Hi Mark,
as Mick says, this is as contentious a topic as you can get round here! Mick: I was typing this as you typed yours so I thought I wouldn't waste it!
. . .
Don't take this as the only way to go, by any means, but it's a cheap way to get really good edges - Google "Scary Sharp".
Basically you need:
- a good flat surface, about 1ft by 2ft (I use a thick bit of glass, but clean MDF is also popular),
- some spray glue (Scotch "Spray Mount" works for me),
- a honing guide (the Eclipse copies are cheap and work pretty well for most blades),
- a cup of water and a teaspoon, and an old cloth to clean the blades during the process,
- and a selection of _good_quality_ wet and dry paper, from fairly coarse, going down to really fine grades (2000 or 2500 grit).
First you need to flatten and polish the backs of the blades you want to sharpen. You only need to do this once, and although you need to do it once, I'll come back to it (it'll make sense, honest!).
Here's what to do:
- Cut some strips from the wet+dry, a selection going through the grits from coarse to fine, each wider than the widest blade you want to sharpen.
- Stick them down to the surface with the spray glue in parallel strips in order (I label the grit side with felt tip pen in one corner, so I know which is which).
- Set your blade or chisel in the honing guide.
- Start with the coarsest paper. Use a few drips of water from the handle of the teaspoon as lubricant and hone the blade on the one paper until you can see it's abraded the bevel evenly.
- Strop the blade gently (I use the thigh of my jeans usually, but don't tell my wife!) - this removes any wire edge build-up.
- Clean the blade with the cloth. This is important as you want to stop coarser grit and filings from contaminating the finer grits.
- Move to the next grit down and hone gently until you can feel the roughness has gone.
- Clean and repeat step 5 onwards.
When you get down to 2000 or 2500 grit, you should be able to dry-shave your forearm or the back of your hand, and the blade should be "scary sharp." It's almost idiot-proof (it works for me!).
In regular use you can quickly pick up from one of the finer grits to keep the edge you're using from dulling-off too fast.
Flattening the backs: This is crucial, whatever system you use. You take a similar approach to the actual sharpening, but rub the flat, non-bevel side of whatever-it-is on successively finer grades of paper until you get a mirror finish, or close to it.
You only need shiny flatness on the business end, not the whole blade. It's hard to do when the paper is laid out in strips, as one gets in the way of the next and so on - you really need the paper stuck down next to the edge of your flat surface, not in strips across all of the area. This is why I mentioned it separately.
It's a one-off process - once the back is flat and mirror-smooth, it's done forever. It's necessary, as the smoother it is, the more sharply defined the business edge of the blade is. Unless you do flatten, you will get disappointing sharpness.
There are other methods that you can 'just do' without much practice, notably the electro-mechanical wet grinding (Tormek-type) systems, They work, but in my experience they're a bit hit and miss, there's a lot to go wrong (technique, I mean), and you can grind through a lot of material just practising.
Which reminds me: start with an old blade for practice, if you have one, as it will matter less.
You'll be truly amazed what a difference a really sharp blade makes. I've a friend who manages a joinery workshop. He's not a woodworker, and we've done some stuff together partly so that he can learn-up on what his team are doing. He was planing some English Oak a while ago, by hand on my bench, using a #5 and my #7 (for fun - it didn't need to be that straight!). He got a bit stuffy the first time I got him to stop and switch blades after about ten minutes. So I let him go on for twenty, then gave him back the one I'd just touched up with Scary Sharp. Instant convert! The touch-up only takes perhaps 2 mins of interruption (you can usually start on 1000 grit), but the difference in keeping the blade really sharp is amazing.
There's lots more to this. Jacob will tell you all about the value of cambered (curved, not flat) bevels and doing things freehand. He's not wrong, but I don't have the muscle control for it these days. For me Scary Sharp is cheap quick, was easy to learn and is repeatable.
Whatever you end up doing, have fun!
E.
PS: The best wet+dry I have came from Axminster. The cheap stuff (from Toolstation) was way too curly, a bit uneven, not available in really fine grades, and wouldn't stay stuck down). Start with some good quality wet+dry to avoid disappointment.
