Thread: A "Blunt" chisel..
13th February 2014, 09:42 PM #1
A "Blunt" chisel..
Quite a while ago, I came across Bill Carter & his "blunt chisels". I think they'd be better called "extra-high-bevel-angle chisels", but "blunt" conveys the idea, I suppose. What they are really, are simply sharp chisels with an extremely high sharpening bevel - a tad less than 90 degrees, or you can make them a full 90 degrees if you like. This means that what you have is essentially a scraper disguised as a chisel.
I first tried the idea out using a 3/8" turning scraper, which was ground to a 'fingernail' shape. Sometimes the fingernail shape is handy, but sometimes I need sharp corners, so recently, I decided to make myself a dedicated 'blunt chisel' from a piece of 3/8 x 3/8" HSS. I didn't really need to, but gave it a bit of shape, the idea being both to make it look a bit more interesting & reduce the thickness that needs re-grinding each time that becomes necessary. After wearing away half a grey grindstone, and fitting a handle, this is what I ended up with:
The business end is ground at about 85 degrees or so: Blunt end.jpg
So, what's the point? The answer is that it's the bees' knees for paring fractions of millimetres from end grain, or near end-grain such as the bed of a wooden plane when you are going for that last bit of perfection in flatness. You can remove super-fine shavings off the end grain of hard woods very controllably:
And because you are taking such fine shavings, you can pare right over an edge, with little risk of splitting it away. This block of Flame She-oak has had numerous passes over the left edge, without a single splinter coming away:Pared edge.jpg
This sort of tool is really handy when paring the edges of the mortise in a marking gauge, for example. I like to cut the mortise about 0.5mm under size, then file & pare it (with a coarse file made 'safe' by grinding the teeth off the sides) to get a dead-square mortise that firmly fits the beam:
Cocobolo small g.jpg
My new chisel works better than my old turning scraper, partly due to the straight edge & partly because it's shorter & more controllable....
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31st March 2014, 02:29 PM #2
Instead of wearing away your grinding wheel, perhaps you could have reduced most of the thickness with one of your thin cutting discs in the angle grinder. The you could have resorted to the bench grinder or is this the benefit of hindsight?
In any event the chisel looks really neat (as usual .)
"Power tends to corrupt. Absolute power corrupts, absolutely!"
31st March 2014, 07:39 PM #3
1st April 2014, 04:05 PM #4
23rd June 2014, 02:50 PM #5
Very nice chisel Ian.
I've been wanting one of these for about 3 years.
Thanks for the inspiration and the only description of how it works and how to sharpen it I could get my head around. A sharp,blunt chisel is a confusing concept.
Here's my attempt.
A rusty 3/4 inch Aussie made Stanley chisel I got as a "postage enhancer" with a couple of Ward socket chisels off ebay.1st pic is before,It's the one with the beautiful yellow handle.
It took an afternoon to lap the pitting off and true up the out of square edge.
The handle is a branch off my neighbors macadamia but tree and the beat up ferrule is off a flea market buy.
It came out all right considering it's made from 100% garbage.
Best of all it works.
29th January 2015, 12:49 AM #6GOLD MEMBER
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- Mar 2010
I can't remember carter's discussion exactly (I bought the picture CD some of you others may have bought when it was available), but have used that type of scraper quite a bit.
I made mine out of a socket chisel and put a long handle on it so that I can put the plane in the vise and really go at it with the scraper. I believe bill may have said something about hardening and then not tempering (which is what I did).
I don't have a picture of mine, but do have it in video (18:40 in this video).
Great tool to have for spot removal, especially when the wood gets on the hard or abrasive side. I never sharpen it with anything more than a 400 grit diamond plate. As long as the edge isn't worn, it works great.
I like it with a little bit of camber on it.
29th January 2015, 04:50 AM #7
My Friend George showed me his. He bought a cheap set of 6 Chisels & just Squared the ends, with a very very slight angle, & man, do they work beautifully, just like those in the Photo, doing end grain.
I have a small problem, I also bought 6 Chisels from our local Sunday Market, @ $3 ea. but I put them somewhere in the Shed, but I can't find them.
Oh Dear, to be getting older.Regards,
Have Lathe, Wood Travel.
30th January 2015, 07:09 AM #8
I think concepts great simply because through a handle you can apply a lot of pressure on a small area to scrape. Which means you don't need a perfectly turned hook on the edge to get results. Cant really apply as much pressure with a card scraper.
just an opinion. not an expert on anything. 2 cents worth.
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