Keep in mind you do not want to cheap out on certain things. Cheap taps are OK too a certain point but if they break you may lose whole part. We have a machine shop and YES there is some areas you can cut corners. Look at MSC https://www.mscdirect.com/browse/tn...e-Taps?searchterm=metric+tap&navid=4287643437 This is where we get our machine tools from. If you are just going to be doing it by hand stick with 4 flute style. If you want to power tap in a mill and 2 flutes work good.