Jointer Knives

[Thomschuck]

Fellow Genius’s,
I am having a bit of a problem with my jointer knives. I installed a new set. I am fairly confident that I have them all set spot on. I have been edge jointing Ash. Across the entire length of the edge I have uber small ridges. They are all parallel to each other. When I did the face of the Ash stock they are there again. I stopped worked and cleaned the new knives. I have this problem on the edge of 1” walnut as well. I set a spacer board against the fence to move my work away from the edge of my knives. Same results. Could it be in my alignment of the blades to each other? I think that would be odd but I can’t null the problem out. Could I have a bunk set of knives? I mean these are brand new knives. Thank You Much.
Thom Schuck
Portland

[JPG]

Slow the feed rate.

Are the 'scallops' closer together?

Using a straight workpiece. and manually rotating the cutter head, lower the workpiece until one blade just kisses it. Do the other two blades do the same?

[Thomschuck]

Tight and vertical. More like ribbing than valleys. Very uniform. My first thought was could it be the grain of the Ash. It’s super CVG and maybe it is pulling the softer wood out??? But then I THINK? it happened on my Oregon Black Walnut as well… That I am not sure of. I was all beat up and tired. I saw the problem and shut down. It’s just incredibly uniform. I have photos but I dont know how to post them up. You can really see the lines on your tablet. They will sand out with one pass for sure but it’s not right…..

[Thomschuck]

Yes. I used the ruler method advancing 1/8”. After I felt pretty confident I had a solid alignment I checked it with my new iGauging snap gauge. It told me I was dead on across the entire span of the knife. Maybe it is the feed rate? I was pretty tired. I will dig in deeper with some soft pine and then run some Maple or Oak thru it and see what I get. What blows my mind is how absolutely even the lines are. I am so tired I am now totally OCD and it screams GRAIN to me. Its just to symmetrical. I will give it a go tomorrow. I thought I would toss it down tonight thinking that maybe someone would spark up and call the problem. Less brain work at my end. Sorry, not being rude.

[Thomschuck]

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[Thomschuck]

Hey I did it! Can you see the photos? See the lines…?

[BuckeyeDennis]

Nice photos! If you run a fingernail down the edge of a jointer knife, does it feel perfectly smooth, or ever-so-slightly serrated?

Did you edge-joint that plywood with your new knives, perchance? I’m wondering if the glue lines may have worn tiny divots in the sharp edges of your knives. From the photos, it looks like the ridge spacing on the hardwood is about the same as the plywood lamination thickness.

[JPG]

Nice photos! If you run a fingernail down the edge of a jointer knife, does it feel perfectly smooth, or ever-so-slightly serrated?

Did you edge-joint that plywood with your new knives, perchance? I’m wondering if the glue lines may have worn tiny divots in the sharp edges of your knives. From the photos, it looks like the ridge spacing on the hardwood is about the same as the plywood lamination thickness.

Well that shows the importance of posting pix! So the 'ripples' are THAT direction.

I think the mystery is revealed.

Hone the knives.

P.S. Get a conical disc for plywood.

[BuckeyeDennis]

Hone the knives.

Being lazy, I'd probably just shift two of the knives by a fuzz (laterally, in opposite directions). If that is indeed the problem.

[chapmanruss]

Good Morning Thom,

Glad to see you are up and well enough to be making some sawdust.

You could try Dennis' idea of ever so slightly shifting two of the knives in opposite directions and thereby offsetting any possible "divots" the three knives may have. A simple thing to do without having to realign the knives by loosening the three screws on the wedge on one of the two knives at a time and bump the knife slightly offset from the one remaining in place. If it cuts smoother, than as JPG stated its time to, "Hone the knives." Likely that needs to be done anyway.