Tramming mysteries

This is kind of a weird one, I trammed my machine: spent a good long time on it, got it pretty close to perfect - close enough for woodworking anyway - then surfaced my wasteboard, to great effect. Best I’ve ever done! You really can’t feel anything on the surface. Very proud.

Then I attached a batching board to the machine, which I always do when I have production jobs that I will need to return to etc, and surfaced that.

You can see the results in the photo, spoiler alert: they’re terrible.

If you look you can also see the nearly perfect freshly surfaced wasteboard on the left in the photo.

Why would this happen? Did the machine untramm itself somehow? Any thoughts ?

Using my @wmoy style tram tester and feeler gauge, I’m finding .5mm difference between the front and back. Would that cause a ridge to appear that is approximately .2mm tall? Seems like rather a lot, doesn’t it? I wonder, can the bits get tilted slightly if there’s some dust in the collet or something?

In your pics, the ‘out of tram’ marks, cutting slightly deeper to the rear than the front of the picture, fade out to nothing at the left edge. Does this suggest the batching board is bowed near the middle, and under cutting forces is ‘giving’ towards the middle - it’s not flat because the batching board doesn’t stay flat during cutting.
Just a thought. All of the above on square and level are good too, and that your base board surfaces spot-on would suggest that your machine is quite true.

Im not sure if my eyes are playing tricks on me but as Andy says I also see the left side of your batching board appears flat. But I feel like I’m seeing alternating stripes. One is high, next is low, and repeating. Both sides of the higher stripes appear to be high.

If you confirm it is this way then I’m not sure it’s a tramming issue as that would cause the ridge to be on one side of the cut and be continuous throughout the board.

Exaggerated a little more but does it look like the left or right side of this pic?

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Check out my doc on spoil board towards back is section on flattening spoil board.spoilboard_considerations.pdf (1.3 MB)

I think it’s more like the left side. The grooves are not angled noticeably. And they do seem to disappear at the left side. Super weird.

What bit are you using along with speed, depth of cut, and step over?

It looks like a 1in bit to me with a full 1in stepover? Maybe try .5in stepover and see the results.

I use the Whiteside 6120 1" 3 cutter. Most any 1" bit will work with the settings from my custom tool database.

You can add a tool and use these for the 1" fly cutter.

number vendor model URL name type diameter cornerradius flutelength shaftdiameter angle numflutes stickout coating metric notes machine material plungerate feedrate rpm depth cutpower finishallowance 3dstepover 3dfeedrate 3drpm
601 whiteside 6210 Fly Cutter end 1 0.125 0.25 0.25 2 3 0.25 0 Shapeoko MDF 10 80 16000 0.01 1 20 80 16000
602 Sugelary X002JUT7TF Fly Cutter end 1 0.125 0.25 0.25 2 3 0.25 0 Shapeoko MDF 10 100 16000 0.01 1 20 80 16000

The Sugelary is a generic 1" fly cutter from Amazon. Whiteside suggested 100 IPM but I set it at 80 IPM to be safe. My measurement is Imperial not Metric.

Roll your X, Y, and Z axes while the machine is off and see if you feel periodic bumps. You may have some crap stuck in your V-wheels, or some form of physical damage to one of them. Either a flat spot or a crack.

Also, are you using a dust boot?


From the pictures it looks like the left side (closest to Y-left rail) the toolpath/marks looks like they flatten out and fade into a level wasteboard. Seems like you also confirmed that the tool marks also kind of form a square wave pattern but does it get more pronounced as you move closer to the Y-right rail? Is it possible that a v-wheel on the right side is loose and the generation of the square wave profile is because a wheel and the eccentric nut is rotating freely with the wheel which could ever so slightly be shifting the right side of the gantry up and then down at each stepover (or like Winston pointed our crap stuck to a wheel or flat spot most likely on the right side)


I’ll add my money to the “something is up with a v-wheel” bet, which tend to induce a different effect when the router is travelling to the left or to the right.


I’m with @wmoy, @Julien, and @Caffein8ted

I see a belt drive z-axis that makes me think the pressure from the brushes on your dust boot (if applicable) is causing some wonkiness. Or the lower wheels on your x-carriage need cleaning/tightening.

From the first picture it looks like every second pass is cutting deeper along one edge. If your clearing path is cutting both directions (one pass to the left and next to the right) it is probably the wheels on that x carriage being loose, one being noticeably looser than the other.

If you want a guaranteed crowd sourced fix, post up a video of it cutting another piece and some eagle eye will point out exactly what is off…

Edit: wouldn’t hurt to check the eccentric nuts of the vwheels on the z-axis, itself. The rotation could easily be happening there.


Thank you all so much for the help! Man I really love this forum.

Once I got back in the shop today, I cleaned the v-wheels and rails very thoroughly, ran it again, and got a much better result:

Note this photo was taken halfway through the resurfacing process.

It’s not quite as smooth as the main wasteboard, but I think that’s very likely down to the batching board flexing slightly. And anyway it’s well within tolerances for the next thing I’m running.

Thanks again, all!


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