Advice for spoilboard design: combination vacuum table with conventional workholding

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Hi there,

I’m thinking through my workholding strategy for my upcoming Pro 4896.

My primary use case is cutting full sheets of plywood, but I would also like options to do other types of projects like the occasional 3D carving in solid wood, surfacing/jointing large pieces of wood, maybe making table legs, or other things I haven’t thought of yet.

My current thought is to have the majority of my table be a horizontal work surface with a shallow vertical spoilboard at one end to allow me to do traditional dovetails and joinery in materials <1” thick.

I think vacuum table makes sense as the primary work-holding for the horizontal section since full sheets of plywood is my primary use case.

I’m thinking it might be interesting to try and sneak in some more traditional work-holding in the vacuum table - maybe a bit of t-track or some dog holes. I would however like to keep the ability to vacuum down a full sheet of plywood.

Has anyone seen or done a sort of hybrid spoilboard like this? I’d love to learn from prior examples.

Alternately should I just do a traditional vacuum table and then have a flat sheet with t-track that gets held down by the vacuum on top of it when needed?

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i think there are as many work holding strategies as there are CNC machines. It really depends upon what you are doing with your machine and what works best for your process.

That said, I don’t have a process. I’m a hobbyist with now a 4x6 Pro and a rotary axis. Every project for me, at least at this time, are one offs. Over the past year I have contemplated several strategies, milled several holes for clamps and dogs, peppered the surface with screw holes, and installed strategically located T-track. Ultimately I have developed a system where I don’t actually use the spoil board. Instead I use the spoil board as a base for many auxiliary clamping surfaces. For inlay work I have a piece of MDF with 1/4” index holes at opposite corners and a series of recessed holes for 1/4-20 socket head screws to bolt it onto the spoil board in a repeatable position. I have 1/4-20 threaded inserts installed from the bottom so all access to mount is from the top. This allows me to install squaring pegs/dogs, drill it full of holes, surface it every time I install it, and easily replace it when it wears out. I also have a 2’x4’ Airweights vacuum table mounted in the same way. When I do smaller jobs where I need to make several of the same item, I use a scrap of MDF milled as a fixture board to repeatedly clamp items to run jobs over and over. If I dig into any of these fixtures (aside from the vacuum table) they can be easily replaced and the main spoil board remains undamaged. Just a series of strategically placed holes with threaded inserts and indexing pin holes. If there are projects where I need the full surface of the machine I can simply unbolt the various fixture plate and use the primary spoil board, then bolt the fixture plates needed in a very repeatable way for the next task.

My advice would be to use your machine without investing a lot of money in hardware that you may find you don’t need. I was scared to death of making mistakes when first starting and destroying my spoil board, and I did make those mistake. Just doubling up your spoil board will allow you to play around with screwing things down and adding holes for dogs and such. When that get worn out just toss it and screw down another one. If Z height isn’t critical for you and you can spare an extra 3/4” of spoil board thickness, this can save you some frustration. You’ll eventually find out what works for you and your operations.

1 Like
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Agreed. I thought I would do mostly plywood, but I don’t. Lately I’ve been doing mostly carvings, where I need access to the whole top but the parts are too skinny to vacuum. So I have a row of pins along one edge of my spoilboard and I use wedge clamps to hold the edges of the boards. I still just screw into my MDF because I haven’t decided what my long-term solution will be, so I’m working as if this one is sacrificial :slight_smile:

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I lock down my spoil board to the vacuum part with inserts/bolts. My spoil board is in multiple pieces. I can remove part of the spoil board and bolt in a fixture piece, which has different hold down types.

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This is the approach I have started using as well.

On a 5x10 machine, I have a 4x8 section that is MDF vacuum table powered by a home built hurricane like set of vacuum motors. This works great for full 4x8 or 5x5 sheets

The 6 inches to either side is T tracks, though I rarely use those the way I have them configured.

Within the vacuum table I have brass threaded inserts installed that I use to hold down fixture plates (plywood) or AirWeights (yes, I have a vacuum table on top of a vacuum table). Plywood fixture tables are aluminum T-Track, Microjig Microfit dovetail slots, and dog holes with 3D printed dogs (or a combination thereof).

I screw section(s) down (they are 23.75x23.75” square), square them using the Ex controllers coordinate system rotation (my new favorite feature) and am good to go for small parts.

Need to do a 4x8 sheet? I just remove the fixture plates in a matter of minutes.

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Hey — we just launched an Avid-specific version of VersaPod.

