Just drafting some notes for my forthcoming demo. Will turn it into a web page
Woodwork tools basic sharpening the freehand traditional way
Part One
[Picture of pile of assorted edge tools, planes, chisels, spokeshaves, gouges etc etc. Other snaps to be inserted]
All these tools have one thing in common - in normal use for nearly all purposes their edges are sharpened at the same angle: 30º.
The sharpening process is the same - rubbing the thing up and down on an abrasive surface.
Doing it freehand is quickest, easiest and cheapest. It’s also the ideal fall back default system involving least kit and being most portable. Once you’ve got the hang of it it will do for 99% of woodwork ops. and will be your principle method.
Only one stone is needed though having two - fine and coarse, may help speed things up.
The synthetic double sided Norton IB8 or similar have been widely used for very many years, or natural stone alternatives.
Flooding the surface with oil helps float off the swarf which can be wiped off with a cloth. Any fluid will do but most used is ordinary light oil (3 in 1 etc) or white spirit or a mix of both.
1
How to maintain the 30º angle judging by eye.
Practice practice!! Get into the habit of visualising 30º. It’s half the corner of an equilateral triangle, it’s a third of a right angle. It’s the corner of a 30/60º set square. Practice drawing it by hand. It quite quickly becomes second nature but doesn’t need to be spot on anyway.
2
How do you avoid exceeding this angle in an attempt to speed things up (a.k.a. ‘rounding over’)?
Start the sharpening stroke at 30º and thrust the blade forwards but dipping it slightly as you go. More of a scoop action. The edge will not exceed 30 but the back of the bevel will be rounded slightly, but under the angle of 30º.
3
How do you know if a thing needs sharpening?
Eventually it becomes second nature and you suddenly feel the inclination to sharpen, but if in doubt do it anyway. You may be able to see light reflected from a blunt edge as a very thin polished line.
4
How do you know when to stop?
This is perhaps the most unfamiliar thing for beginners but is critical.
You don’t stop until you have brought up a burr or “wire edge” across the whole width of the blade.
You may be able to see this or feel it by sliding a finger over and off the edge (not ALONG it!!). If previously you could see a reflection from blunt edge it should now have disappeared.
5
What do you do then?
Next step is to remove the burr by turning the blade flat on to its face and rub it about flat on the stone. This may bend the burr back to the bevel side in which case you gently repeat the action in 2 above and turn the burr back and remove it. Sometimes takes several goes - just a few repeated gentle rubs on the bevel (at 30º!!) and then flat on the face.
6
What if a burr doesn’t seem to be appearing in stage 4?
This means the edge is probably very blunt and you need to remove more metal. Either keep going patiently or move on to a coarser faster cutting stone before reverting again to the fine.
7
What if a burr doesn’t seem to want to drop off in stage 5?
This probably means that the face is not flat enough and the edge/burr itself isn’t coming into contact.
Two solutions - A. the easy one is to lift the tool a tiny bit to form a very tiny bevel on the face side, or B more difficult is to flatten the face of a chisel for 20 mm or more, or a plane blade just 10mm so that the cap iron sits tight.
8
What about stropping and other finishing processes?
Stropping on a piece of leather helps remove bits of burr but more importantly polishes the bevel and/or the face, reducing friction where it is likely to be greatest in use. It can make a noticeable difference, depending on what you are doing.
Part Two pending
Camber, holding devices, non flat stones, finer stones, other problems etc
