Re: [Phys-l] Sig figs

[Joseph Bellina <inquirybellina@comcast.net>]

My experience in a aerospace research lab was somewhat different.  I  
had a machinist assigned to me who I chatted with on a daily basis.   
He wanted to know what was important and what was not because  
precision took time and money.  If a rough cut would work, he would  
do that, if I needed to a "thou" or better he would do that.

joe

Joseph J. Bellina, Jr. Ph.D.
Emeritus Professor of Physics
Co-Director
Northern Indiana Science, Mathematics, and Engineering Collaborative
574-276-8294
inquirybellina@comcast.net




On Oct 17, 2010, at 4:38 AM, Michael Edmiston wrote:

> I mentioned in an earlier post that it is helpful to let the  
> machinists know
> what you are up to.  If they are told that one piece fits inside  
> another
> piece, and you would like 0.002" clearance between the two, then  
> they will
> make it that way.  If you just give the dimensions, and they are  
> doing +/-
> 0.001 work, you could end up with no clearance.  Of course you can/ 
> should
> specify the outer piece as "minus none" and "plus something" and  
> vice-versa
> on the inner piece.  But I always found that machinists liked talk  
> to you
> about you are doing.  They might not understand the physics, but they
> understand the mechanical parts, and they can often make design  
> suggestions
> you haven't thought of.  So I would visit the shop with sketches and
> half-finished drawings, and ask for advice.  Of course this only  
> works in an
> environment where you can talk to the machinists face-to-face as  
> opposed to
> simply submitting finished drawings.