Scythe grass blades require an anvil and hammer...
They sell one that is made to be stuck in the ground so you can peen the edge w/ a hammer...
We had an oval shaped stone +/or just used an 8 mill bastard file after standing the halft up on the stub end. This was using Austrian grass blades & my pappy would always tell dad he was doing it wrong...
I always had a patch of poison ivy on my left wrist from holding the top of the blade w/ my left hand where the leather work glove stopped & my wrist touched the 'juice' on the blade while I was filing w/ my right hand.
I don't like using grindstones for anything with a cutting blade unless it is to just redo the angle and then only to get close. They remove too much metal, are to hard to get the correct taper without being wavy, and have too much potential for getting too hot and taking out the temper. They are great for making something new and removing excess metal though.
I use a square hand whetstone on most of my edged knifes, scythes, etc. There are several of them of various grits so depending on the job, I'll pick the one which seems best. Chisels have a holder which holds the blade at a steady angle to the whetstone but for the rest it's mostly done by eye and feel. Kitchen knives get a steel used after the whetstone. We have a treadle operated grinder as well as an electric grinder and they are used to sharpen the cruder edges such as those found on shovels and hoes.
Sythes and drawknives. Is it any good for that? I dont know what type of stone it has on it, I would say that its not much abrasive at all.
The hand crank grind stone and foot pedaled types (large wheels) were used mostly for axes and weed hooks,n' kaiser blades (sling blade)large butcher knives or initial edge on smaller blades and chisels..Most had a tin can hanging over them that you poured full of water and it dribbled on the stone as you cranked and sharpened...made the stone cut better and if you could have cranked it hard enough to get hot, it would have prevented the heat build up..
Dad usta tell about cranking the stone of granddads when he was seven years old(1924) they charged timber workers a few cents for using the stone and it was Dad's job to crank it for them...Talked about this one old feller that would sharpen his axe and try to press it so hard against the stone to stop it's motion as he was cranking...he was kinda proud that he couldn't stop it, but dad said it wasn't because the old feller didn't try..
Look around for one of those little diamond rod sharpeners. Mine was couple bucks or so and basically plastic handle that holds two diamond dust rods at an intersecting angle. Plastic does good job protecting your hand. Has one slot for double edge and one for single edge. Works fairly well. I use mine mostly for kitchen knives and scissors, but no reason it couldnt work on a scythe or drawknife. Its by far best/easiest way I've found to sharpen stainless steel cutting edges on cheaper knives. Not best way for traditional high carbon cutting edges, but sounds like you are looking for cheap and quick, not best way. I got mine at A2Z but think I've seen simular at Wallyworld. Its cheap enough to be worth a try and not feel bad if it doesnt do what you want.
"What would you do with a brain if you had one?" -Dorothy
"Well, then ignore what I have to say and go with what works for you." -Eliot Coleman
I have an old foot treadle powered stone. It may not be "the" thing to use these days but I can assure anyone that would try one that they are darn handy. For things like axes, hoes, shovels, etc. they do the job much faster than a file and better in some cases. An old tool, but one worth having if you get a chance at one.
Does it have a water tub below it? Is it a wetstone wheel?
Dad always used his to sharpen the sickle mower blades & his sythe. Worked well for him. They are a very fine stone. He put a electric motor on it. Actually had it on the jackshaft for years, then got rid of that & put it's own motor on it. They turn slow - you can touch it with a finger without damage - not for long, but....
The water is important. Don't use it without the water. And slow turning.
Think some here are thinking of a coruser dry wheel - which maybe is what you are looking at too?
The slow wetstones were designed for this sort of job.