Smoothing out wasteboard

I have read a bunch about making sure my Z-axis is tight and that the end of the router is square with the wasteboard. I wanted to share an illustration and see why it may be cutting perfectly in the middle of the wasteboard but as it gets towards the left or right side of the X axis it starts cutting my wasteboard with slight ridges. I understand the tramming of the router aspect, but just figured if it was squared up and cutting well in the middle it would across the rest.

Anyone experience this? I surfaced it with a 1" bit and 50% crossover.

Are the ridges on the right and left side mirror images of each other?

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It doesn’t appear so. The high side (ridge) is on the right of the cut for both the left side of the wasteboard and the right side of the watsteboard. It is also a little tough to tell since I hit it with some sandpaper afterwards :slight_smile:

It also doesn’t really seem like it gets more pronounced as it goes over, it just sort of starts being visible after about 10-12" from the center. The middle from top to bottom is smooth to the touch.

Sounds like you may be out of tram in the left to right direction. Take a cylinder (I used my coffee cup) and tilt it to the right; vertical motion will leave ridges directly related to the tilt while horizontal motion will leave shallow scallops that may be barely perceivable.

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I tried to make sure the tramming was correct beforehand. I guess my question is why would that only cause those scallops marks on the outside left and right portions and not in the middle 12" of the wasteboard. I assumed it would have more uniform for the whole cut. I had tested a small area on test wood before I did the whole thing and it was smooth, but I guess that was just because I positioned it in the middle.

It’s related to the direction of movement relative to the tramming error; movement perpendicular (the sides of your drawing) to the ‘tilt’ will result in ridges while movement parallel (the center of your drawing) to the ‘tilt’ will result in shallow scallops which will not be as obvious.

edit: If you use a 1.000" surfacing bit that is 0.004" out of tram and a 50% (0.500") stepover the perpendicular ridges will be 0.002" high and the parallel scallops will be 0.00027" deep. Almost a factor of 10 smoother.


First, make sure your spindle is trammed in both X and Y direction, I use a machinist square to check. Second, I would recommend you reduce your stepover to no more than 40%.

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Thank you both for the suggestions. I will check the tram again and reduce the stepover when I do it again.

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Check that you’re not getting flex in your wasteboard too… That could explain the issue

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check your v-wheels at the bottom of the z-axis plate. Those screws work loose real easy. Should be “Loc-tited” …or remove the stock screw and replace with a longer one that you can put a lock nut on beyond the eccentric nut.

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