[jevs]

Do the CAMaster routers use a hollow Aluminum tube for the gantry?
If so, does anyone know the dimensions and how thick?
Does it appear to have a machined face for the linear rails or just a raw tube?

[ger21]

I think this is a custom R&D machine, but it looks like a machined aluminum tube, either 1/4" or 3/8" thick??

https://www.youtube.com/watch?v=8ohW...ature=youtu.be

[jevs]

I wonder where a person could buy some of that tube and if it comes like that or they process it further (face it flat).

[ger21]

Here's a 4"x6" tube.
Order Aluminum 6061 Rectangle Tube in Small Quantities at OnlineMetals.com

I would think that it's lightly surfaced.

[ger21]

McMaster Carr has a 3/8" wall 5"x8" tube, but they only sell it in 3' and 6' lengths.

[jevs]

$390 for 6'. 5x8 is overkill for me though. I need something less than 5" wide. I found a lot of stuff with 1/4" wall thickness, but it gets hard to find anything with a larger thickness.

5x8 is larger than I need. A smaller width would be better. It is hard to find anything thicker than 1/4" walls.

I wonder how strong a 2x6 1/4" wall would be for a gantry tube. Also, I have no means to surface something that large.

It sure would be nice to see some routers in real life to get some ideas and measurements.

[cabnet636]

I think this is a custom R&D machine, but it looks like a machined aluminum tube, either 1/4" or 3/8" thick??

https://www.youtube.com/watch?v=8ohW...ature=youtu.be

this machine while built by a CAMaster manager is a personal machine, Camaster has a custom machined Gantry but it is Flattering that it is so well accepted ! the base of the stinger has been copied by another company as well.. show who is doin tha thinking !! you will hear compalints about the price when compared to average quick money machines, but they don't chinch on the quality

[jevs]

I just need something rigid to make a gantry out of and it is darn hard to find surprisingly (within a reasonable price range). Basically I need an accurate aluminum tube, which it just so happens CAMaster seems to use on their routers. Another company uses their own extruded gantry, which again is no help to a DIY'er.

It appears the one in the video above may be a 3" X 8" tube with a 3/8" or thicker wall. A size I cannot find on the web and....I would rather have a 2 to 2-1/2" wide and 6-8" tall which I can find, but only in 1/4" wall. I would like a little more meat than that.

I could use steel, but I think this will be too heavy for my all aluminum machine. I may have to think of a way to use cast tool plate and then brace it, but the tube would be cleaner and easier.

[islaww]

Jevs...
I can answer your questions, I think. First off that linked video is to one of my machines. I work for CAMaster so I had the ability to purchase the aluminum tube AND have it machined. The tube is 4" by 8" with a 1/2" wall. Since they are an extruded tube they MUST be machined, as there can easily be .080 to .100 variation in straight or twist across a 5-6' length. That is the spec the mfgr gives. We machine all 4 sides to ensure that they are straight and square to each other and to remove twist. We machine reference datums for the linear rails and drill and tap numerous holes for mounting components to the beam. Very few, if any raw blanks are straight enough to use as we get them. We feel a few hours of machining is worth it in the long run.

As a DIY, if you wish for precision you must machine your parts. Aluminum tube and extrusions all have a "spec". So many thousandths per foot of variation. That is for dimension, straightness, perpendicularity and twist. Twist is usually the biggest problem with extruded product, and as such usually has the largest tolerance. Most extrusions large enough to qualify as a CNC gantry may have an allowable twist of 1/10 degree per foot. This "acceptable" tolerance means that even if the gantry was strait, there could be 1/8" shift by a cutter over 5 feet. That results in the vertical axis being plumb on one side of the gantry and 1/2 degree out at the other. We similarly mill our frames to ensure the straightest possible platform we can deliver.

I hope this helps

[jevs]

That does clarify things. Thank you.
I decided to stick to tool plate since I don't have a mill that big or access to tube like that.