Tuesday, January 13, 2015

Restoring and sharpening a chisel

I got an 80 year old chisel handed down from my grand father, which is made out of really hard good steel.  It hadn't been used for decades so it wasn't in a great condition.  This is how I restored it.

The metal had come off of the handle so I used a good dose of epoxy to glue it up in place.  I cleaned the blade with a series of dry wet super high grit sand paper and then buffed it with my dremel.  I didn't take pictures of that.

One that was done, I set out to flatten the back, reset the bevel and sharpen it.

This method also works for setting up any brand new chisels you'd get from the store.

To flatten the back I use wet dry sand paper at 350, 800 and 1500 grit.  These are fixed to a piece of scrap glass using double sided tape tape.  I spray those with window cleaner.

This particular chisel's back was pretty uneven so I actually spent some time on the coarse diamond stone before this.

In this picture you can see it half way through:

And this is once it's completely flattened:

To reset the bevel I use the veritas mkii jig, which is a bit pricey but awesome.  I had tried doing this by hand and ended up with a convex bevel.  Then I tried a cheaper jig, which didn't work very well for me, so I finally went for the veritas.  It was worth the money.

Here I am setting the bevel to 25 degrees:

I use coarse fine and extra-fine DMT diamond stones, also with window cleaner:

This is how the bevel looks almost finished:

The veritas jig has a neat feature to add a bit of a micro bevel by just turning this knob:

After that I do a couple of passes on the back to remove the burr:

I made a quick stropping board with  piece of plywood and a piece of leather glued to it.  I rub chromium oxide on it and then give it a few passes to finish it off.

My favorite way to test and make sure it's as sharp as I need it is by cutting a piece of paper.  It should leave a super clean cut with very little effort:

You can also try and get some shavings off of a piece of hardwood end grain.  This method definitely makes the chisels as sharp as I need them for what I ask them to do.

Here's a great video from Paul Sellers on how he does it, most of my technique is inspired by him, except I am not good enough to do it completely free handed.

And here's another video from one of my favorite recently new youtube woodworking channels by Matthew Cremona.

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