Extra layer under spoilboard

So under the assembly instructions for the Elite (pg 43), they recommended at least 3/4” board, no issue. They also then add
Note: For maximum stiffness it is recommended that you build up your wasteboard to a thickness of 2-1/2”- 3”. This will still give you approximately 3” of gantry clearance while reducing the moment force on the Router, Z-Slider and X-Rail parts. When building up your wasteboard to this thickness please ensure you use the Z-Sliders top mounting holes.

I am thinking of using a second 3/4” mdf so that I can slightly drill in for my dogs. Has anyone does and any pros and cons?

Hey Paul,

if you do it “for stiffness” like they say in the manual, then it’s clearly the wrong way to add stiffness to your table top. A wasteboard is made of MDF and MDF is not good for stiffness, and you don’t use your wasteboard to add stiffness to your machine bed. A thickness of 2.5 - 3" inch is perhaps necessary (or perhaps not even sufficient) if you want to build a table top made of MDF, but I would not recommend to build a table top of MDF as it’s not stiff, heavy, expensive, and fears humidity. While it’s ideal for wasteboards, an anti-torsion box made of 12 mm birch plywood is much more stable as table top (search for “torsion box” to see examples in this forum).

Generally, if you stack wasteboards on top of the other, you give away usable Z travel of your machine. On Z-16 assembly, you have 133 mm usable travel. You have three mounting positions of the Z-16 assembly so you can lower it to drill through, or mill into, your wasteboard or even table top (see pictures below). I find it more logical to lower the position of the Z assembly to drill the initial holes into your wasteboard, and to use the middle or higher position for normal use. In practice, for future new wasteboards, you could omit the step of lowering your Z assembly because you could put the new wasteboard or wasteboard slats on top of the old “wasted” wasteboard, drill your holes, and then replace the old wasteboard with the new wasteboard.

PS: Z-20 assembly as found on Elite Series has four mounting holes and 160 mm travel, but the same applies.

PS2: Is your machine base the QCW Frame?

Welcome to the forum!

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Thanks for your response. Very informative. Yes I am using birch plywood for my table top. I was just considering adding a second layer of MDF under my spoil board so I can go through with my bench dogs. Looks like I am going to proceed that way. Your information about the Z he was very helpful.
Thank you

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I ended up up going with using a layer of 3/4" plywood on the underside of the QCW stand. It was more to add quick-release sections to the frame, but it may (or may not add) stiffness to the system. Honestly, I really dislike the Foreman QCW stand over the table I’d built for my Jouyneyman, and I’ll probably eventually replace it with a stand made from heavy c-beams.

Ended up using some quick releases in conjunction with pieces of ipe and pine, mounted on the undersides of the plywood, to hold stuff in place. Gives me the ability to quickly remove spoilboard sections for access to a simple vertical mounting jig or the rotary axis which I’ve still not really figured how to mount.

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Interesting. So many different ideas out there. I’m just going to add an extra layer of mdf under the spoil board so I can push the dogs farther down with out penetrating mt bench plywood. Really not worried about stiffness. Bench is rock solid.

Thanks for your input!