I think the ballnose would have worked great. I used a flat endmill expecting to use square foam, but the box store only had the backer rod. It has held up well so far.

Great question. So far, all the parts have stayed in place when cutting full profile cuts.

I usually cut full 4'x4' sheets on my machine, 1 hole have been more than enough for holding power, the reason I placed the hole near my X,Y zero is for when I do smaller projects I only have to close of the zone with foam sealer (sold in the widow dept. of your local box store). The main thing you need to do if you are using a shop vac like I am is to remove the filter and make sure you have max airflow, so use 2.5" hose instead of 1 7/8" size hose. I have not bothered to upgrade to PCV pipe and more zones as I have been happy with what I have. If it ain't broke lol. You can look at the files here if you are looking to make a table for yourself. www.etsy.com/your/shops/DanConnellDesigns/tools/listings?ref=seller-platform-mcnav

Good question, over time it seems like it'll start to lose suction as that happens, and those HPDE sheets aren't so cheap. I suppose you could use a porous intermediate mdf layer as a wasteboard on top of the suction grid.

I had the same question. I’m in the process of making a 22” x 22” vac table for my small DIY CNC machine. What I’ve come to conclude is the vac table is only half of the system. You need to add a spoil board on top of the vac table with gasket material between the two. Some of the more powerful vac systems can pull air directly through an MDF spoil board. I will be using a small 3.5 CFM oilless vac pump so I’ll have to do it a bit different. I’ll use 1/4” MDF as a spoil board on top of the vacuum plate/table with a gasket between the two. drill one 1/4” through hole in the center of the MDF spoil board and use door/window weatherstripping as a gasket between the spoil board and my project material. I’ve been experimenting for a week and I’m ready to start cutting the slots for the gaskets. Fingers crossed.🤞

@@thisoldman7142I’m a machinist and have had quite a few different cnc machines in my garage over the last year. I recently built a 60x80 router table and a vacuum table would be better yet. Anyways! You’re work surface, in this case the HDPE plastic. Set that as your Z Zero. That way. When your tool is at Z0.000 technicality you shouldn’t be cutting it. I use a tool setter so all my tools are always right where it should be!

If most of the work is done at the front of the table, it would make sense for the port to be up front.

@rpjames11 Yes of course, but just wondered how that would affect the suction toward the rear of the bed.

The location for the suction port does not really matter, unless you want to have "zones" you can turn on and turn off. My table is low and difficult to get the the center so I put the port where it was easy to access. I have does several carves with 4'x4' material all the way down to smaller than 12"x12" and the port placement has not been an issue with any of the carves. I have not done any small carves located at the back of the machine, my 0,0 is front left corner so small carve are always near to port.

I have files available on my ETSY shop, this link is for the Xcarve pro 4x4 www.etsy.com/your/shops/me/listing-editor/edit/1614929528/about But there are different sized files available.