Lathe for sharpening lawn mower cylinder?

[pidgeon chit welder]

Check the cutting/sole plate is true and has not had a meeting between the cylinder and a stone before you attempt the insituation clean up.
I'd still go for the proper machine grind and a new sole plate though ( I used to cut the local bowling greeen with some such thing as a 32 inch Atco )

 

[metalspanner]

You will NEVER get a sharp cutting edge on a cylinder mower using lapping compound and running it in its normal cutting direction, they have to be backlapped on petrol mowers the most effective method is if possible put the drive belt into a figure of 8 drive pulley goes forward, cylinder pulley goes backwards.
Other wise its a drill (powerfull one) or a plaster stirrer connected up to drive the cylinder, you dont want to do this too fast or you end up removing too much metal and wearing out the cylinder and bottom blade quickly, ideally you should be backlapping after every time the mower is used and it would take no longer than a couple of minutes.

After working as a polo groundsman I know a thing or two about cylinder mowers especially sorting them out after hitting 0.5kg of horse shoe iron it makes a mess...

When you have a good sharp edge two things will happen, firstly you should be able to cut paper with no snagging or ragged edges, and the lapped cutting faces should be a dull grey, with no shiney spots on any of the blades.

As for doing cylinder and bottom blade grinding yourself I would not bother and leave it to the pros it is going to cost 30-40 vat inc etc to have it done, mess it up yourself and your looking at, at least 300 quid for a new cylinder and 40 quid for a bottom blade.