Engineering workshop?

If there were a #tester_FAQ this would be question two. There isn't one right answer, and the shop I use is neither inside the M25 nor likely to be sufficiently interested in small one-off manual jobs to offer a good price to somebody not already an established customer.

The generic question is "Which subtractive metal working shop (milling/turning/grinding) should I go to for my prototypes?"

The generic answer has the following parameters:

1. Find somebody as local as possible
   
2. Find a shop where you can walk onto the shop floor through the open roll up shutter without an appointment
   
3. If the quote seems high, they probably don't want the job, so try somebody else who might.
   
   

Of course, if you don't have experience you might find it hard to judge what counts as a high quote. In the first instance, the obvious question on price is whether you could solve the problem a different way for less with COTS products. If there is no commercial alternative and you still want to do that one weird trick which nobody considers worth putting into production, I'd say bicycle scale parts (i.e. not so small that they need a Swiss lathe or so big that they need an Oil Country lathe) should not be more than £10 per cut for one set up. A simple plain bushing or spacer is 4 cuts (face, OD turn, bore, part-off), so there's your bare minimum for somebody who is doing it for a living rather than a hobby.