Here's the options on ebay. The sewing machine shops may have other items I don't yet know about. I will look into those in coming days.
The gear reduction option above, is available in USA. Including postage it is $433 AUD.
This next type is $190 AUD, including postage. To me, this option doesn't look sufficiently heavy duty to last the distance. The base just seem strong enough to take the strain of a couple of well tensioned belts. I may be wrong, but it's a lot of money to spend on the off chance.
This motor is same type as mine is, but it is only half the rpm. That's a 50% decrease straight off the bat, and may be slow enough for me. The auction for this motor had no Buy It Now price, and if no-one else outbids, it would cost $70. Another similar motor has Buy It Now of $295. It is in Australia (Vic. to be exact), but shipping cost not stated.
This is a speed reducer similar to what was recently mentioned. It is listed at $32.24 AUD, with Free Postage! It comes from Hong Kong, and I have concerns that this sort of device may damage the motor, as I have not found mention anywhere reputable, indicating this mod is an option. If it was a good option, surely somebody somewhere would be spruking the virtues (other than the seller!) I would be very reluctant to try this device without getting the nod from a qualified electrician who is familiar with all the possible outcomes.
This is the kind of motor I was thinking of buying in the future.. It costs $440 AUD, including postage from within Australia. The postage component is actually $18.10. It is a 750w motor, and is speed variable, though the listing does not state to what degree. One of the eBay images shows the data plate on motor, and it says output is 550w, not 750! What IS STATED is that sewing machines with an oil pump (which mine is) should be "run at higher speed on a regular basis to circulate oil". This is something I hadn't thought about, and adds another dimension to consider.
I would not be comfortable with making my own speed reduction device. My welding and engineering skills are very limited. The reality is, I could do more harm than good, and there is a fair chance of that being the case. I'm just not that talented.
The 3 phase thing sounds scary, and a lot of work that I don't want to go to. Far too lazy to reinvent the wheel, or in this case...the electron. I don't mean any offence by this. I'm just not anywhere near as talented as some of you folks are. I need to keep things simple. Sure, I can put a coat of paint on a panel, and apply body filler as well as anyone (though I HATE panelbeating), but on the really clever things I'm often out of my depth, and I need to acknowledge that, so I don't do damage. Eg: My welding has the ability to replicate, in hot metal, a very close resemblence to human vomit, only on a smaller scale! I'm getting better, but nowhere near good enough to weld structurally sound. Therefore, I get someone else to do that for me, then I don't have to worry about catastrophic failure of my own cause.
Getting back to electrons: Two atoms were walking down the street, when one suddenly stops and looks around, then says Oh My, I Think I Have Lost an Electron. The other atom asks Are You Sure? To which, the first atom says, Yes....I'm Positive!!
Why is nothing ever easy?