Question about aluminum t slot plasma gantrys

[Jbrock]

Got a question for the ones who have built with aluminum t slot extrusions. I’m looking into using it for my build. I want to do an 8’x4’ table. What would the best option for the 8’ or better span for the X axis? Would the 1.5“ x 3” work ? Or would I be better off using the 3”x3”? The 1.5x3 comes in at 2.5 lbs per/ft. Whereas the 3x3 is 4 lbs per/ft. Thanks for any input.

[adbuch]

When you say "X axis" are you referring to the gantry or the sides of the table (assuming your gantry runs the length of the 8 ft. table)? Or are you saying your gantry will be the 8 ft. length?
David

[Jbrock]

I’m wanting to build a table like the spark robotic XR-84. 4’ Y travel and 8’ X travel.

[adbuch]

OK. Now I understand. I would think it might be better with the gantry running the other way so it is shorter with less weight if you were worried about the mass of the gantry/carriage for rapid moves. But I'm sure it will work as is. I would take a look at what Spark robotic is using for their gantry and mimick that as far as cross sectional area and mass. I expect either of the choices you mention will work. If you are ever intending to adapt a router or drill to your table, then I would opt for the more heavy duty approach. Otherwise - it doesn't really take all that much to support a light weight carriage and torch, so the lighter extrusion would probably do fine. I'm sure there others here who may do a more indepth analysis and give a more educated opinion.
Good luck!
David

[Jbrock]

Thanks for some input. No not planning on adding a router or drill. Im sure when either of those plunge into the work would create a crown possibly in the rail causing issues. I’ve looked at sparks rail and it looks to be maybe 3” t slot. Also it looks as though theres a linear rail mounted in each slot for more stability with the z carriage head. I personally like the 8’ plus wide opening for loading purposes.

[SRdesign]

It’s hard to tell from pictures but it appears to be a 2” x 4” rectangular tube on the x axis. They use v rail that looks to be riveted to the tube. Again just going off of pictures. They do use an aluminum extrusion under the sides with linear rail and gear rack. Possibly 1.5x3 or 3x3.

[acourtjester]

check out this guy's table made from aluminum.

[adbuch]

check out this guy's table made from aluminum.

Very cool Tom! His frame construction looks a lot like the Avid CNC tables that I have. At the end of the video, he forgot to stencil his letters - but still a very impressive build.
David

[dvn4life1972]

Been using t slot extrusion for my gantry a couple of years now. Zero complaints, although to be fair I’m not a big fan of the slots used as a mounting point. Don’t hate them, but I’m not a big fan either. If you are going to build a fast machine, I would recommend very solid but light gantry, and very stout/rigid/heavy table frame as a base.

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[weldguy]

Been using t slot extrusion for my gantry a couple of years now. Zero complaints, although to be fair I’m not a big fan of the slots used as a mounting point. Don’t hate them, but I’m not a big fan either. If you are going to build a fast machine, I would recommend very solid but light gantry, and very stout/rigid/heavy table frame as a base.

Good looking setup and good advice. Happy Thanksgiving.