gantry rebuild question

[timberfab]

Looking into rebuilding my gantry and I'm thinking about using an 80/20 extrusion. my current table gantry is 6'2" wide with a 3"wide rail, running cncrouter parts linear carriages. I was thinking about using a 2 x 4 or 2 x 6 extrusion for the gantry and making my own connectors and end plates.

Does that sound reasonable?
Will it vibrate too much?
would i be better off using steel gantry?
Does this size even exist?
Where is a good place to purchase the extrusion?

[suttoncnc]

I have a piece 3" X 3" 80/20 that is about 5.5' long that I am thinking about using for my next machines gantry. It is really stiff stuff. I do not think that I would use it by itself for a CNC router operation but a CNC plasma all day. I also have used 3" X 6" 80/20 at work and it is tremendously strong. Not sure about the other sizes....maybe?

[WyoGreen]

Go over to Precision Plasma's web site and take a look at their gantry's, that should give you some ideas as to size, etc. I have a Precision Plasma gantry, and it's plenty stiff for plasma, and probably router too, but I've not used it that way. The idea with plasma is to keep the gantry as light as possible as the torch moves around pretty fast on thin gauge metal. I'd think steel would be a bit heavy for a plasma gantry, but I suppose there are machines out there that use steel.
I have a separate router CNC table, and I built it much heavier to withstand the side forces of the router. No way would it work all that good on plasma cutting thin gauge metal.
As far as source's for the extrusions, I remember going to several sites when I was researching building my machine, but can't find the links to them right now.

Steve


http://www.precisionplasmallc.com/

[Simko]

I am using 40-8016 (approx 3"x6") extrusion from 80/20 for my gantry. I just bought an 8.5' piece on Ebay from the seller below. I made an offer of $190 and it was accepted.

http://www.ebay.com/itm/LARGE-80-20-80m ... 3f500bc0e4

The same guy also has shorter pieces (around 5.3') for a decent price, plus you could always try the 'make offer' and see where it goes. He countered within 15 mins.

http://www.ebay.com/itm/80-20-80mm-x-16 ... 3f500bdd37

The 8016 sized extrusion is the same stuff that CNC Router parts used in their 'PRO' kits. It weighs 11.8395 kg/meter.

[LMKkustoms]

im using 1.5 x 4.5 80/20 for my gantry laid on edge so my torch travels on the 1.5 side if you look at arclights table they are using 1.5 s 4.5 1.5 side up

[Bigdogbro1]

The lighter the better with the strength required. I used a 8020 2"x4" by about 55" Y axis beam for my 4x4 machine. Entire gantry Y & Z (no X rails) assembly is under 50lbs. Plenty strong enough for a 2 lb. plasma torch.

https://www.youtube.com/watch?v=D-mfRaXM3Og

[timberfab]

thanks for the replies. I fabricated the last gantry out of steel and it has been great. just want to change the design a little. I Think I'm going to fabricate another gantry from alum instead of getting the extrusion. I have easy access to cheap alum in large quantities.