Some Observations on Chisels

 

An assortment of Chisels: Anant Mortising chisels on top, Chinese made chisels with wooden handles, plain black handle Stanley chisels (bottom left) and black and yellow handled Stanley chisels (bottom right)

There can be nothing more distressing than the dull thud of a mallet striking a chisel that will not sink into wood. I dread that sound and know that my chisel requires urgent sharpening or worse re-grinding. Fortunately, sharpening is no longer the dreary chore it once used to be, thanks chiefly to a few techniques I have picked up along the way.

But first, a little bit about chisels available in India. From my experience, there are about three kinds generally available: the cheap, soft steel ones which are usually China made these days; the tough, Chrome Vanadium Steel ones made by Anant in Ludhiana; and an assortment sold by Stanley, mostly China made ones for the Indian market.

All three are very usable but have to be prepared before use. I have found that all three types require considerable work initially because for a chisel to cut well, the first requirement is to flatten and polish the front face. Once this surface is perfectly flat, then the bevel can be sharpened and kept sharp without a lot of effort. But the initial flattening in my opinion requires quite a bit of time and patience.

However, this task too can be shortened by only flattening the last one inch or so of the chisel front towards the blade. To find out how much abrading would be required scribe some lines along the edge and then rub it against the sharpening surface a few times. The lines that don’t get rubbed off indicate a depression and the area around it would have to be worn down to wear the area down to a uniform level.

Edge is depressed and needs to be made level

In the photograph above, it can be clearly made out that the edge of the chisel face is depressed and the rest of the blade slightly raised, jutting towards the edge in a convex manner. Patient abrading would be required to flatten this.

I use the word abrading to mean wearing down a surface or edge through friction. This involves rubbing steel on sandpaper, or stone, or diamond plate and so on. Abrading takes off material and gradually but imperceptibly diminishes the steel. Grinding, on the other hand, is a much more aggressive action, usually undertaken on a grinding wheel, which takes off a lot of material quickly, usually on the bevel edge of a chisel. Grinding is a difficult business and I won’t venture into that. Finally, there is polishing which involves virtually no material removal but imparts a shine to a surface by making extremely fine scratches on it.

The easiest chisels to sharpen are the carbon steel ones made in China and by a number of manufacturers in India as well. These cost no more than 30 or 40 rupees each and a full set can be had for just about Rs 100. These chisels are not milled very well and would have a lot of scratches especially on the back but that does not matter much. 

A Carbon steel chisel can be sharpened quickly and easily

It took me just a few minutes rubbing on sandpaper to flatten the edge of this ¼ inch Chinese chisel. I find this chisel extremely useful because all it needs is a few strokes on my diamond plates to sharpen. They lose their edge quickly but who cares, for they cut well and are extremely sharp. It takes but a moment to re-sharpen them.

Anant mortising Chisel: Good but brittle

I bought a couple of heavy duty Anant chisels for cutting mortises, one ¼ inch and the other 3/8 inch. These chisels are well made, heavy and solid. They are made of Chrome Vanadium steel, which if heat treated properly is said to be strong, tough and resistant to wear and fatigue. It is considered way superior to simple carbon steel and is used in a lot of industrial applications as well. However, I was disappointed to find that the steel gets nicked easily and initially I thought thiswas due to faulty production processes. But that is not the case, Vanadium Chrome Steel, I learnt, has the advantage of being rust resistant and hard but is also brittle and difficult to sharpen. Vanadium-Chrome steel chisels like the ones made by Anant are good but are best prepared on a grinder.

I liked the feel of these Anant chisels but was disappointed to find a deep nick on the edge of one of the chisels (see photograph above). To flatten this would take hours and hours and the edge is best reparied on a grinder and then polished. Once polished and sharpened, these chisels work well and for the price (about Rs 200 each) appear to be worth it. In the end, the user must evaluate if it is worth all the time required to keep these chisels well maintained and sharp.

Back of a Stanley Chisel: Edge is not flat

As for the chisels Stanley sells in India, for one, they are more expensive than Indian or Chinese made ones and just do not seem that superior to those made by Anant, except in the quality of steel. In the photograph above, it is clear that the face of this Stanley chisel has been poorly milled and the leading edge is depressed. This again will take a lot of work to flatten because these chisels too are made from a very hard variety of steel. I suspect that the Stanley chisels sold in India being much cheaper than the ones sold in the US and EU markets are made in China. This must be true of other Stanley products sold here because they all seem to lack finesse. 

There appears to be two types of Stanley chisels sold in India: one with black handles and the other with more solid black and yellow handles called DynaGrip chisels. The latter are far superior to the plain black handle ones. The black and yellow handle chisels are often perfectly flat on the back and often require very little work to prepare. These are by far the best kind of chisels I have come across in Indian stores. However, once prepared, both types of  Stanley chisels seem to retain an edge the best and the steel does not chip off or get nicked easily. 

Face flattened after some hard work

There are two other points to consider about the cheap Stanley chisels sold in India. First, they are cheap and, in my opinion, excellent value for money. The better quality Stanley chisels, such as the “sweetheart” series cost over US $ 150 for a set of eight as compared to just about Rs 300 for a set of three in India. Second, in the long run Stanley chisels sold in India wherever they might be made are extremely good value for money and keep an edge for a much longer time as compared to the other chisels. The black and yellow Dynagrip Stanley chisels meant for mortising work are even better and once prepared work extremely well. The superiority of the steel used in Stanley chisels is unquestionable.
 

Bevel of chisels

At any rate, it would appear that all chisels need to be flattened and polished. Once this is done, the next step is to polish the bevel. This requires a little more effort as the chisel has to be held at an angle (usually 25 degrees) and then rubbed against the abrading surface. Experienced woodworkers can do this freehand but most beginners would be better off using some sort of guide or jig. The bevel edge has to be abraded till it forms a sharp edge with the flat face of the chisel. At this stage a burr would have formed on the face edge; a fine burr can easily be felt and removed by a few strokes on the abrading surface.

Green Buffing Compound

To impart a final polish and make the edge razor sharp some master woodworkers recommend the use of a polishing compound. The green one is the best and is easily available in many hardware stores. It costs about Rs 100 and is generally used in conjunction with a cotton buffing wheel on a grinder. However, a piece of cardboard, the coarse kind used at the back of writing pads, will do just fine. Rub some of the compound on the cardboard and then forcefully rub the bevel edge against it. The green compound will turn blackish as it rubs off a fine layer of steel and leaves a mirror polish.

Now any chisel, cheap or expensive, is ready for some serious cutting.

I buffed the back of this chisel just for the heck of it; looks shiny and really nice now.

 TIP!
 New chisels are often covered with a layer of oil or some kind of lacquer to prevent it from rusting. When you buy a new chisel make sure you first take off the oil or resin in which it is covered before you begin sharpening it. Otherwise your sharpening stone or sandpaper will clog.

Indranil Banerjie
7 May 2013