The R8 20mm gear cutter arbor I ordered from Ali came yesterday. I'm hoping the Modulous 1.25 cutters come shortly. If yours are 1.25, you would be welcome to borrow it. I also have an MT3 arbour that takes 1" cutters and a large box of miscellaneous cutters for my mill drill if that works better.
There is a great discussion on @cuslog
's thread here:
A few pages before the end, @John Conroy
discusses making his own arbor and cutting two gears. It's a good read.
Thread 'King 1440 and Craftex Threading' https://canadianhobbymetalworkers.com/threads/king-1440-and-craftex-threading.7096/