Weird stripped pattern in wasteboard?

Hello all.

So after following @wmoy’s great tutorial video on squaring, tramming, and calibrating my SO3XL I’ve run into a funky looking problem.

When surfacing my wasteboard (again, thanks to @wmoy’s video(s)) I’m setting a weird pattern along the left extreme of the surface.

It looks like every other “stripe” is higher than the previous one:

What’s weirder is that it only appears to be happening on the extreme left of the board. The middle looks fine:

As a point of reference, this is where it’s happening on the wasteboard:

After doing some surfacing tests on another section of MDF, I tweaked the tramming as I had some front-to-back unevenness, but this appears to be something else.

Has anyone encountered something like this?

Something mechanically going on. Check wheel tightness on the left carriage front to back, and if the spindle carriage is fully solid left to right (can’t cock over)


@Rodrigo - Welcome to the community! I had a very similar problem when I attempted the first leveling passes on my wasteboard. What fixed it for me was taking very shallow cuts, like 0.002 with each pass. Yes, it took quite a while to get it done, but its flat way beyond my requirements.
I also sealed the wasted board with spray-on poly after I discovered that humidity changes would expand the outside edges more rapidly then the center.

My guess is something on your Z carriage is loose. Does the problem remain if you use climb milling only?

Climb milling should put less stress on the spindle & z carriage so you could start there.

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Thanks for the quick responses!

I’ll have a detailed look at stuff and see if anything is loose or wiggly, as that seems like something that could come from it not being even/sturdy when moving left to right.

Dust boot brushes aren’t touching the wasteboard are they? If so, lift the dust shoe slightly to eliminate contact. Also make sure you’re bumping the shoe bracket into the end of the rail travel.

I had the same problem resurfacing; found that my router was not square to the spoil board. My front/back were not vertical, so shimmed the router and got smoother results.

There is some contact, so I’ll be mindful of that.

I think I found the problem. In going back upstairs to the machine and giving the Z carriage a good wiggle, I found a tiny amount of play. I tightened up one of the “inner” eccentric nuts to get rid of the play and it feels rock solid now.

Tomorrow I’ll try giving it a new haircut with it all rigid.

Hmm, that’s good to know. It gets pretty humid here in the winter (Portugal), so I’ll keep an eye on that.


As an aside, what are people doing for MDF wasteboards in the EU? The thickest I was able to find at a local depot

was 16mm, which works, but I’m already getting really close to the embedded hardware underneath and this is from just surfacing it the first time.

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As I understand it HDF Valchromat should be readily available to you in Europe. It’s far superior to MDF in terms of stability and humidity resistance. It also mills amazingly well. Caveat, this is just my impression from reading online, donno how easily you can get it in Portugal.

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So to bring it to conclusion, I had to give it another 1mm haircut in the end to get the weird ‘stripes’ completely removed, so this wasteboard will not have a very long life of resurfacing ahead of it before it becomes useless, but live and learn.


And to round out this aside, I went to a bigger hardware store (Leroy Merlin) and they had 19mm (3/4") stuff in stock. So next time I’ll go with that instead.

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Comically, I found this, this morning about HDF Valchromat.


Hah, such is the “world economy”…

I’ll look into that next time I buy stuff too, but I didn’t see any of this at the local shops, and not sure it’s worth special ordering and/or shipping something like this for just a wasteboard.

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