Tim, NDIY, Michael and Gordon, thank you for your replies.
Tim- my apology- I (wrongly) presumed that Irvine parts would be recognised by name within this online community. My fault, I should have been more accurate, I'm sorry.
NDIY- you are quite correct, however, mixing imperial and metric meaurements only cooks my head, and will, I'm sure lead me to make further errors. I personally prefer to work in metric and units of 100 if possible.
Michael- spot on- that's exactly what I'm looking to have made. They'll need to fit tightly inside a bearing, which is pre-made in mm. The solution I have at the moment allows for more 'play' (if that's the correct term to use on a highly specialised engineering forum) than I'd like- that will lead to innacuracy during the device's measuring process.
Gordon, thank you. You are so very close, in fact almost a debatable line cutter (sorry, archery term). For reasons of commercial sensitivity right now, I'm really sorry, but I can't disclose here what the measuring device will actually measure. Once it's gone into production however, I'll be showing you all, for sure.
There's also been a couple of email replies received (thank you to those that sent them), but to read them through in full and reply in detail, I'll need to be at the office, tomorrow.
Lastly, I need a dictionary- my spelling in the title is very poor.
Off to sit on the naught step.
Thank you all again.