Vacuum Hold Down

I have the X35 Woodworker with the QCW waste-board and I am working on a vacuum hold down system.

In looking at what I have done in the past, a lot of what I do tends to be smaller items and are toward the front of the CNC. With this thought, I am looking at building a hold down system that can drop into the current frame.

Here is a picture of what I have drawn.

My thinking is to mill the board, seal everything, install the PVC, install into the CNC (from the top). Then add a sheet of 1/2" ultra light MDF (skimmed on both sides). Most likely glued to the bottom piece.

I am hoping a Shop Vac will give me enough suction to make things work, my first experiment using 1" PVC did not do well. I am hoping 2" PVC will work better.

Does anyone have any thoughts on if this will work or is there a better way to get to the end.

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From the research I have done, most thoughtful designs for the table will work. The challenge and investment will be in a proper motor for the application. Here is one resource I had bookmarked, in case you have not seen it:
https://www.centralvacuummotor.com/shopbot.htm

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A shop vacuum may or may not not be able to generate enough pressure differential, depending on the surface area to which the vacuum is applied. But increasing the vacuum port size to 2" almost certainly won’t help, because the airflow is essentially blocked when in use. And you’d need a shop vacuum with a separate motor-cooling fan, so that the motor doesn’t overheat when the vacuum airflow is blocked.

Laguna has a very good video on making your own vacuum fixtures. They use a venturi vacuum generator, which operates off of airflow from an air compressor. In the comments below the video, they show a parts list (with links) that includes everything you will need, aside from the air compressor.

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All good information, I forgot to mention, I ordered the motor that is used on the shop bot.

I will look at the gasket material.

Hi guys,

I just got a 24"x24" vacuum hold down plate from makerjaceshop on etsy that he calls “Airweights”.

Here is the link to his product

So far I have it fixtured on my Elite Foreman and have it running off my pump I used for Rockler’s little vacuum clamps, which are also great for some types of workholding. The seller recommends a higher flow vacuum pump that my Gast one, but so far the setup is stronger than me or the OF :slight_smile:

The system is made of what looks like an expanded plastic with metal layers on the bottom plate, and he includes a sacrificial extra layer for fixturing when you want to cut all the way through the part.

Compared to his etsy photos, the new version is black and has a corner with isolated vacuum to use the touch probe and it appears to be a nice way to zero.

Ill post an update once I have used it a bit more, but so far am impressed.


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Wow! That is a super cool product. I saw it on their website, AirWeights .com and I’m considering it. I’m really curious what you think as you start to use it. Would love to hear how it goes.

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Do you have a 3d printer?

I made these a year ago or so. I dont use them often but they work great. The designer also made some out of hdpe so you dont need a 3d printer.

I run them with a vacuum pump used for car ac evacuation. Low cost, low noise. The total cost per clamp is probably around a dollar. I use some “foam rod” used for caulking as the gasket.

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You might set the scale up just a percent or two. I did crack a couple when I was tapping the holes.

Other than that though they’re pretty handy at times.

It feels a bit lighter than solid HDPE, and the base plate appears to be a sandwich of metal and plastic. The holes are set up for either wood screws holding to MDF, 1/4-20 bolts to a dedicated threaded hole or T-track. There is a threaded hole (with plugs) on each side, so I set mine up to connect to a vacuum pump plenum I had already set up towards the back of the machine. I am on travel so can answer more questions when I get back and cut a few more projects on it!

Those are practically consumable at that point! Much less expensive than what rockler offers! How has the auto AC pump done on long runs?

I dont use them all that much, but I have run the pump overnight a couple times for car AC. It seems to be durable enough.

You can always buy a nicer oilless one if you find it to be something you use a lot.