One avenue to consider is volunteer work. There are many organizations that can
use/benefit from free software development that would be glad to provide a reference in
return for that work.

Its a win-win, has a feel-good benefit and was very helpful to me when I did this jump.

There are many famous children's authors that started out by telling stories
to one child, and then went on to write them down for all children. Telling
stories to one child will not make you rich, nor is it a necessary step on
the way to riches, though if the one child hates the stories perhaps a
different path should be considered. It is similar with software. Writing
software for one client and then extending it to many is a well-trod path to
success. The first app cost N & lotsa zeros, the second copy costs cents.

I assume that your custom machines tend to go into certain groups of
industries. In your place I would look for a small application that would go
into those industries and write that. Owning one of your machines might well
introduce new problems into those industries, for example ordering materials
for those machines, spare parts maintenance, perhaps a manual based on a
database. If you can offer a free or cheap solution to your customers and to
your potential customers the program itself can act as a referral, you get
to design the Splash screen and insert your name into the suppliers table.
If pursuing this strategy be aware that a Web site might be a more
profitable way of achieving the same goals.

As an example, I used a program I had written for calculating near minimum
paths (travelling salesman problem) for printed circuit board drilling
machines to get sales for PCB drilling machines, and wrote a program that
translated drilling programs between types of machines which also got many
sales. These applications were not free but under-priced, and generated
considerable income in their own right.

Yahoo's  David_F_Cox

Jeff -
 Access is a "dime a dozen" program.  Everyone knows how to write
queries and forms to get them to a point.  Trying to make a business
out of Access coding is like trying to make a business out of painting
only it's a bit more difficult; not only can everyone do it but there's
less mess to clean up at the end of the day.

 Start with sites like guru.com, elance.com, rentacoder.com and the
like.  And if you're not frustrated enough to give up that line of work
after constantly being beaten down by people willing to bid on jobs for
next to nothing, then feel free to open your own firm.

 If you're a VP of Engineering, you're probably making 5 times what
your full potential of an Access coder is.  IMO, I'd rather have the
guaranteed paycheck (and the bonus you probably get) than the
aggrivation of trying to make a buck as a freelancer.

Peyton Manning
MVP