Streak Marks After Rotating Spiral Cutterhead Bits

It's common for spiral cutterheads to start leaving streaks after the bits are rotated. Prevention is laborious and time-consuming. October 3, 2009

I just rotated the knives 90 degrees clockwise on my Invicta 24" planer (spiral head). I am now getting streaks on all my boards no matter witch part of the planer I put the board in. The planer has never had any issues like this until I did this today. I did double check, and all screws are tight. Please help!

Forum Responses
(Solid Wood Machining Forum)
From contributor T:
Your problem is extremely common in the 4 sided square inserts, and a real pain. First take the blades out and with a soft bristled brass brush make sure all of the dust is removed from the back of the knives and the mounting slots. Then oil the screw and properly torque it.

Once again, it is a real pain. We sold our 4 sided knife machine 2 years ago and went with the 2 sided industrial rectangular knives. Significant improvement and no line issues.

From contributor K:
Contributor T is right, you need to clean every bit of anything foreign on the head and the knives. Just a speck of dust under the insert will cause streaks. It took me about 6 hours to do our machine (24" with a million knives). Of course that was the second time because the first time I was not careful enough and had the same problem you are having.

From contributor J:
Yup, very common. When you first get your head, it's factory set. As soon as you rotate them, you get the lines. Cleaning everything helps but you will still get those lines. You could send it out to get jointed, but that would defeat the purpose of having changeable (4 sided) inserts. Finding someone to do that might be hard, but until then, welcome to the lines.

From contributor S:
Yes, it is quite common. The bits are not in the same cutting circle. For spiral cutterhead, it is quite difficult to set all bits properly. Even the manufacturer will take hours to set one cutterhead in their factory.

From contributor W:
I'm getting the same thing on a Woodmaster 725. I thought it was the aluminum spiral head that came with the machine. I've gone to re-planing the boards on a Jet planer with straight knives to remove the streaks, but this isn't an option on boards over 15" wide with my setup. I now use the 725 to just size rough lumber down and live with the streaks in our situation. Lots of sanding on wider materials. Thanks for the info.