[ soundtrack : Swingrowers - ‘Via Con Me’ (It's Wonderful) ]
If you need to make more than a dozen mortises on a regular basis you might get tired of chopping them by hand (or routing or paring out rows of drilled holes), not to speak of the time spent individually marking and fitting them. In that case, a hollow chisel mortiser is a useful helper. It needn’t be an expensive, floor-standing model, a bench-top version will serve well for most furniture-sized work. I have two: one metric, one imperial. I’m bilingual :-)
This means I need to have two sets of tools:
I’ll stop bragging and get to the point now: You’re probably aware that you can sharpen drill-bits and augers, but did you know that you can also sharpen the hollow chisel on a mortiser? It improves the performance of the mortiser appreciably, especially with harder woods — the cuts are cleaner, preciser and more effortlessly made. You’ll need a tool like this:
Diamond-coated ‘countersinks’ - fine & coarse. I bought mine from Axminster (UK) but they are made by Lee Valley so should be readily available on the other side of the big sea, too. In use, you chuck them in a drill press, and hold the hollow chisel upright by placing it in a block of wood, like so:
Give it a drop of oil to help the swarf swim away, and use low speed and light pressure! The diamonds are hard, but they’re not that strongly stuck to the substrate, so if you bear down on the handle you’ll just shear them off the cone. This holds for all diamond-coated sharpening implements: light-to-moderate pressure is all that’s required.
Centre the cone carefully and be patient!
After a while you can feel a burr on the outside; perhaps not all the way up to the tips of the points… but still, better than it was! Next step is to hone that burr away, like you would on the back of a normal chisel.
You can also improve the bite of the drill/auger by filing it sharper. In these pictures I’m sharpening the smallest size drill, so I’m using one of my ‘needle-files’. At trade school we were encouraged to buy a set of them to fettle and dress bronze hardware for furniture. I still have them after 30 years :-) On larger sizes I use saw-files or diamond-coated paddles, whatever suits best.
If you’ve never tried to sharpen a drill/auger before because you’re afraid you might spoil it: Find a rusty, old, dull drill so that there’s nothing at stake and go at it with whatever small file you’ve got! It’s not at all difficult, you see … press the tip down onto your bench to keep it still and just use your good sense. Keep track of the ‘shininess’ of the steel because that’s what tells you where you’re filing (or you can blacken the steel with a sharpie to make it obvious where you’re removing metal). You’ll almost certainly make it sharper.
If you’re interested in sharpening woodworking tools I can do no better than recommend “The Complete Guide to Sharpening“ by Leonard Lee. It’s very comprehensive, clearly written and full of pictures and graphics — one of the best and most useful woodworking books I’ve come across.
A sharp cutting edge is where woodworking begins.
This might push me to try sharpening some of my duller bits...