Mortising chisel sharpening

Re: Mortising chisel sharpening

Tom Wolf

>I've always sharpened mortise chisels with only one bevel and that set at around 35 degrees. It seems to give the edge more strength and durability under high demand chopping.

Depends on lot of things

Dennis

>Would suggest you read Leonard Lee Sharpening book and then do a search here on the subject.

The use of a mortice chisel depends on what wood and if you pound or pare with it.

I find that 30deg bevel with the rounded edge works for most things i do but as we say YMMV

Dennis

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Re: Mortising chisel sharpening

Jim in Burlington Ontario

>Mine arrived late today and I'm just in the process of flattening the backs. I'm going to microbevel the last 1/8" with a 1 to 2 degree micro bevel to 4000. I had a look at Rob Cosman's and he had his hollow ground with a small micro bevel on them.

Re: Mortising chisel sharpening

Jonathan Peck - N.Y.

>I find sharpening without a hollow grind a bear because the mortise chisel is so thick that the bevel is longer than on a standard bench chisel. If you don't hollow grind, you'll have to remove alot of material to get a bur (not a Scott Burr) You can also throw me into the 35 deg bevel w/o micro bevel camp.

So how do you get LN mortise chisels and what sizes are available?

Regards

Jonathan

30 degrees approx grind, 32 degrees hone

Andrew F in Australia

>give or take.

I'd start out about there (I say about because I've never measured a bevel in my life - grind and hone freehand)

If you find that the chisel edge chips or folds over, regrind & rehone at a steeper angle until it works as intended.

Just my experience - yours may vary.

Cheers,

Andrew

Flattening LN?

Brad in Ottawa

>I sort of thought that you wouldn't have to flatten the LN chisels!?! Did I read right?

Brad

depends on the steel

bill tindall

>The more acute the bevel angle the better the penetration while choping and better penetration results in faster mortise making. So, it is desirable to grind the bevel to as sharp an angle as the metal will allow.

If the bevel angle is too small the edge will crumble or chip. The angle at which this problem will occur will depend on the toughness and hardnes of the metal. In addition, if the angle is too small and the metal not tough enough, then the tip will snap off while prying out chips. I expect these chisels will hold up at a bevel angle of around 30 degrees +/- a few degrees as A2 is a good steel and I am sure the LN has it hardened optimumly.

If the metal is tough enough then hollow grinding will not weaken the tip too much and result in tip breaking off when prying. A small secondary bevel will strengthen the tip and not affect penetration much.

Re: Flattening LN?

Tony - Memphis

>I have a set of their bench chisels and I didn't need to flatten them. I polished up the backs and that was it.

Tony

Re: Mortising chisel sharpening

Glenn Madsen

>"So how do you get LN mortise chisels and what sizes are available?"

In my case, you ask the nice lady at the LN booth at a trade show, and then get out your wallet. The chisel arrived UPS about three weeks sooner than she estimated.

I bought a 5/16" chisel. 3/8 and 1/2 were also available, but beyond that, I don't recall. Mine's still in the wrapper, having just arrived Tuesday.

These are called 'pre-production', although that seems to be more an operational category than anything else. The same tooling and facilities are used to make the bench chisels, and it's a balancing thing.

LOL ;-)

Scott Burr in Ben Lomond CA

>

Re: Mortising chisel sharpening

Jonathan Peck - N.Y.

>As a point of reference...I tried sharpening one mortise chisel with a hollow grind and one with a secondary bevel to see which I liked better.

As far as sharpening goes - the chisel with the hollow grind is easier to sharpen freehand as there is more surface area registering and it is easier to maintain a constant bevel angle while honing. With the secondary bevel method, I need to use a jig. I can't report any noticable difference in use.

Re: Mortising chisel sharpening

Wiley Horne--Glendora CA

>Rob,

I just got through chopping a bunch of mortises with a 6mm Japanese blue steel (a tungsten steel) chisel. This chisel is hollow ground, with a 25 degree overall bevel, and probably about a 27 degree hone on the tip--it's freehanded, but that's about right.

My experience agrees with Bill T., which is that a more acute bevel does a lot for you, provided the steel will take it. What I like to do is use the first two strikes to cut the biggest and deepest V-shaped plug I can out of the middle of the mortise. Cutting a big plug out of the middle of the mortise removes the lateral support from the wood on either side, so the remaining wood comes out 1, 2, nothing. In other words, the work goes really fast down to the depth set by your first strikes. So there's advantage is being able to drive the chisel deep, and I have noticed a big difference between a hollow ground blade in the high 20's versus previous experience with a straight bevel in the middle 30's. I should mention in the same breath that it's pretty easy to blue a chisel hollow grinding.

That's just my experience for what it's worth. You have new chisels. I'd use them just as they come from LN, and don't make any big changes right away. Later on, after some experience, drop Rob Cosman a line at his email and talk things over with him--he'll get back to you right away IME.

Wiley