Z Carriage moves at +100mm

Got my Shapeoko XXL assembled today… fairly happy with the result… built it on my kitchen floor and the spoil board is within .5mm-.9mm across it’s entire surface!

One thing that concerns me… when using Carbide Motion to lower my Z carriage I can Visibly see it deflect around Z position 98, 99, and 100. It deflects in the -Y direction as its bottom most V wheels lose the track they sit on.

From my reading it seems like this Is a known design flaw?.. Should I modify the placement of my Z limit switch so that position 98, 99 and 100 are never reached during a job?

If your V Wheels are not making contact then you need to adjust them. Turn your machine off and adjust the V Wheels to be in contact with the track. The wheel should be in firm contact but not so tight that it makes the carriage hard to move. Just tighten enough so they make solid contact but not so tight that they bind the carriage moving it manually. All V Wheels on the Shapeoko should be tightened like this. You loosen the screw and use the eccentric with a wrench to tighten the v wheel. Hold the eccentric nut with the wrench while you tighten the bolt. If you do not hold the wrench in position the tightening of the screw will move the eccentric nut and change your adjustment.

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I snugged up the eccentric nuts, but the problem remains… it’s almost like the controller is allowing the cradle to plunge too deeply. There simply isn’t enough track for the V wheels to stay on; snug or not.

Heres a video I record that shows the deflection at ~100mm
https://www.dropbox.com/s/nnw6ngu5mfro62j/IMG_3027.MOV?dl=0

I watched your video and you have no bit in the router. If you had a bit in the router it would not drop so far. When you are cutting you will zero on top of the stock with a bit in place and usually if you are cutting something out completly you use tabs and the router bit will cut slightly into the spoil board. If you had a router bit in the router you would not drop so far. You are indeed right that your v wheels are coming off the track but you are plunging too low with out a bit to stop the router. If you put a bit in and you still have this problem then raise the router up slightly in the mount. The suggested mounting of the router is as low as you can get it. If you are cutting something taller you can also raise the router slightly to clear the taller object. Just remember that the object must clear the gantrys lowest level.

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You can run off the tracks, and there really isn’t anything to stop it. In practice, this won’t happen when actually cutting something because the material and tool will be in the way :slight_smile:

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heh, well I actually want to pocket something into the my spoil-board and then flip it so the thing I pocket was on the bottom of the unit. But I have a workaround for that’s slightly less dangerous/dumb.

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The spoil board gets consumed pretty fast doing things like that - the usual way to deal with that is stick a “supplemental” spoil board on top to use to make the fixture for your real part, then throw out/reuse the fixture later. It’s a lot easier than making a new wasteboard frequently- they’ve got a lot of holes in specific spots, and you can’t buy them from carbide3d. The really common way to deal with this is a second wasteboard on top that that can be much more easily replaced (which is how the t-track kit from carbide works). You can always take if off if you really need the extra Z…which seems to be far more rare than you would think!

Its like the old saying, the only dumb question is the one that is not asked. Everyone here has made mistakes and this is the place to get help. Dont feel like any question is dumb. As I said we have all made mistakes and that is the way to learn. The issues that you make a mistake on are the ones you will not make that mistake again. You should not be reckless but trying are the best lessons learned.

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