OK. So you can sharpen hoes. What about spades? And can I sharpen my garden shears myself? (How?) And what about secateurs? Absolutely all advice welcome. I have a sharpening stone - rectangular. Back to basics here! What needs sharpening and what doesn't!
PS It's cold and wet here so I might as well sharpen something!
Spades: just like hoes, a flat file. Garden shears, clean first to get rid of dried sap (which would choke the surface of the stone), then use the flat stone, course side first then fine. If you look carefully, you will see the existing angle that needs to be honed. It helps if the blade is held in a vice to keep it steady. Secateurs - different for anvil type/bypass type, and needs greater care, and finer stone. Again look for the existing ground angle as your cue. A lot of secateurs have blades that can be removed for sharpening. Sickles are straight forward, but scythes are a special case involving specific peening tools and very fine whetstone. Note, for all these tools avoid using a power grinder/angle grinder, as the heat can mess up any heat-treatment that has been applied to the tool.
Your rectangular stone is likely to be an 'oil stone' requiring regular application of light oil to prevent surface choking. It can either be use flat on a bench (good for things like pocket knives) or hand held and used just like a file (e.g. to sharpen the blade of a hedge shear held in a vice).
Fine metal file will deal with secateurs..they just need to be cleaned first.
I spray WD 40 or something similar.. generously, all over the metal parts..let them 'soak' for few minutes and then most of the 'muck' will just scrape off (or use some sort of abrasive paper/steel wool). You can see the angle on outside of the blade..and shapen this with file...don't do insides as this will create gap between blades and then they won't cut!!! If you get little fit 'burr' on inside edge of the blade..just light 'lick' with file will take it off and that is all what is needed.
Same rule for shears...the don't sharpen from inside edges of the blades..they need close 'contact' to each other for cutting!
Metal file don't usually work for secateurs..or it is hard work. You need something more 'robust'. I usually use angle grinder and again..keeping to the original angle of the edge. If you get it right...you only need to do it once a season (or so), as even with regular cutting..just lighter touch with stone will keep well made edge sharp and maintaining is easy peasy!
Spade...depending what is made of. Old type spade..yes..they are brilliant if kept maintained and with sharp'ish edge..but then they need 'oily rag' treatment regularly too to keep rust away. Modern stainless steel spade...nope..I haven't sharpened any of them, they are pretty much maintenance free and I don't find sharpness necessary if I dig on ground that is not that compacted anyway. If you need to cut turf with spade....good sharpness is required for neat edges.
Like Ian mentioned....scythes are more complicated and that is skill that you need to learn to do properly, should you need it, and with proper honing tools.
I'm bit of 'sharpening geek'...love doing it when Its needed..most useful sharpening implements for gardening tools for me are course/medium metal file for 'rough' jobs and fine chainsaw file for more refined touches...other things like stones (different grades) I tend to use much less.
There is oil stones and wet stones...the name will tell you what is used for lubrication when sharpening. Idea is that the stone with correct lubricant will make kind of 'paste' that will do the sharpening.
Thank you for your advice. I'll get sharpening!