Mortise Chisel Question

[John Dingman]

I am working on a project for the LOML. :)
http://www.newyankee.com/sketches/713s.gif
A Chimney cupboard made out of antique pine. I am going to need to chop some mortises in the door frame as the design I am going to use has through mortise and tenon joinery. Are These (http://www.leevalley.com/wood/page.asp?page=49988&category=1,41504,41533&abspage=1&ccurrency=2&SID=) good for the money or would you recommend something else?

http://www.leevalley.com/images/item/woodworking/chisels/55j0506s1.jpg
Thanks for your help,
John

[Mark Kelly]

I have the 10mm (3/8") chisel you posted above. I have recently done a lot of chopping with it. It is a heafty beast of a chisel, but that is what it is supposed to be. However, and this may be because of my technique or I let it get too dull before sharpening, I did notice that at times it gets some VERY minor chipout at the cutting edge. I used it mainly in red oak and a lot in western maple. However, since I haven't been able to compare it to any other mortise chisel, I also don't know if this is what normally happens.

All in all, I like the chisel a lot, and once you get the hang of it, chopping mortises is pretty easy and quick.

[Tom LaRussa]

I am working on a project for the LOML. :)

A Chimney cupboard made out of antique pine. I am going to need to chop some mortises in the door frame as the design I am going to use has through mortise and tenon joinery. Are These (http://www.leevalley.com/wood/page.asp?page=49988&category=1,41504,41533&abspage=1&ccurrency=2&SID=) good for the money or would you recommend something else?

John,

I don't know about those particular chisels, but I've never been unhappy with anything I bought from Lee Valley so I expect they are at least a decent value. They certainly look hefty enough, and the construction looks pretty darn solid between the 1/2" thick blades, the hornbeam handles, the hoops, and the leather thingie. I'd say you could probably whale away on them until doomsday without doing them much harm. This is all JMHO though, based on a picture and what little I know about tools.

One cautionary question though. Have you ever cut mortises in pine? I did for my hacker bench and it was not a fun experience. Admittedly I was working with cruddy tools, but that stuff splintered like you would not believe. Pretty near impossible to contain the edges of things.

OTOH you are not using freshly cut, construction grade lumber from the BORG, so things will probably be different.

[Pam Niedermayer]

I haven't used 2 Cherries mortising chisels; but I have used similar chisels from Jim Wilson/Steve Knight. There is no finese there, the blade style being straight rectangles, they seem big and brutish. When I tried them on pine (not antique) it was a disaster, splitting all over the place; so I went back to using Japanese and old western style mortisers, which have front sections very slightly narrower than the back sections which seems to help make clean cuts without splits. I've still got a couple of the Wilson chisels to try on huge pieces some day, like logs.

Pam

[Mark Singer]

I tend to agree with Pam...the angle is too steep for pine

[Bob Smalser]

Surface splitting depends on the grain of the wood and its density...some softwoods like spruce are simply crisper than others, and vertical grain stock generally works cleaner than flat grain. The drier the wood the more prone to splitting, too.

Scribing your layout lines deeply helps. If you believe the top edges of your rectangular mortise chisels need relieving, it would be a simple matter to grind a bevel there.

Otherwise if it takes drilling and paring to make an acceptable mortise in that particular wood, then drill and pare.

http://www.sawmillcreek.org/showthread.php?t=13246&highlight=haunched

http://pic3.picturetrail.com/VOL12/1104763/5536778/70922021.jpg

[John Dingman]

Bob,

Thanks for the link to the tutorial, it was very helpful!

John

[Pam Niedermayer]

So, Bob, are you saying that you think it doesn't matter what style chisel you're using on what wood and size of wood?

Pam

[Mark Singer]

Pam,

I think the angle of the grind is one of the factors. Mortise being a less steep....could tend to wedge and split

[Bob Smalser]

So, Bob, are you saying that you think it doesn't matter what style chisel you're using on what wood and size of wood?

Pam

Not necessarily....just saying there is a heck of a lot more involved and more important (grain, SG, EMC) than the bevel angle....and I'd probably be drilling and paring long before I reground my valuable chisels over a cheap hunk of pine unless I worked with pine exclusively.

Splitting is also relative....if the tenon hides it, it's inconsequential.

I don't mortise much of my Western White Pine, but I do mortise a lot of my Doug Fir, which is a bit denser, and splitting isn't a big problem, although lack of crispness (below - furry surfaces) is an irritant compared to hardwoods. My Western Red Cedar and Sitka Spruce, in contrast are very crisp and cut cleanly:

http://pic3.picturetrail.com/VOL12/1104763/3442941/42268168.jpg

[Pam Niedermayer]

I wasn't talking about the chisels' bevel angle, only about the overall shape of the chisel and how that contributed to the chop. For example, in my case the pine split when using square mortising chisels and it did not split when using Japanese chisels with trapezoid shapes. And even in the 2 or 3 mortises I managed to cut with square chisels without splitting, the resulting mortises were messier, more ragged, than the mortises cut with Japanese chisels.

BTW, there are plenty of older western chisels with trapezoid shapes.

Pam

[Bob Smalser]

I wasn't talking about the chisels' bevel angle, only about the overall shape of the chisel and how that contributed to the chop. For example, in my case the pine split when using square mortising chisels and it did not split when using Japanese chisels with trapezoid shapes. And even in the 2 or 3 mortises I managed to cut with square chisels without splitting, the resulting mortises were messier, more ragged, than the mortises cut with Japanese chisels.

BTW, there are plenty of older western chisels with trapezoid shapes.

Pam

I agree....guess I was muddy: "If you believe the top edges of your rectangular mortise chisels need relieving, it would be a simple matter to grind a bevel there."

It doesn't take much relieving on the grinder to make a slight trapezoid.

I have and use both and haven't noticed much of a problem, but wouldn't hesitate to modify the tool for the task.

Another aspect of this that might help but hasn't been discussed is to hone the sides of the cutting edge bevel as well as the cutting edge. True, it's a 90-degree bevel, but I've worked with folks who swore by it when our finicky mortising machine went out of whack way back when. Dunno if it was the cleaner corner or the honing adding a slight trapezoid to the blade profile, but it might be worth a try.