How to control the speed of a lathe

[clockboy]

I have purchased one of these I presume it will work. It is a "3500W 10A Variable Voltage Controller Copper For Fan Speed Motor Control"

[AndyHull]

It will probably work, but that isn't a standard UK socket on the top, does it come with some kind of adapter?

If it comes with a "UK" plug on the end of the cable, then I can almost guarantee that it is one of those weird Chinese ones with no fuse in it. In which case, cut off the plug, fit a real UK one with a 10A fuse in it. 

As to what you plug in to the top of it, if it doesn't come with an adapter, then fit a travel three pin adapter, Indian/Chinese plug to UK socket, so you can plug your existing plug in to it.  If you use a two pin adapter, you loose the earth.

Speaking of which, I would be interested to see what it inside that box. I wonder if they bother to pass through the earth wire. 

Time will tell. Crack it open when it arrives, and post a couple of pictures.

[clockboy]

I did notice that I will use a travel plug adapter. The picture showed it being plugged into a normal UK socket. So as you say just wait and see but for £8 inc. postage I have not made a huge risk investment.