Hope for a mortise chisel?

[Shawn Pixley]

I acquired a mortise chisel the other day. The price was right, free. The problem is, the blade is not square, it is a parallelogram. As a mortise chisel, that makes it an epic fail. So, my question. Is there any hope for this? I have thought of trying to file it square. I could take off the handle, heat it in the forge and pound it square. I think that I would likely screw it up. Any ideas to fix or repurpose?

I curse the maker of a parallelogram mortise chisel...

[Jack Curtis]

Drats, if only it were a trapezoid.

[Richard Shaefer]

is it a sash mortise chisel or a pigsticker mortise chisel?
I suppose it doesn't really matter.
grind that sucker back to square! (trapezoid ok, too, but only as long as the fat side is on the slick face!)

[daniel lane]

If it's fairly simple to grind one side to approach trapezoidal, I might spend the time to do that, otherwise I'd consider selling it on eBay as a one-of-a-kind piece, worth hundreds of dollars! ;) I would not grind the bottom to approach square, as the handle would be off and that will drive you crazy if you try to use it.

Seriously, if I couldn't fix it readily, I wouldn't waste the time trying - I get little enough time the in shop. Perhaps consider using it for sharpening practice, never with intent to use it in a mortise...


daniel

[Jim Koepke]

I curse the maker of a parallelogram mortise chisel...

Actually, this is a specialized mortise chisel for cutting a circular mortise in the hubs on wagon wheels.
At least that may be the story to bring in some big bucks on ebay. :D

jtk

[Chuck Nickerson]

Perhaps someone made it for sinking the mortises in wooden bodied planes with a skewed iron?

[Jessica Pierce-LaRose]

I missed this thread the first time round, but as I started reading it, my mind ran to exactly the same idea as Chuck did - it might be just the perfect thing for sinking a mortise for a skewed rabbet or something. I have no idea if it would work, that's was just the first thing that came to mind - it could be a terrible idea that wouldn't work in practice.

[Shawn Pixley]

Chisel is marked as Kangaroo brand. They were made by Sorby in my research. Here are a few poor pics.

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I think I'll try to file to a trapazoid unless I hear a better idea.

[John Coloccia]

I'm unclear as to what the problem is. What edges make the parallelogram? As long as the back is flat, the two edges adjacent to the back are parallel, and the two edges adjacent to the bevel are no further apart than the back edges (closer together is OK), it will make fine mortises. I do question, though, if that's actually designed as a mortise chisel. The handle wouldn't make a good striking handle, it doesn't seem thick enough, and it seems far too long. You'd expect a paring chisel to be thinner, but doesn't it seem closer to a paring chisel than a mortising chisel?

[Shawn Pixley]

John

Sorry I don't have a better picture. The cross section is a bit of a diamond shape. When you would cut down a mortise, with the sides registered against the sides the cutting edge would not be perpendicular to the mortise sides. It is off about 1/32" across the 1/4" width. It doesn't work as a mortise chisel and can't be used in tight places.

[Chris Vandiver]

Turn the shape into a trapezoid. Carefully grind the offending side. That brand chisel was/is considered pretty good. It's not unusual for a hand forged tool to be a little out of shape.

[Jim Koepke]

+1 on what John said about it not looking like a mortise chisel.

If it is not a mistake that slipped past quality control, it would be interesting to find out what kind of purpose it was made to serve.

jtk

[Chris Vandiver]

I'm unclear as to what the problem is. What edges make the parallelogram? As long as the back is flat, the two edges adjacent to the back are parallel, and the two edges adjacent to the bevel are no further apart than the back edges (closer together is OK), it will make fine mortises. I do question, though, if that's actually designed as a mortise chisel. The handle wouldn't make a good striking handle, it doesn't seem thick enough, and it seems far too long. You'd expect a paring chisel to be thinner, but doesn't it seem closer to a paring chisel than a mortising chisel?

The chisel in question is a "sash mortise" chisel.