Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "gandolfreefer" <synchronousmosfet@...> wrote:
>
> emachineshop does also enable you to get online quotes. Of course, the prices are for idiot entrepreneurs who have millions but no brains, but it's interesting to see...
> 
> ...and, actually, emachineshop has a lot of nice built-in "real world" machining features that help you design something a machinest could actually make without too much trouble...things like menus for corner rounding, chamfering, etc., help.

Charles, I am not familiar with emachineshop, and certainly wouldn't doubt that a company of this sort (with their own software) might be over-priced. However, I wanted to mention something that could be a factor (I ask forgiveness if I am telling you something you already know):

CAD software makes it really easy to specify things using as many digits of precision as you want to use. As a result, many engineers (and amateurs) are tempted to give, say, 4 digits of precision (down to .0001" or even finer. The problem with that, when it comes to machining, is that you pay -- a LOT -- for extra precision. Most machine shops can machine something within +/-.001" without much trouble, but specifying it to within +/-.005" makes it a piece of cake, and therefore a good bit cheaper. On the other hand, machining to within +/-.0001" requires a lot of extra care -- and actually is starting to be meaningless unless you specify the temperature at which this must be measured. So a simple part might cost you $1 per part to have made to +/-.005", but it would go up to $5 per part for +/-.001", and up to $500 per part for +/-.0001".

Again, I apologize if I am telling you something you already know!