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Thursday, 28 October 2010

Supersize Me!

The new 12mm, 14mm and 16mm Narex mortice chisels arrived the other day (along with some new sizes of the Narex bevel edged chisels) and being an inquisitive sort I had to have a play!

I had expected the 16mm mortice chisel to be a bit of a brute to wield, it is after all an enormous chunk of steel, but in its working position the weight is all borne by the workpiece. Making the initial cuts with the blade pinched low down between thumb and forefinger, you can feel the chisel start to 'swoon' if you get too far from vertical, when it feels weightless, you know it's perpendicular.

The intial cuts suggested that making progress wasn't going to be a problem, 3mm at a time into English walnut with nothing more substantial than a sharp tap with the mallet.

Having cleaned out the first layer of chips to create the shoulders of the mortice I moved on to heavier blows and the chisel just ate its way in. A handy tip I picked up from Jacob Butler is to chop through the waste rather than trying to clear it as you go. This saves a bunch of time and preserves the shoulder as all the force is going downwards. The chips gradually get more and more finely chopped too, so most of them will fall out when you turn the workpiece over and give it a sharp tap on the bench, especially if you made a cut lengthwise through the middle of the waste with a broad bevel edged chisel first. What little did need levering out at the end was done by using the kevlar reinforced head of the clamp as a fulcrum, again to preserve the crisp finish.

Considering that this was all done with the factory finish on the cutting edges I was pleasantly surprised and impressed with both the efficacy of the tool and the results. A little judicious honing of the primary cutting edge and the first inch or so of the sides will no doubt yield further performance.

If you haven't tried cutting mortices by hand I can thoroughly recommend it. Morticing machines have their place and if you are doing production work they are invaluable, but if you are only doing a few slots to cut then chiselling them is a quick, inexpensive and rewarding alternative.

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