For nozzle diameter I just use 1" its not really that important to have an exact value here. It is used for clearance around possible tip ups.
Kerf width is variable based on your individual machine (though we have the same make an model it can still vary), consumables you are using and the age of the consumables, material type and thickness and cutting speed. I’m sure there are more I am leaving out. All this to say that any value you use will need to be verified on your particular application which will change sometimes even during a cutting session.
Most people I think start with the .055 value from the Langmuir videos and go from there.
In my experience (which isn’t much) if you add 0.01 to the orifice diameter it will get you close then test to get the actual kerf width.
If you are just doing artwork and you don’t need it exact you could use the 0.01+the orifice without all the testing… but I think its a good exercise either way.
Note: Don’t exceed the tip power rating. ie. if cutting at 35 amps use a 40 amp tip
This was posted by @mechanic416 related to different tip sizes.
This is what I have found to work with most plasma cutter nozzles/tips that most people have in their shops or garages. NOTE: Orifice hole size 1mm = .03937"
20 amp tip - 0.6mm/.025" - 15 to 20 amps - 50 to 55 psi
30 amp tip - 0.8mm/.030" - 21 to 30 amps - 55 to 60 psi
40 amp tip - 0.9mm/.035" - 31 to 40 amps - 65 to 70 psi
50 amp tip - 1.0mm/.040" - 41 to 50 amps - 65 to 75 psi
60 amp tip - 1.1mm/.044" - 51 to 60 amps - 65 to 75 psi
70 amp tip - 1.2mm/.047" - 61 to 70 amps - 75 to 80 psi
80 amp tip - 1.3mm/.051" - 71 to 80 amps - 75 to 80 psi
And this is a good kerf testing procedure from @TomWS
Screw all the bogus advice you’ve gotten. Cut a 2-3" square. Use any kerf setting you think is close. Measure the resulting square. It’s error from 2.0000" is the error in your kerf setting. Adjust the setting to 1/2 the error (+/-) depending on whether it’s an inside cut or an outside cut.
This is not rocket science.