Changing String Gauge

I’m planning on eventually changing my gauge from 45-105 to 45-100 will I have to get my nut filed?

No because the 105 refers to the diameter of the string (0.105 inches thick).

You’re changing to a slightly smaller diameter string (0.100 inches thick) which will sit in the nut slot just fine.

If you were adding thicker strings then you might need to file the nut to accommodate a larger string.

Make sense?