Re: sharpening a corner chisel

[bighillman]

Hello. I've got a Robert Sorby framing corner chisel and I'd like to sharpen it on my Tormek T-7. Does anyone know how? There are some videos on youtube using other methods than a grinder but very involved. Perhaps there's a jig one can make. I've tried doing it freehand but made a bit of a pig's ear of it.

 

[zb1]

Can't offer any advice on using a Tormek but I just sharpen mine with a normal diamond stone. With the chisel held at an angle to the stone you can get in quite close to the tip. I then finish the very corner with a fine triangular needle file then take the burr off as with a normal chisel. If you contact Sorbey they will probably regrind it for you to a desired angle, for a fee probably.

Zach

 

[Argus]

.

Corner chisels are tricky. (These are otherwise known as a Bruzz).

Because you are honing the two outside faces (at right angles) dead flat you must not have any bevel at all, otherwise it will not cut accurately into a corner and force the chisel outwards..

The inside edges are opposed right angles and the honing angle is of your choice – let’s say 30 degrees and also need to ne honed dead flat on each plane. This means that you will end up with a ‘hook’ at the corner where the two angles meet. Unless you get rid of this hook, the chisel will not cut properly and will leave an uncut bit of wood in the corner.
The same problem exists on carvers’ Vee chisels, but, because the bevel is on the outside and the edge is rounded, the hook problem is overcome by honing the outside edge angle in a rocking motion. Text books on carving, Chris Pye’s in particular, will explain this.

On a carpenter’s corner chisel you must get rid of the hook (or tolerate raggy corners) by honing at an exact angle on the inside right into the corner.

Probably the most tricky and exacting bit of honing there is.

Sorry about this, but I can't see any way that you will put a decent and exact cutting edge on an inside edge at right angles with any form of electric grinder. But if it's only for roughing out the insides of mortises, then you will probably be able to put up with a raggy cut in the corner. But, whatever you do, don't bevel the outsides.

Best regards

 

[bighillman]

Thanks a lot. I do use it for mortices and I've managed to put good edges on so it's OK for that. I'll try the suggested method of Zach's too.

 

[Benchwayze]

I often considered using one of these, but then I thought about the sharpening. I decided it was just as easy (and cheaper) to square off a mortice or rebate corners with an ordinary chisel. (If I have to that is.) I did put an old hollow chisel aside, and kept that square. Just turned up a small handle to slide over the shank, and 'Robert's your Father's brother'. it fell down behind the work-bench though, and there's spiders and mouseies down there! :mrgreen:

 

[jimi43]

I just used my bootfair bruzz for the first time this weekend to cut some mortises in green chestnut...

...and BTW...it now has a handle.....

And I just flattened the backs using a coarse then fine natural hone...which left a very fine wire edge on the inner bevels.

I then just stroked these off with a fine DMT mini diamond hone. The thing is razor sharp and cut through the wet wood like a knife through butter. If you're not confident at all with the inner bevel grinding...leave them and just do this with the wire edge. It's more than enough to get a fine edge.

Jim