Shady's Speedy Sharpening System
by Shady (who else?)
This article first appeared as a thread on theWoodNet woodworking forum. It was compiled and reproduced here for easier public consumption. All Text and Images are the property of "Shady."
First off, as previously mentioned, there are 2 phases to any blade work: Grinding, which is coarse removal, and about getting the shape we want , and honing/stropping, which is getting the edge we want on that shape.
Here's my grinder:
It's a 10 year old crude German one, with a slow wet wheel and a fast dry wheel. Vibrates a lot, but this doesn't matter: the silver 't' shaped tool lying in front is a diamond dresser that I use to keep the wheels true and flat. The only purpose (with respect to sharpening) for this tool is grinding the primary bevel on a blade - nothing else!
This is my primary grinding set up:
It's an old 'eze-lap' diamond plate (at the front): I think it's a medium grit, and was purchased because it's cheap, and the rear plate is a solid steel japanese lapping plate. The carborundum grit for this is in the jars at the back - 90 to 400. If cost/simplicity is an issue, the lapping plate and grits would be the one I'd get first. Unlike a powered grinder, this gives controllability and finesse when trying to get a flat chisel back or remove rust pitting: there's also no chance of overheating a blade!!
After that, here's the honing kit:
From left to right we have; 3 Shapton stones (these are a new purchase, replacing traditional waterstones, which work just as well but need a little more maintenance), of 1000, 5000 & 8000 grit (professional series), a leather strop and green honing paste, a couple of different style honing guides (one of which can accept skewed blades, and one of which has a narrow wheel - these are the 2 key requirements), a 6" ruler, and a tankard which, when not full of fine beer, holds the water for the stone work, and doesn't shatter if dropped...
That's the lot: for this exercise, I took a 100 year old 'workshop abused firmer chisel that I inherited from my Grandfather - it's been rusting away and opening paint cans for years:
This is unusually bad (deliberately chosen to show what's possible with this simple set up). However, any brand new tool should receive the same initial treatment, which is about flattening/lapping the back of the blade. This is just as important as the front (sharpness being about the meeting of 2 sides, after all), and arguably more so for chisels, as the back has a guidance role when paring. For a new tool, you should be able to go straight to the 1000 grit stone if it's been prepped, but will need a bit of grinding if the manufacturer's grinding marks are visible.
With this monster, grinding is definitely required! Here you see 90 grit carborundum sitting on the lapping plate, in camellia oil, which is my preferred lubricant. (spritz the oil on first, then drop the grit on: other way leads to grit being blasted off the plate... )
Then I just press hard down on the top of the chisel and work it back and forth along the plate: I'm going hard enough to have cricks in my fingers when finished, but not insanely hard. The initial noise and feel is horrible: crunchy ground glass effect! As you work, the grit seems to get ground smaller itself, and becomes finer, with a mucky slurry building up.
For all stages from now on, the key point is to achieve consistency before moving on. By this I mean that, over the area of the blade you're interested in, all scratches must be of uniform size( and probably direction, which helps you check if you change working direction as you move up a grade) Here's the back after 2 minutes work at 90 grit...
We can see that there's some rust pitting about an inch back from the tip - that won't affect performance untill I've used this for about another 10 years (!), and a nasty scratch near the tip, which will - so back to the 90 grit again. It took me another 2 minutes to 'scour' that scratch out. At this point, you have a choice: work up through the carborundum grits, or switch to the diamond plate. With 'normal' initial jobs, I am able to go from this stage straight onto the diamond plate, and spend about another minute rubbing out the coarse grit scratches before moving to the stones. With this chisel, I worked up to 240 grit first, just to be happy that I'd achieved the best flatness I could. Exactly the same technique on the diamond plate (without the carborundum grit!) - a spritz of camellia oil, and work the blade across the plate, bearing dowqn fairly hard, until a uniform scratch pattern is achieved.
At this point, I took the chisel to the grinding wheel, and put a hollow bevel at about 30 degrees on - and that's the grinding finished. Total time on this chisel - about 5 minutes (I worked a little on the top and sides, purely for cosmetic reasons)
I then move to the 1000 grit stone. These Shaptons are a new purchase, and they really do cut fast. The technique is much the same: sprinkle of water, press down firmly and work the blade across the stone until a uniform scratch pattern is achieved. With thinner chisels, you need to be careful not to 'rock' the back at all, or you'll curve it. To avoid this, I push 'forward and back' with anything at, or smaller than, this one's size: the swarf pattern on the stone should give you an idea of what I mean:
On this stone it took me about 2 minutes to get a uniform pattern. It goes faster on the finer stones, because you're no longer removing significant amounts of metal - you're just polishing out the scratches.
This is the blade after about a minute on the 5000 grit stone: you can see the mirror image of the cement in it.
Next comes the 8000 grit - I spent about another minute here, and then moved to the leather strop. Charge it with the honing paste, and draw the back of the chisel across it about 10 times, with light pressure. You'll know that you're polishing, because the paste will darken. This must be done carefully with a chisel - you do not want to round the edge at all. I fold the edge of the strop over a bench, and draw the chisel back toward me, trying to stay absolutely flat until it has 'slid clear' into thin air.
At this point, you've finished a 'once only' operation on an antique or brand new tool: here's the results on this one: I spent a total of under 6 minutes actually working on the back, with another 15 or so mucking around with the sides and top, which are purely cosmetic efforts.
Now this blade will only ever need the next phase, which is honing the bevel, and once in a while re-establishing the main bevel on the grinding wheel.
For this, I just clamp into a honing guide: this is a firmer chisel, so I want my edge bevel at around 30 degrees, so I ground at about 26 - this means I've only got a little work to do. I literally spent 30 seconds rubbing backwards and forwards in the guide on the 1000 grit stone, pressing 'reasonably' lightly. All you need to see is a uniform change in scratch pattern across the whole width - you should be able to feel the burr on the other side. Then move to the 5000 and repeat: another 30 seconds. I then spent about a minute polishing out on the 8000, and then gave it 10 strokes or so (still in the guide) on the strop. So in 'normal' use, we should be talking well under 5 minutes for the whole operation from start to finish.
The results? It does have hairs jumping off my arm (can't show you the pic 'cos I don't have 3 arms..), and it shaves end grain pine cleanly. Focus is a bit off, but this pic shows the shavings I got off the bat:
This shows a glass smooth finish, and minimal splitting of the end grain at the ned of the piece (I was paring from right to left as you look)
The key, key, key point is achieving a consistent finish at each stage before moving on.
There ya go! And if I can, you can.... All comments gratefully received: now I'm gonna fill the tankard with something else...
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©2007 Cian Perez / www.CianPerez.com