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-   -   My new chisels don't hold an edge. (https://www.woodworkingtalk.com/f11/my-new-chisels-dont-hold-edge-30003/)

PaperJam 09-19-2011 09:41 AM

My new chisels don't hold an edge.
 
So I finally got my new chisels, got them all sharpened and went to work on learning to cut dovetails following a video from the Wood Whisperer.

I was frustrated to find that my chisels needed to be resharpened after finishing each dovetail, and sometimes even sooner than that. I was cutting half-blind dovetails in white oak to practice making drawers for a desk I'm building.

I found that most of the wear came (expectedly) from chopping across the grain to separated the chips.

My question: Did I buy an inferior chisel, or is this to be expected when using any chisel on white oak. Also, is there maybe something wrong with my technique to where I am hitting the chisels too hard maybe?

For now I'll keep my sharpening setup at hand while chisels are in use. The chisels I bought are these
http://www.woodcraft.com/Product/200...hisel-Set.aspx

Thanks for any info
-Jeff

cabinetman 09-19-2011 10:18 AM

While White Oak is hard, chisels shouldn't need sharpening that often. It might be that you feathered the angle too thin, as in changing the angle more acutely.








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woodnthings 09-19-2011 11:44 AM

your link to Woodcraft....
 
Has a Comment section down below the photos. Here's what one purchaser had to say:

Comments about WoodRiver 8 Piece Bench Chisel Set :
These chisels look beautiful with their Bubinga handles. If you buy this set, be prepared to spend a little bit of time flattening the back of each chisel. These chisels are intended for paring and very light chopping. I sharpen mine at a 25 degree angle on water stones. The edge does not last very long and you have to polish the secondary bevel quite often (the steel is not of the highest quality, apparently...) If you want to do more serious chopping, buy another set and grind the bevel at a 35 degree angle, or buy mortising chisels (usually quite a bit more expensive...) All in all, this is a decent set for a beginner to intermediate woodworker, and it will allow you to do good work, even though you will have to sharpen more often (that's a good way to learn!) Once you are more experienced, buy a better (and more expensive) set and keep this one as your knock around set.

So based on that, you might expect the same conditions.
The R or Rockwell, rating, which is used to measure the hardness of various metals is the key:
http://en.wikipedia.org/wiki/Rockwell_scale

The R rating was not listed for those chisels, that I could determine, but it's obviously on the "soft" side, possibly somewhere near the 55 value unfortunately.
Typical values

  • Very hard steel (e.g. a higher quality knife blade): HRC 55–66 ( Hardened High Speed Carbon and Tool Steels such as M2, W2, O1, and D2, as well as many of the newer powder metallurgy Stainless Steels such as S30V, 154CM, CPM-M4, ZDP-189 , etc. )[12]

You might consider returning them for a higher quality set if they are still in new condition or a very recent purchase.

Some of the highest quality chisels are made with laminated steel like these from Japan Woodworker, but they are pricey.
http://japanwoodworker.com/product.a...&dept_id=12763

There are others with good steel that won't require a government stimulus loan to purchase, but I can't not personally recommend any particular brand. Marples is one name and probably anything from Lee Valley or Sorby. ;) bill

Hammer1 09-19-2011 02:03 PM

2 Attachment(s)
Many chisels come with a 22-25 degree bevel. This is the primary bevel, you have to sharpen them at a secondary bevel, 30 for softwoods, 35 for hardwoods. This is true for the majority of chisels, Sorby's won't be any different than the Wood River chisels. The edge holding difference by sharpening to the proper bevel will amaze you. Same thing happened with me when I bought some new Sorby's. They are the ones that gave me the info.

woodnthings 09-19-2011 03:34 PM

Micro bevel
 
Quote:

Originally Posted by Hammer1 (Post 246762)
Many chisels come with a 22-25 degree bevel. This is the primary bevel, you have to sharpen them at a secondary bevel, 30 for softwoods, 35 for hardwoods. This is true for the majority of chisels, Sorby's won't be any different than the Wood River chisels. The edge holding difference by sharpening to the proper bevel will amaze you. Same thing happened with me when I bought some new Sorby's. They are the ones that gave me the info.

I do the same thing with jointer and planer knives:
http://www.antiquetools.com/sharp/sharpmicrobevel.html :thumbsup:
However, I do think the metal hardness, R value, plays a role in the longevity of the useful edge. I have everything from Companion (Sears Cheaper line then Craftsman), Craftsman, Stanley and the Japanese laminated steel and a few Buck Bros. You can always tell which ones are the hardest steel, they really hold their edge. ;) bill

cabinetman 09-19-2011 03:50 PM

The chisel may have never been 'tempered' correctly or could have lost its temper with certain sharpening methods. The steel can be hardened by 'quenching', and may hold its edge longer.








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Hammer1 09-19-2011 09:54 PM

You are right, Bill. There is a delicate balance between sharpening ability, hardness and brittleness. I have lots of chisels, too. I'm still searching for ones that will hold a 20-22 degree edge for fine paring work. Lie Nielsen is now making some that are harder in 01 steel. I don't think you want to do much hammering or prying with them, though. I wish they'd make them in a tang style, I don't like sockets.

http://www.lie-nielsen.com/catalog.php?sku=O-1-C

Leo G 09-19-2011 10:57 PM

Cheap steel is the likely culprit. Spend money on a good set. Marples is about as cheap as I would go. Anything that has Sheffield steel in it is good.

BigJim 09-20-2011 02:25 AM

Two Cherries makes some good chisels and here are some good looking German chisels
http://www.garrettwade.com/special-g...et/p/08C06.01/

Admiral 09-20-2011 08:39 PM

Two things.

First, these woodriver chisels haven't gotten the best of reviews. That being said, sometimes the edges don't properly take a temper, so the OP should grind back about 1/8" on each edge, resetting the bevels, and see if edge retention improves. This sometimes will work and you'll see the difference immediately, so try it on one chisel.

Second, price is generally reflective of quality. Sets of chisels are seductive, but buying two or three of your most used sizes from a true quality maker might be more cost effective for you.

YMMV......

johnray 09-22-2011 07:32 AM

Go the the fleemarket this weekend and buy some old Stanleys. Then throw the new ones away.


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