You need to work out the steps per unit, as you are set up in metric a unit is 1mm so you need to find the steps it takes to move 1mm, in other words divide the inch values you have above by 25.4

Hood

Many thanks for your help i will try that tomorrow and see how i get on.
I can do quarter steps and eighth steps which will be the best do you think
 

I would go for 1/8th step, you should get much smoother motion and better resolution. You will however need to alter the steps per unit again if you do that, you would need to divide the inch values you worked out by 25.4 then multiply by 4,or if you already have the steps per mm set  just multiply by 4

Hood

Ive done as you said(apart from the steps ive left them at half steps and ive done a quick test cutting out a 100mm x 100mm piece of aluminum board and its great i havnt allowed for the tool diameter as yet,there maybe a way of doing it in mach3 but not found it yet so i have just added on the diameter of the cutter (when doing the gcode)to get to the size i require but on a whole it seems great.
I do keep getting the mach3 software resetting all the time it might be cutting for 20 secs or a minute but it does reset.I only have a push button reset at the mo i havnt put on my limit switches as yet ,the motors arnt getting hot they are warm but not too warm and if i turn off the drivers and motors it doesnt reset so maybe its a wiring problem but thats  for another day
many thanks for your great advise and hope to ask you more questions soon
regard
kevin 

Likely you are picking up noise on the E-Stop input, best to have all signal wiring properly shielded and grounded but as a stop gap you can try increasing the Debounce Interval on the General Config page, try 2000 and go lower if you can.
Hood