jointer blades - how sharp is sharp?

[Jesse Tutterrow]

It was (past) time to replace the 6" jointer blades on my Delta. So, after checking with here, I purchased a set from Global Tooling. They arrived last night (UPS delivered them about 6:30pm).

Opened the package this morning. No burr, but I was supprised that they did not feel very sharp. So I tried the paper sharpness test. I took a (used) piece of computer paper and tried to use the knife to cut the edge. I would barely cut! The paper was more willing to bend than be cut by the knife.

So, How sharp should the Jointer Knife be?
Am I expected to sharpen the knives I just bought?

Thanks in Advnace,

Jesse Tutterrow

[glenn bradley]

I don't run a knifed jointer anymore but when I did, the knives were like a razor blade. One casual mis-handle and you were bleeding.

[Brendan Plavis]

I always learned the shaving technique, to test a knife's sharpness..

I generally Ill try to shave either a knuckle, or a spot on my arm, to see if its sharp(I have a couple jack knives that I am constantly sharpening for work(opening up boxes upon boxes...)

They always told us in Boy Scouts to rub your finger across the blade, but, I found rubbing it along works just as well(you get a small nick if its sharp...) But I dont recommend this...


I would try to fire it up in the jointer to see if it works... thats a sure fire way...

[Dan Friedrichs]

I'd be interested in the replies to this, too. I did basically exactly what you did (bought a set of knives from Global tooling, tried to cut paper, didn't work, posted here. Here's my old thread: http://www.sawmillcreek.org/showthread.php?t=106475)

At the time, I accepted the wisdom of the Creek and used them as-is, but I'm beginning to think they could be much sharper. I used a different jointer that had razor-sharp knives in it, and it was much easier to use, and the edge did not immediately dull like some suggested would happen.

I'm planning to take mine out and send them out for sharpening...

[Pat Germain]

I've never tried the paper cutting test with my jointer knives. But when I first got my 8" Shop Fox jointer, the blades were very sharp. I accidentally cut myself putting it together. (Ouch!). And I just barely touched the blade.

When I had the blades sharpended a few months ago, they came back even more sharp than from the factory. (I swear, my sharpener can create a one-molecule edge!)

[Dan Friedrichs]

I've never tried the paper cutting test with my jointer knives. But when I first got my 8" Shop Fox jointer, the blades were very sharp. I accidentally cut myself putting it together. (Ouch!). And I just barely touched the blade.

When I had the blades sharpended a few months ago, they came back even more sharp than from the factory. (I swear, my sharpener can create a one-molecule edge!)

That's how I thought they were supposed to be. With the ones I got from Global, I think I could squeeze the blade as hard as I could in my hand and not cut myself.

[Pat Germain]

That's how I thought they were supposed to be. With the ones I got from Global, I think I could squeeze the blade as hard as I could in my hand and not cut myself.

Sounds like those would need sharpening. I'm no expert, but in my experience, sharp jointer blades work much better than dull blades. It's like shaving. Find a good sharpener and treat him well. (I think that's good advice for any woodworker.)

EDIT: Oh, dude! I just noticed you're in Colorado. If you're anywhere near Colorado Springs, I highly recommend taking your jointer blades, and anything else requiring an edge (to include kitchen knives) to Rick at Rick's Edge. He's in the phone book and has a little, privately owned shop.

[Brendan Plavis]

That's how I thought they were supposed to be. With the ones I got from Global, I think I could squeeze the blade as hard as I could in my hand and not cut myself.

You can also squeeze a razor all you want, and not get cut... Inorder to be cut by something sharp, you friction must occur, such as rubbing your finger over the blade...

Ever see sword walkers? Its not that their feet are of iron, but rather they dont let themselves move, so they dont get cut....

[John M Wilson]

You can also squeeze a razor all you want, and not get cut...

Have you ever actually tried this? Well DON'T! A very sharp knife (like a razor) will cut through material without any lateral motion at all. The "sawing" motion uses imperfections along the blade face to make a cut with less resistance, but a sharp enough blade will cut human flesh very easily with no sawing motion whatsoever.

Remember, Safety First!!!!

[Jeff Willard]

You can also squeeze a razor all you want, and not get cut... Inorder to be cut by something sharp, you friction must occur, such as rubbing your finger over the blade...

Ever see sword walkers? Its not that their feet are of iron, but rather they dont let themselves move, so they dont get cut....

Don't try this at home. I've been cutting meat for 30+ yrs., and the first thing I heard as an apprentice was, "knife pressure, don't saw the meat". If anybody needs this confirmed, I will gladly demonstrate.

[James Williams 007]

I have ordered jointer and planer knives from global and they are always sharp and ready to use. Now they are not as sharp as my chisels and plane blades but I spend some time doing those myself and I could shave with them.

[Nathan Palenski]

You can also squeeze a razor all you want, and not get cut... Inorder to be cut by something sharp, you friction must occur, such as rubbing your finger over the blade...

Ever see sword walkers? Its not that their feet are of iron, but rather they dont let themselves move, so they dont get cut....

Not all edges are the same. Frequently laminated blades require you to slice but its not the rule.

A meat cleaver wouldn't work if blades only worked by slicing.

[Brendan Plavis]

I could be wrong, but I think those create the friction, due to the weight, when it breaks the bone...(bone moves when broken, causing the friction.) But I could be wrong...

[Nathan Palenski]

I could be wrong, but I think those create the friction, due to the weight, when it breaks the bone...(bone moves when broken, causing the friction.) But I could be wrong...

Go to the hardware store and buy a sleeve of single sided razor blades. Fool around with one for about 10 minutes and get back to me.

[Brendan Plavis]

Go to the hardware store and buy a sleeve of single sided razor blades. Fool around with one for about 10 minutes and get back to me.

I have an Xacto right here... can squeeze all I want... no injuries...

Have any more half baked comments you would like to add?

Please dont go off half-cocked...... it only wastes my precious time...