Whilst looking for tables of tolerances and fits for my clock spindles, I stumbled upon Mitcalc.
This is a series of Excel spreadsheets that simplify engineering calculations. The sheets provide a simple interface to select and enter parameters and displays the results in the form of numbers and graphical displays.
For the fits, this allows you to select the type (clearance, transition or interference) and recommended fit along with the diameter of the shaft or hole. It then provides the minimum and maximum sizes for the components. I found the sheet easy to use but you do need to know what to enter so its not a magic solution and you will need to read up on your theory.
The modules are reasonably priced if you need on or two and it’s possible to buy an annual or lifetime license if you need several of the 30 mosprings and bearings. There are a wide range of topics such a belts, gears, springs These come with 2D export capability but for 3D support you will need to pay a bit more for license.
I tried the spur gears module with Libre Office and it could not handle the complex VBA macros in the spreadsheets, so you are going to need Excel to make this work.