It’s a modular vacuum pod system that’s extremely capable, affordable, and easy to integrate on Avid machines. The modular layout gives you a lot of flexibility without locking you into a permanent table design, and it lets you handle everything from full sheets to solid wood while still leaving space on your table for vertical setups. It’s worth a look.

If you’re interested or have any more questions about VersaPod, just reach out here or email me through our website.

Mike

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We’ve been using one of these setups here internally and they work great!

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Wow the Versapod looks really cool. Researching more now and will reach out if I have questions.

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Love the concept and website.

A couple of follow up questions:

  • Do you have any thoughts/recommendations on how the system performs with full 4x8 sheets of plywood?
  • Do I need one pump for each section (so 2-4 pumps for a 4x8 machine)?
  • What are the cons of using 2 of the 4x4 plates instead of using the Avid CNC specific plates?
    • This seems like it would be more cost effective for my setup.
    • Would it reduce the needed pumps from 4 to 2? This would also reduce the need to run more circuits to power the pumps for me.
  • How much power does each pump draw?
  • What’s the noise level?
  • For comparison I’m also looking at the Black Box hurricane and would be curious if you have any insight on how the noise level compares with all the pumps running.
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Thanks for the positive feedback! Happy to answer these — I’ll go point by point.

How does the system perform with full 4×8 sheets of plywood?
It performs very well on full sheets. For sheet goods, I highly recommend using the high-flow bottom ports, especially if you’re swapping between a spoilboard and a port board. That setup is optimized for airflow and gives very consistent hold-down across the sheet.

Do I need one pump for each section (2–4 pumps on a 4×8)?
The included pump is sized for one unit, but pump requirements are highly dependent on how you plan to use the system. For example, if you’re primarily using pods and cutting lower-leakage materials like plastics, a single pump can often support more than one unit.
Stacking pumps works well as long as you use check valves at each unit. I’m also happy to help spec a larger single pump for multi-unit setups. For reference, I currently run a Becker KVT 3.100 on a 5×10 system and it works great.
The key thing to keep in mind is that spoilboards are high-flow, while pods are high static pressure / high vacuum — pump selection really depends on which you’ll use more.

What are the cons of using two 4×4 plates instead of the Avid-specific plates?
The 4×4 units on the site are Universal Port Boards, which are designed to sit on top of an existing vacuum grid. The Avid-specific systems are purpose-built to match the Avid table layout and simplify setup when you don’t already have a grid in place.

Would this be more cost-effective for my setup?
Yes — if you already have a vacuum grid, the Universal Port Boards are typically the more cost-effective option.

Would that reduce the number of pumps needed (4 down to 2)?
Possibly. Pump count is driven primarily by total active square footage and material leakage, not just the number of plates. In many cases, fewer, well-matched zones can absolutely reduce pump requirements.

How much power does each pump draw?
Because the pumps operate under vacuum rather than pressure, the real-world amp draw is typically lower than the rated maximum. That said, I wouldn’t recommend running more than two pumps on a single 20-amp circuit. If you want exact numbers, I’m happy to take real measurements under load.

What’s the noise level?
Very reasonable — typically in the 60–65 dB range.

Black Box Hurricane comparison?
I don’t personally run a Black Box system, but regenerative blower-style pumps are generally louder and can’t achieve the same static vacuum levels as piston, rotary vane, or screw pumps. They can work well for spoilboards under the right conditions, but they’re a different tool for a different job.

Mike

11

Thanks for the details.

One more follow up question: how do you handle leveling the Avid specific ones to the machine? How hard would it be to have one of your systems on half the bed and a more conventional spoilboard on the other half and have both be in plane with each other?

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Great question.

Leveling the Avid-specific VersaPod Systems:
The simplest and most accurate way to ensure the VersaPod system is perfectly in plane with your machine is to first flycut your base spoilboard. The VersaPod grids are then installed on that flattened reference surface.
If you normally run three layers of MDF, a common approach is to replace the top layer with the VersaPod grids. That keeps everything indexed to the same plane. I’m happy to provide very specific installation steps if you decide to move forward.

Mixing VersaPod on half the bed with a conventional spoilboard on the other half:
It can be done, but it does add complexity. You’d need to independently level the screw-down spoilboard section to match the VersaPod grid height after installation, which takes some care.

My general recommendation is to cover the bed and use removable spoilboards on top instead. Vacuum will pull effectively straight through MDF for larger surface-area parts, and this keeps the whole table in plane without juggling multiple base heights. Using higher-grip gasket materials (like Allstar tile gasket) can further improve holding in those scenarios.

If you want, I can help you think through the best layout based on how often you expect to switch between sheet work, pods, and more traditional fixturing.