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Sharpening Pigsticker Mortise Chisels

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Forum topic by Greg In Maryland posted 03-03-2014 02:45 PM 831 views 0 times favorited 13 replies Add to Favorites Watch
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Greg In Maryland

413 posts in 1694 days


03-03-2014 02:45 PM

Topic tags/keywords: pigstickers sharpening zen perfection chisels

Hey all,

Nothing says ‘snow day’ like sharpening pigsticker mortise chisels. And bacon, but that is another topic.

I am rehabbing a mismatched set of mortice chisels and have a few questions about how far to sharpen the chisels.

I am putting a 20ish primary bevel with a 30-35ish secondary bevel. Of course I am flattening the backs. To accomplish this, I am using a Worksharp 3000 to get rid of most of the waste and establish the bevels, followed by Norton Waterstones for fine polishing.

So, should I fully sharpen/polish the primary bevel (ie., to mirror finish, able to cut hair, paper and air) and then go back to grind/polish the secondary bevel? Or can I stop mid way through the process of finishing the primary bevel and then move to the secondary bevel?

Regarding the sharpening end point, when do I stop? Do I treat the mortise chisels like my paring chisels and sharpen them to a zen like sharpness, or stop before total perfection is reached?

Thanks.

Greg


13 replies so far

View waho6o9's profile (online now)

waho6o9

5116 posts in 1273 days


#1 posted 03-03-2014 03:56 PM

Not too sure but I wouldn’t put a secondary bevel on a mortise chisel.

I’d put a wicked sharp edge on it for sure.

View brtech's profile

brtech

682 posts in 1618 days


#2 posted 03-03-2014 04:03 PM

I’m not an expert, at all, in sharpening, but it’s pretty obvious that you only need a really rough “edge” on the primary bevel. Whatever your coarsest grit is, that’s all you need. You want it straight and flat, and that’s it. Draw a picture and you will see that after you grind the primary bevel, you regrind the edge, a bit back from the point where the secondary bevel intersects the the back of the blade. Any effort you put into polishing the primary is ground away when you establish the secondary bevel.

I could imagine there is some point (grit level) that is too coarse, but we usually start with something above 50 or s grit, and I think the math works out that the edge created by that grit is completely wiped out by the initial secondary bevel grind.

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jmos

681 posts in 1065 days


#3 posted 03-03-2014 08:43 PM

Right or wrong, I sharpen mine like I do my bench chisels. Once the back is flat and polished (1000grit, 4000grit, 8000grit); sharpen the primary on a 1000grit stone until the edge is straight and I raise a burr all the way across. Flip and remove the burr with the 8000grit stone.

Then switch to the secondary bevel angle and sharpen that for a few passes at 1000 grit to raise a burr. Then tip up just a bit more to make a micro-bevel and take a couple of strokes on a 8000grit stone. Flip and remove the burr on the 8000grit stone.

When it dulls I go back to the secondary bevel angle and the 1000 grit stone until I raise a burr. Then tip up to the micro-bevel and a couple of swipes on the 8000grit stone, remove the burr on the 8000grit stone. I can do this 3-5 times before it takes too long to raise a burr on the secondary bevel I go back to the primary and regrind.

20ish sounds a little low for a mortise chisel; the edge may be too thin and chip. Lie-Nielsen’s come at 25. If you have any issues, just regrind the primary a bit higher so there is more meat at the tip to resist the pounding and prying.

-- John

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titanxt

30 posts in 427 days


#4 posted 03-06-2014 04:23 PM

I have a couple of the Ray Isles mortising chisels. They come with a secondary bevel from the manufacturer. Saves time and easier to touch-up for sure. I go with a rough primary bevel (not polished) and hone a secondary bevel. I only touch up the primary bevel when I think the secondary bevel is growing too large and therefore taking too much effort to sharpen.

Andy

-- www.creeativewoodworking.com

View bigblockyeti's profile

bigblockyeti

1670 posts in 417 days


#5 posted 03-06-2014 04:42 PM

Andy, do you put a micro bevel at the edge of the secondary bevel or just sharpen and polish the entire secondary bevel?

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titanxt

30 posts in 427 days


#6 posted 03-06-2014 04:59 PM

I just continue to do what the manufacturer did, and that is to sharpen and polish the secondary bevel only.

Andy

-- www.creeativewoodworking.com

View JayT's profile

JayT

2437 posts in 907 days


#7 posted 03-06-2014 05:07 PM

I’m definitely no expert, but you might read this page from Tools for Working Wood about mortising chisels. The fourth paragraph talks about the angles and why. Made sense to me

Edited to add link

-- "The American Republic will endure until the day Congress discovers that it can bribe the public with the public's money." Alexis de Tocqueville, 1835

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titanxt

30 posts in 427 days


#8 posted 03-06-2014 05:10 PM

Jay hit the nail on the head as to where I received that information. I bought my chisels from Tools for Working Wood and followed their instructions.

Andy

-- www.creeativewoodworking.com

View Greg In Maryland's profile

Greg In Maryland

413 posts in 1694 days


#9 posted 03-06-2014 06:56 PM

Thanks for all the responses. Very helpful as always.

One follow on question, the Tools for Working Wood link on Mortice Chisels is specifically written about Ray Isles mortising chisels, which are constructed of D2 steel.

would there be a concern using the same approach (20 degree primary bevel with a 35 degree secondary bevel) on vintage chisels (and steel)?

Thanks.

Greg

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titanxt

30 posts in 427 days


#10 posted 03-06-2014 08:50 PM

How are the chisels now?

Andy

-- www.creeativewoodworking.com

View JayT's profile

JayT

2437 posts in 907 days


#11 posted 03-06-2014 09:25 PM

I don’t know why there would be any different approach, regardless of the steel. Any material used in a mortising chisel needs to have that strength and the usage is the same.

The only real difference in material might be how long it keeps an edge.

-- "The American Republic will endure until the day Congress discovers that it can bribe the public with the public's money." Alexis de Tocqueville, 1835

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Greg In Maryland

413 posts in 1694 days


#12 posted 03-07-2014 03:51 AM

Hey andy,

I know very little about them other than the sizes and makers mark:

Sorby
Brooks & Sons
W. Butcher
W. Marples & Sons
W. Phillips

It is a mismatched set for sure.

I would guess that they are late 1,800’s to early 1,900’s.

I am going to grind them 20/35 degrees and see what happens. Worse comes to worse, I can always regrind.

Greg

Greg

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mafe

9573 posts in 1785 days


#13 posted 03-09-2014 08:27 PM

You can try and take a look here:
http://lumberjocks.com/mafe/blog/23179
Best thoughts,
Mads

-- Mad F, the fanatical rhykenologist and vintage architect. Democraticwoodworking.

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