Router Gantry Beam strenght and vibration?

[Knut]

Seeing so many combination machines I just had to modify my 5' x 10' plasma table to do some routing. One design by PlasmaRouter appears to have a 6-8" tall gantry beam, not sure how deep.

PlasmaRoute CNC - CNC Router Table

Bought 2040 (2"x4") 80/20 beams 74.5" long for the plasma table and they doubled my order by mistake, told me it was a Christmas present.

I could stack one atop the other and have a 'L' gantry beam 6" tall and 4" deep approximately 6' long. IS this sufficient to resist bending or vibrating in routing wood? Video of their machines in action appeared to cut raised panel chamfers in oak resulting in a fine finish. My use will mostly be in soft woods, but it would be nice.....

The Mechmate has two parallel frame members riding low on the long rail axis with the router slung low and between them. That looked solid and potentially vibration free.

My question is will my 2x4 beam be enough in itself, or will the two of them be required to stop vibration and beam bending? Or should I go beefier yet?

Thanks,

[Med-Pac]

We used 3" x 6" 8020 on ours. 2x4 might be a little small, but if you made an l-shape......might work out.

Mike

[Knut]

A 3" x 6" 'solid' 8020 rectangle will have more a lot more resistance to bending, torque and vibration than my 6x4 'L' made from 2x4 8020. I do have some extra 2x2 pieces but not full length, that would give me 8"x6" in the center of the beam at least, but a full box section. Still worry about twisting torque with the beam being so long.

A plasma machine I carefully documented used formed aluminum sheet to make a light weight box beam about 7" square. Pop riveted together. I could attach a 10 ga aluminum 'L' to the back side of my 6x4 8020 'L' and have a nice box beam and the 8020 slots to attach things on the front and top.

I'll have to check the weight, if this gets too heavy , making the whole thing from 10ga sheet might be better. Using the slots for bolting things on is so handy though.

thanks for the input.

[Knut]

After reviewing one thread here with a fellow stacking his 3x3 to get 3x6, it dawned on me I could lay the 2x4s horizontal with a 2x2 spacer. That would end up being 4x6 I beam with reasonable stoutness and resistance to torque, especially if I box in the sides with some 10ga flat.

Thanks again,