand as it would if it were not artificially corrected). I'm thinking 
this might be a problem I solve in 2.0.  I also have various concerns 
about hand sag and general lack of machining knowledge thats going to 
bite me on the ass I'm sure.

I'm finding https://sdp-si.com/ to be pretty damned incredible in terms 
of what can be sourced.  I having to work past some vocabulary issues 
though. Since I have only the most cursory exposure to any kind of 
mechanical engineering ( I never set foot in shop class in high school, 
but I can set up and do basic repairs on a Hilderberg printing press to 
this day ;) ), I have to hit wikipedia pretty hard to determine what is 
meant by pitch diameter, hub diameter, face width, etc.

... so yeah, comments, suggestions, odds that I'll ever get the damn 
thing done to my liking?



Brendan Burns wrote:
> a great source is McMaster-Carr (mcmaster.com) you kind of need to
> have a rough idea of what you're looking for but they're selection is
> unparralleled.
>
> --brendan
> On 9/1/08, Wim Lewis <wiml at hhhh.org> wrote:
>   
>>  On Aug 30, 2008, at 11:07 PM, Brett Wagner wrote:
>>
>>     
>>> Of particular interest in terms of questions:
>>>   - gears, how to source them, how to talk about them.
>>>   - drive chains, where to source smaller than bicycle type chains.
>>>   - local companies that do milling of various metals and plastics
>>>
>>>       
>>  I don't know enough to contribute substantially, but I'd love for this to
>> be discussed on-list --- the -blabber list has been kind of low-traffic
>> lately, and getting my mechanical doohickeys to operate properly has always
>> been one of my weak spots.
>>
>>  Bill Beaty mentions some of them on his web page, but another source for
>> smallish mechanicals is hobby-robot and battle-bot suppliers, like Trossen
>> and Pololu.
>>
>>
>>
>> ........................................................................
>>  .........dorkbot: people doing strange things with electricity..........
>> ..........................http://dorkbot.org............................
>> ........................................................................
>>
>>     
> ........................................................................
> .........dorkbot: people doing strange things with electricity..........
> ..........................http://dorkbot.org............................
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