Z-depth not as advertised, where is the fix?

I am a new user of the Shapeoko XL. I bought the machine in March but due to COVID interference I just got around to using it for actual projects recently. Or trying to anyway. My machine has the Z-plus upgrade.

That being said, this machine does not perform as advertised. Specifically, it does not have the Z-depth that was listed in the specifications as purchased. I bought this machine specifically to allow for production of parts of a certain height. I found this thread:

…which essential has Carbide3D admitting they intentionally broke the original design by going out of spec and then pretended this was a feature.

On top of that apparently the included wasteboard, which is called exactly that in the documentation, is not a wasteboard. The Z-Plus upgrade means no bit can actually reach it. Its already kind of ridiculous this included board does not have any at leasn minimal threading for work holding, but now it is impossible to even modify it for that purpose.

So I went out and bought some 3/4 MDF to make a wasteboard to go on top of the wasteboard so this machine is even usable. Then I discover doing so means you can’t dublicate the included board because now the hieght of the work plane is above the clearance of the Y-axis rails so you can slide them underneath to section mill. I need this because I intend to use the entire advertised cutting area and the wasboad sections ouside of it are required for workholding (I bought it specifically because of this). Oh but there is more! Even with the aditional 3/4 inch of MDF no surfacing bit can each that, nor will the included #201 bit if you recess it into the collet entirely (also known as the safe way). So you actually need TWO wasteboards on top of your waste board, eating into your Z-depth even more.

In the thread I linked Carbide3D provided a DIY solution to restore Z-depth to advertises specs. The only problem is that you need a functioning CNC machine to make it. And it’s in aluminum, which most buyers have no intention of ever getting into let alone have the skill to do so out of the box even if they did. I am one of these.

I am very disappointed in this product, which is currently useless. But I know it is NOT useless for those who have the pre Z-plus specifications available to them. Where can I get this Z-plus modification plate since I have no way to make it myself?

Cutting through the MDF baseplate and ruining it was never within the specification.

That plate can be made with a hacksaw and some files and a drill.

A better solution is a 3 layer system:

  • bottom: original MDF baseplate (sealed with spar urethane or lacquer) with some holes and if desired threaded inserts installed from underneath for adding threaded inserts to secure
  • middle: a threaded insert board larger than the working area by the reach of a clamp which has holes in that border area which match up with the threaded insert holes in the bottom layer to secure it, a grid of holes in the working area field for threaded inserts installed for workholding, and additional holes with threaded inserts to secure
  • top: a spoilboard the size of the supported working area plus the diameter of the endmill used for surfacing along X, and endmill radius along Y, (with a matching radius at the back corner) which has holes in it to match the threaded insert board for workholding purposes (these may be drilled at need) and holes to secure it to the threaded insert middle layer

Maybe if the thickness of those layers were listed it may help in the building of the work area …?

Thickness can be whatever is convenient.

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Is this not an official tutorial from your site showing customers how to turn the stock baseboard into a threaded insert workholding board?

This is in fact what I was trying to do that prompted me to discover the inadequacies of the new Z-plus version. Lets move beyond pretending this is not a change to the machine’s operation.

I agree that having layers CAN be beneficial as a precaution if your project has no need to bottom out the usable work volume. If you want to utilize the entire advertised Z-depth of the machine you should be able to reach the stock spoilboard.

The idea that you should not be able to reach the shipped with machine base (labeled a “spoilboard” in the assembly instructions), for modification or otherwise, is obviously not as intended as the original version did so just fine and you make videos showing it being done. The fact that the fully recessed shipped with #201 bit is still 3/4" above the stock wasteboard at full Z-plus carriage depression means you can’t even make the intermediate theaded board you just suggested above. You need at least two 3/4" MDF boards on top of the shipped board to even be able to make what you suggest.

The idea that it was intended that the stock machine required 3/4" and above stock to be used at all is obviously not intended. This is an oversite, and one that is not in line with the advertised performance of this machine. This machine can not be used out of the box, whether optimally or otherwise. Do you say this anywhere in your advertising or store page?

So, back to the original question: Where can I get get the Carbide3D recommended solution?

Hmmm… you have made some interesting points. My interest is that I am awaiting my SO3 standard to be delivered. Is the linked DIY Shapeoko Wasteboard not going to be doable in the delivered form of the SO3? I was rather hoping to follow the examples given.

This actually threw me when I first got my machine. Then I learned that you are actually supposed to adjust the stick out of the bit to fit the job you are trying to do. For instance if you are trying to machine the top surface of an item that is close to the built height limit you will want the cutter as far up into the collet as possible. If you are trying to machine something like a waste board you will need to have the bit stick out further. On my Makita router I can stick my #201 bit almost an inch and a half up into the collet, but it only needs about half an inch in the collet for it to be securely gripped.

