You may need to grind off any casting flash first, but you have a margin to spare.

You will also need to use something like a left-hand tool mounted lengthwise in the rear slot of the toolpost to reach around the rim of the flywheel.

Keep the revs low, and don't run the lathe for too long without a break for a cooldown.

Neil

Would not worry about any crust if present using inserts, 10thou should be OK but I'd be at about 400rpm

Even on an industrial lathe some fiddling is required to machine near capacity. This flywheel is over 2" smaller than the listed capacity in the gap, but look at the overhang on the top slide, along with a LH boring bar:

Andrew

I would have thought there is little point in a seven inch lathe not being able to machine a workpiece of seven inches diameter? Inevitably the outside rim will need to be cut with a tool protruding at least the width of the rim – unless the rear tool post possibility is miraculous?. Either the tool or the post has to clear the edge.

I would have thought that the casting may need cleaning up a bit to clear the bed, but then just slow-going around the circumference.

Is the lathe truthfully specified as 180mm ‘centre height’ or ‘swing’? There will be a very slight difference.

Assume you are going to use TC tooling? The recommended surface cutting speed for HSS is likely less than the minimum for your lathe – and I would not want to be using one of their variable speed drives at, or near to, the minimum rpm, without extra cooling, at any sort of loading and sensible machining time.

I was just looking at the new specs – for a chester db7vs – they quote 50rpm as minimum. Warco quote zero for the WM180 (0-1250? On ‘lower speed band’. Not much else to comment on. Still would not load up the motor at slow speed without extra cooling.

My lathe will go down below 40rpm at the spindle with the motor running at 50Hz, but I would not want to work it hard for any long time at below 25Hz, although it will run happily much slower on light loads, at least for short periods. I reckon my lathe is far more resilient to low speed operation than any chinese option.

Working at max diameter you may well find the machine just stalls at 50rpm, different if you are running that speed and say threading M6 where the diameter is much smaller. That is why I advocate 3-400rpm and not too deep a cut. My 280 will happily do 10" flywheels at 300rpm but just comes to a stop if I take the same DOC at 50rpm, Brushless and inverter versions are better but may still be stalled.

There are other ways. If say you decide on something with a 10 in flywheel will you feel obliged to get a 10 in lathe? Apart from the, rather unnecessary, height raising designs that have been around for years you sometimes need to get out of the mindset of using the lathe only as it was intended.

How about making a jig to ensure a true hand drilled hole in the centre. Then mount on a spigot on the cross slide and slowly turn by hand against an end mill or flycutter in the spindle. Think of your lathe as a general purpose mounting system with some parts that can be moved precisely and other parts that can provide rotating motion.
If you did want to run it as 'normal' but are concerned about low speed torque use the flywheel itself as a pulley rigging up your electric drill at the front such that the belt leaves a gap where the tool is cutting.
Generally get more adventurous.