Jointer knives

[Dunne E. Dawe]

I've just downloaded the user manual for the Powermatic 8" jointer. Much better value than the inscrutable Taiwanese manual that came with my 8" copy of this fine machine. I read with interest the sharpening technique in this manual and they said to use a hard Arkansas stone. I can't find such a stone at my local woodie shop, and wondered if it went by another name. I then wondered if the "scary sharp" technique could be used for this purpose. The wet-n-dry could be left off the glass that rubbed on the table, and the blades would be the only things that cop a sharpen. If this is a viable way, what grit would folks use to touch up the blades every week of use, or so?

[Bill Schnakenberg]

You might try a sporting goods shop. KA-BAR supplies both soft and hard arkansas stones for knife sharpening. I was given a KA-BAR kit that contains both stones and honing oil. I don't know how old this kit is, but the instructions say 'Rev. 79'. I checked at the KA-BAR site and don't see the kit there, but they do sell the stones separately. You can check for local dealers by inserting a zip code or go to a catalog site. See the stones under 'Products' - 'Accessories', and the dealers/catalog under 'Where to Buy'.

[Bay Area Dave]

go to a hardware store and get a 6" stone; it doesn't HAVE to be specifically an Arkansas stone. I use a double sided oil stone on my Powermatic. nothing expensive or exotic. It works great if for no other reason that it makes the blades totally parallel to the tables even if you didn't lock them into the head absolutely straight (course you have to get it within a few thousandths; you won't be taking much off with the stone).

dave

Dunne E. Dawe wrote:

[Dunne E. Dawe]

On Thu, 03 Jun 2004 13:43:30 GMT, Bill Schnakenberg posted:

I tried some of the links but could not get the products one to work. Anyways, I'm in Australia and it looks like stones big and flat to sharpen jointer knives are quite expensive, so unless someone gives me a good reason not to try the scary sharp method, I will give that a try. I think I've got a bunch of 1200 grit wet-and-dry which I hope will be suitable.

[Dunne E. Dawe]

On Thu, 03 Jun 2004 13:59:55 GMT, Bay Area Dave posted:

Thanks Dave I always thought this method reduced the clearance behind the edge, but I suppose this doesn't matter much if you are only taking off a tiny amount to restore the edge. Eventually I guess you are going to have to restore the proper bevel. I wonder what the symptoms are when you have insufficient clearance and need a regrind.

[Bay Area Dave]

Most likely a big nick will be the determinining factor in having to regrind rather than hone. As you said, the honing should be removing only a TINY bit of the edge.

dave

Dunne E. Dawe wrote:

[bridger]

if you are thinking of using scary sharp to hone the blades out of the jointer, yes, absolutely. it works great, as long as your jig prevents the blade from flexing.

if you are considering it for the bit of applying an abrasive to the blades while the cutterhead is spinning (which is what it looks like from your OP) I'd think it wouldn't work too well. the paper would likely tear and the possibility of glass breakage is too great.

if you are thinking of a honing jig that touches up each blade one at a time, it should be doable- but I think I'd try to get a granite countertop cutoff instead of glass.

[bridger]

it stops cutting.

[JMartin957]

I've never seen a jointed knife stop cutting, but they do get loud and you can feel them banging into the work.

John Martin

[Dennis W. Ewing Sr.]

I prefer to send them to a commercial sharpening service. I own a printing company and the knifes we use to cut paper have to be sharp enough to shave with. I can get eh same edge by sending my planer and jointer knifes to them. Call and ask if they sharpen paper cutter knifes. then ask is they can put the same edge on your wood working knifes. Keep 2 sets, one to have out being sharpened and one in the machine. I spend enough time sharpening chisels and gouges. I need more time to make shavings. This is the way.

[CW]

Yes, it eliminates the back clearance. The only time I would use the technique is when the knives are initially set. It would ensure that they are all at exactly the same height. The small land that this would generate would not be noticeable performance wise but I wouldn't do it on a regular basis, it would just accelerate the need for sharpening. Zero clearance will make it act like a dull cutter.