RE: [CAD_CAM_EDM_DRO] Re: degrees of freedom Was: Angle Iron Ways

Dennis,

"kinematic" support as an engineering term simply means nonoverconstrained
support.

I'll give an example: A three legged stool on a floor is kinematically
supported. A four legged stool is overconstrained.

With scraping and other means of generating plane surfaces it is possible
that a reference instrument (like a surface plate or level) will only
contact
a test surface at one or two points. If that happens it will rock and give
inconsistent readings. If it contacts in three places only (kinematic
support)
this is prevented.

So it is typical to rough in a surface to be rendered flat so it contacts
the instument in three spots. As the flattening process proceeds these three
spots grow until they merge into a plane surface.

There is much more on kinematic design principles in engineering text such
as
Slocum's "Precision Machine Design".

Les

Leslie M.Watts
L M Watts Furniture
Tiger Georgia
(706) 212-0242

Main page:
http://www.lmwatts.com
Engineering:
http://www.lmwatts.com/shop.html
Cnc surplus for sale:
http://www.lmwatts.com/forsale.html
Carved signs:
http://www.lmwatts.com/signwp.html

-----Original Message-----
From: CAD_CAM_EDM_DRO@yahoogroups.com
[mailto:CAD_CAM_EDM_DRO@yahoogroups.com]On Behalf Of Dennis Schmitz
Sent: Saturday, August 19, 2006 12:37 AM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] Re: degrees of freedom Was: Angle Iron Ways


And there goes another two hours of time I could have been using
productively...

On 8/18/06, Dennis Schmitz <denschmitz@...> wrote:
> I was reading the description of hand tooling a precision flat and was
> trying to figure out what he meant by "kinematic" since it could be
> lots of different things, and one of my google searches lead here:
>