looks like they may have built this machine

http://shop.cncdrive.com/index.php?categoryID=89

The table is aluminum. Ive attached pictures of the motor control box which still works amazingly...

Again any help I can get is great as I dont know very much...

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I question the 2,000 pound estimate, but from what I see, I would definitely add some angle bracing in the base. Either that or anchor it to a wall. I think you'll find a lot of machine wiggle from higher travel speeds to feed speeds. I'd also would recommend side plates on the z axis aluminum. You'll get flex in that plate because of that long reach. Especially when you put on a spindle. It will be an okay starter, but as said, don't put all that money in it. Keep it as a second machine when you buy a real commercial machine.

Thanks Rich. I did say almost a ton. my guess is between 15-1800 lbs. Behind that aluminum plate on the Z are a pair of Hiwin Rails as well. I really dont see a lot of flex happening there, but maybe. also there are two more long rows of boxtube under the table that are not seen, adding to weight and rigidity. So far the only time it has wiggled from start,stop at speed is before I leveled the legs to the floor. I do agree that there is a limit to what I should spend on this. But as far as i can see, if I keep the total price(including original purchase) under 12k, im in the win. There are no american made machines in a 4x8 in that price range, and from what ive seen in shopping for used, is that the big Iron all need repairs and upgrades just like this little guy, only all of their parts are proprietary and more expensive. Not to mention most of them appear to be used pretty hard in a production environment. Also theres no way a biesse rover will fit in my shop nor do I have near enough power going to my building.

I've run a CNC for around 20 years, I think you said you haven't. But if you don't trust my experience, that's up to you. A rail doesn't add strength because it's thin. You need width of material to add bending strength. I was an engineer at Caterpillar for 16 years, I know structural design and finite element analysis to engineer strength. I also ride bicycles for a hobby. I know that if there is no triangulation in the structure, it's not rigid.

Rich. You are correct I have zero experience,that just didnt strike me as a bending point... so you are saying I should add an aluminum plate gusset to the face of the router plate at a perpendicular angle to make the plate itself more stiff?

You can build your own relatively inexpensive through vac hold down system with sheets of 3/4" PVC (think Azek) and vacuum motors from Lighthouse enterprises.

I set my old Precix router up with four separate PVC grids and a vac motor below each one. Four switches allow me to run any of the 4 zones I need.

This is just a fun retirement machine but I am confident that shy of heavy 12 hour a day/6 or 7 day a week use the vac motors will do the job well for many years.

BH Davis

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A couple more photos.

Also, I wouldn't worry too much about rigidity of that table.....at least until it shows to be a problem. Looks plenty solid to me for that class of machine..

BH Davis

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Thanks B.H. do you happen to have any links to info on building a vac table. Is there a file that I could download for cutting the grid ect...

Also, why is plastic better for the grid, as opposed to HDF or something like that?

You need a sheet product that is non-porous for the grid. MDF, HDF etc. while inexpensive are porous products. PVC is not porous. So while PVC is more expensive than the fiber based products it is substantially less expensive than aluminum or phenolic which are both non-porus and machinable sheet stock.

I'll see what I can dig up for you with regard to product links and cut files.

The shop vac motors have been widely used for hold down in the ShopBot world for many years. I have to confess that is where I originally learned of them. I've made a couple systems with them and both are still running strong.

BH Davis

Here is one photo of the completed grid system. You can see more photos at the link below.

The vac motors are available through Lighthouse Enterprises. The motors he sells for this are his own design with long lasting brushes. Ballpark $135 each. I used 4 of the LLH7123-13 motors at 230v. One is mounted below each of my 4 independent zones.

https://www.centralvacuummotor.com/lighthouse.htm

Ward Bartsch is the fellow and he's very helpful.

A bunch of cut files went into making the grid panels and vac motor brackets. Let me know when you are ready and we can get together on the phone to figure out if any of these will be helpful. I think they will as UCCNC uses basic G-code which is what all these file use. I'm right now in the process of building a new UCCNC based control for my router. I'm at the point of tuning the servos so am pretty close to its being ready to run the machine.

BH Davis

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Vac Hold Down Photos