Chisels go blunt quickly cutting housing dado
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Hi all,
I am a newbie at woodworking and, in preparation for the tote project, have started to practice housing dados on some scrap wood.
My chisels are sharpened using the method demonstrated by mr. Sellers and they come out really sharp. Maybe not quite as sharp as in the sharpening video, but close.
The problem is that they go blunt very quickly. I especially notice this when I offer my chisels up to the knife wall and strike down using my hammer. Even after 3 (gentle) strikes it doesn’t go in very far and I need 5 to 6 passes before I have cut away enough material.
Could it be a chisel problem? Some I bought new (cheap, unknown brand) but I also got an old Nooitgedacht one from my dad. They are supposed to be good, right?
Any ideas?
Regards,
Wesleybefore we can help we need to know some things, like:
1) how can you tell your chisels are dull–looking at them with a loupe? shaving end grain from a piece of pine?
2) what kind of wood are you practicing on? Hard wood behaves differently than soft. remember what Paul says repeatedly about the sound when you strike the chisel?
4) how do you know your chisels are sharp to begin with?notice #3 was missing? good. Stop. think. stop again. You can figure this out. Go back, and review your data, especially your sharpening videos. Think some more.
This stuff is not easy, (even though Paul makes it look easy) but you can do it.let us know how you do,
jim
Wesley, I’ve found brand new chisels tend to lose their edge quickly until you get down to good steel. I remember reading about this somewhere and the metallurgist stating something to the effect that the temper/hardening will be different at the very edge. Basically what this means is that you would have to sharpen more often on new chisels until you get beyond this edge. I did notice this on a set of chisels I purchased.
Next questions is what angle are you honing the edges of your chisels. I have heard 30 degrees for hardwoods and 25 for softwoods. 20 degrees for paring chisels not intended to be used for chopping only paring.
Last question is what kind of wood are you building the tote out of?
I had the same problem… The angle was too shallow (I calculate less than 25°) and the edge cracked and was lost fast, in pine I should add. I change it to a higher angle and then everything went smooth. Cannot help you with the exact angles cause everything is in my hand memory… that is the great thing of hand sharpening you modify your angles in the go…. so I guess this problem will help you a lot to develope the feel sharpening any chisels… look at it as the cheapest training you will have…
Hmm. Looks like it’s time to take a few steps back.
I assumed the chisels were sharp because I can cut through a piece of paper very easily. Again, not as well as seen in the video, but quite close. I’m using 220, 320, 800, 1200, 1500, 2000, 2500 abrasive paper + a leather strop for the sharpening. Couldn’t tell you which angle I — I’ll try with a 25 degree angle tonight using my honing guide.
When I’m about halfway cutting 1 side of the housing dado I can already notice my chisel performance has degraded. When I try it again on a piece of paper it hardly cuts anymore. Perhaps this is not the most scientific method.
The wood is pine, by the way. I don’t dare work on anything else until I’ve improved a bit more.
So I’ll resharpen again tonight using the honing guide. Going for a 25 degree angle this time.
Oh, and what sound is the chisel supposed to make in pine? I’ve seen lots of videos but I don’t remember Paul talking about this. I’m doing this on a B&D workmate and it makes an awful racket.
Thanks!
Wesley
Ok. Results have improved. Hete’s what I did different:
– Set my honing guide to 25 degrees.
– Gave it a back bevel (2 stops using the Veritas honing guide)
– Only ‘sanded’ the chisel in 1 direction
– Put the wood on a thick granite tile when cutting the vertical wall of the housing dado, rather than doing it straight on the workmate.The chisel seemed sharper, but that could also be my imagination. Using the granite tile also helped. I think the not-so-massive workmate was deflecting the force of the hammer.
All in all it took 3 passes to cut the housing dado. I notice I am getting better at them as well. It came out a bit too tight, but some light planing on the other board easily fixed that.
Wesley.
6 March 2014 at 1:03 pm #28631Wesley, The only thing I would change is eliminate the back bevel. You don’t want a secondary bevel on a chisel. You want the back dead flat so there is no deflection when cutting down to get a flat wall…
Brett-
Wesley may have meant a micro-bevel, not a “back-bevel”.
Wesley-
Paul’s method includes just a few grits, a strop, and no honing guide. The simplicity of his method makes me not fear or abhor sharpening any more. Paul suggests the use of a training block (of wood) to become familiar with the proper sharpening angle, but ultimately sharpening free-hand is what makes Paul’s method fast and fuss-free (especially with diamond plates).
I would aim for 25-35 degrees, depending on the type of steel and the type of operation. A2 steel should be 30+ degrees, while O2 can be 25-30. With Paul’s freehand method, the effective bevel angle is the angle at the very cutting edge, not the average angle of the convex bevel.
Do your Nooitgedacht chisels say what kind of steel they are? I have seen 1980’s Nooitgedacht chisels on my ventures, but I believe they were Chromium-Vanadium alloy, like most modern German chisels. I have also read of other people claiming Swedish steel on their Nooitgedacht chisels, as well as some others complaining that their Nooitgedacht chisels were soft. The quality may depend on what era the chisels came from.
Above all else when sharpening, I would make sure you create and feel for a slight, even burr all the way across your cutting edge, and train yourself to witness that wire edge coming off during the stropping process. Confirm by seeing if the edge reflects any light. Then you know your sharp without even testing.
Hope that helps.
Indeed, I meant to say micro bevel. The reason I use the honing guide is because I have only recently started and this gets me consistent results.
A set of diamond plates will be one of my next purchases. I think I have received the maximum achievable results using abrasive paper. They are sharp, but they can get sharper.
I only have 1 Nooitgedacht by the way. All markings are either gone or unreadable. Too bad.
Anyway. Thanks for your time and advice.
Wesley
7 March 2014 at 6:53 pm #28673Hi Wesley I think most of us has been there done that. I also worked on a Work Mate until I built my “Paul Sellers” style bench. The Work mate is a handy tool but for chopping not so much as it is light and bouncy. I sharpen all my chisel’s ( except Mortice Chisel’s which I use 35* ) between 25 – 30*, I sharpen Free Handed mostly and no back bevel.
I ordered ( 2 ) of the Eze – Lap diamond stones and hopefully will be here Today. My sharpening media is Sigma Power Water Stones up to 8000 grit and a leather strop. I have had great results but it does take some practice.
Steve
PS: I wanted to try Diamond Stones and also use them for when I travel so “no mess” to speak of.
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