aluminum top

[Loudspeakerboy]

I was thinking the same thing about the bearings. The only problem that comes to mind is dealing with sawdust in the bearing path...

My 8020 will be here in a couple of days as will my vacuum fixture parts.

Pictures soon..

[Kryptik]

You'll already have the air there for your vacuum generators, if you are still taking that path. A small copper tube with some 4mm airline and a wiper seal should do the trick.
I already have air connected for cooling and clearing when doing acrylic work.
I'm thinking maybe a torsion box underneath to support the plastic base, which seems happy to assume the profile of whatever it is sitting on..

[Loudspeakerboy]

and we wonder why the machines aren't $10k.. I do enjoy the tinkering..

[Haltex]

When you play you pay

[rungemach]

For those of you who may be thinking of refitting an extruded aluminum top on your MDF top machines,
I found it helpful to allow the supports that the extrusions rest on to be somewhat adjustable by using elongated holes in the aluminum angle, and a micro-adjusters on the ends. There is a picture of this in the thread referred to earlier.
very simple and easy to do.

I used T-nuts into the plastic machine frame to eliminate the need for a nut on the inside, and since the t-nut does not spin, you can easily tighten or loosen the bolts form the outside surface with one wrench. This makes the initial leveling go easier and subsequent re-adjustment much easier as well.

Personally, I do recommend the heavier 8020 brand extrusions, as the Rockler blue extrusions are only 3/4 thick ( and were originally sold for fences). For a tabletop, the added thickness of the extrusion profile translates into much less deflection in the center. Get enough extrusions to go all the way from gantry side to gantry side, it's worth it.

BillK and others have run the numbers on the non-HD design and a perfectly flat and level table will still give you some variance in cutting depth due to the sag in the long bearing rods. An adjustable extruded table is a big step forward though. If you get your table dialed in at the corners , expect that the cuts will be a little deeper as the router approaches mid span of the unsupported linear bearings. That is a design issue.

bob

[Kryptik]

Starting to think about attaching a supported rod to the outer edges of the 8020 deck, then having the extra bearings attached inboard of the gantry supports....
Sharing the gantry load between these extras and the existing unsupported 20mm rods should allow extending out to 1200 on the Y. May need to upgrade the Y stepper.
Just thinking out loud

[DRMRDR]

I used aluminum angle iron in front and back of table. After aligning everything I then added extra bolts into main frame and the angle iron. The table is quite flat, but I get my best results cutting in the middle of the table were the deflection should be the same in each direction. That is why I wish NWC or rockler would give us some kind of solution to a updgade. It isn't like this is a isolated few machines.
Dave

[Haltex]

I have done more of the same upgrade on the Pro to include the 2 angle iron support in the middle across the short side. I used the 2030 exstution little stonger than the 2010 I am always thinking of things to make it better but I need to stop better sometims is not always the best

Have a good day guys

[Loudspeakerboy]

Better is often the enemy of good..