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That won’t help much with most 1 inch flattening bits that are used to surface the needed work board/spoilboard.

An inch and a half or one half inch… at high speeds this has to be no contest for bit security and rigidity. Someone far smarter than me should be able to say something about the deflection induced when the bit is sticking out from the collet a further 1 inch. I have seen this referred to as ‘stick out’ elsewhere. As an engineering entity, it feels (to my mind) as if the risk of producing an issue (chatter or breakage) when cutting is increased by holding less metal in the collet and permitting more flexibility at the endmill tip.

The thing is, it’s a pain to directly surface the MDF baseplate — one ends up with a pocket with rounded corners at the back, which one then has to fit things into.

It makes a lot more sense to have a top layer which is a sacrificial spoilboard and which can have as many or as few holes as need be, and a middle layer which has threaded inserts in it, but doesn’t get cut into (because installing threaded inserts is a pain).

Hi Will. Is there an issue with Z height for new machines? That is to say that an SO3 machine with say… a surfacing bit cannot surface a spoilboard of 18mm in depth, that has been placed on top of the baseboard, where the bit shank does not permit an extra inch of stick out? Thank you.

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Is the spoilboard/baseboard height the issue, or the travel on the z-axis?

It took some searching to find out the “z-axis travel” for the Shapeoko since it’s omitted on the Shapeoko page, but on the “buy this thing” page it’s 3" for regular Shapeoko’s and 4" for the new Pro model.

So long as there is 3" of travel in the z-axis, does it matter what height the bottom of that 3" is from the top of the base/spoil/bottom board?

I suppose the travel relative to the gantry is relevant if you’re interested in cutting thick stock?

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On my Makita, the collet is only 0.6in long so even when the bit is sticking out an inch and a half the collet is still making full engagement with bit. I would never run with the collet making partial engagement. Also you should probably check out “long reach” endmills.

You are however correct about the chatter. The more the bit is sticking out from the collet the more chatter you should expect. You should adjust your chip load to compensate. One of the nice things about a high speed router is that you can run at higher RPMs and take smaller cuts thus reducing the chip load while still maintaining a reasonable feed rate. If however you have to take higher chip loads, then I am afraid you bought a DIY light duty CNC Router when you probably should have bought a CNC Mill like a Tormach.


Yeah… I realized this just after I posted my puzzlements. It has to be able to descend 3" from the lowest fixed item.

I can not answer that, I have the belt drive only and no experience with either of the upgraded z assemblies. Just a LOT of posts at this site expressing the same issue.
It seems from the posts and replies that with a z-plus or HDZ a person needs to assemble the machine as instructed, then add a 3/4 inch intermediary board on top of the supplied spoilboard, plus another 3/4 inch board as a spoilboard.
From the readings here it looks as though the new work surface will be about 2-1/4 inches thick???
The spoilboard on my shapeoko is approx .75 inch below the edge of the front frame and can be reached with a 1/8 shank 0.032 bit.
I was strongly considering the upgrade z axis until these " Can’t reach the spoilboard" posts started showing up.

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Sounds pretty confusing. I only own a Nomad, which luckily has the moniker 883 which handily describes the 8x8x3 volume it supports.

Surely there is something somewhere which specifies the usable cutting volume for a Shapeoko?

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The Shop page: https://shop.carbide3d.com/products/shapeoko3 has:

  • Shapeoko 3: Cutting Area: 16"(X), 16"(Y), 3"(Z)
  • XL: 32"(X) x 16"(Y) x 3"(Z)
  • XXL: 32"(X) x 33"(Y) x 3"(Z)

I might add to the original poster;
After you get the spoilboard worked up you can raise the router in the mount body if you need more room… that might get you back to the clearance you need.

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Thanks for the helpful response. Where I am sitting right now is this: 18mm Spoilboard as the middle layer, then another 18mm wasteboard on top equates to 38mm in depth. That is the equivalent of 1.496 inches… (plus the depth of the baseboard and taking the total wasteboard/spoilboard depth to 2¼ inches?) which is as good as one and one half an inch, as near as makes no difference. If the Z height available on the standard machine with a Z plus mediated Z axis, that means the maximum height of workpiece is restricted to 1½ inches. That is a long way from 3 inches and I am sure the expensive surfacing bit I have just purchased will not permit me to stick it out of the collet another 1 inch.

I understand the point about long reach endmill bits and that may be helpful if I want to keep at least 2 inches of the available Z height useful for workpieces. I am, like many other people, restricted in space and my spend so unfortunately a Tormach is not in my future anytime soon (or at all). I am sure that I will be able to figure some sort of solution out but it does appear to be something of an oversight, where the travel of the Z axis is unable to cover the whole 3 inches.

Meanwhile, back at the ranch, the delivery of my machine has been put back to another date. I do hope the machine arrives soon.