[laserpilot]

Hi guys, After a lot of help from guys on here I have managed to get a small gantry style milling machine running for over a year now. I am glad to say it cuts alluminium superbly and operates faultlessly.

I have now decided to build a much bigger machine but MOSTLY for wood routing. The size will be 4'x3' Gantry style.

I am unsure for a machine this size should i use Aluminium or Mild steel for the base The design will be for a bench router so the base will also be the mounting point for the Drive rack as well as the Linear Guide Rail. . The choices are

1/ Aluminium rectangular box section, 6061T6, 5"x 2.5" with a 3/8" wall thickness, $40 / Lin Mtr
2/ Mild steel rectangular box section, 4" x 2" with a 1/4" wall thickness. $32 / Lin Mtr

The design will consist of 2 side rails about 50" long with 5 cross rails of app 30" to stiffen the entire structure. All joints will welded and I am also contemplating having it professionally built using a local welder who has a ground welding table large enough to fabricate the entire structure whilst being clamped down to this ground table. Cost for this would be $330.... Do you think this would be worth it?. I am seriously considering the Aluminium for 2 reasons. Firsty it has twice the wall thickness and secondly as it will only be machining wood, the stresses should be less than a milling machine. What are your ideas on this also

Thanks in advance for your advice

[wizard]

Hi guys, After a lot of help from guys on here I have managed to get a small gantry style milling machine running for over a year now. I am glad to say it cuts alluminium superbly and operates faultlessly.

I have now decided to build a much bigger machine but MOSTLY for wood routing. The size will be 4'x3' Gantry style.

I am unsure for a machine this size should i use Aluminium or Mild steel for the base The design will be for a bench router so the base will also be the mounting point for the Drive rack as well as the Linear Guide Rail. . The choices are

1/ Aluminium rectangular box section, 6061T6, 5"x 2.5" with a 3/8" wall thickness, $40 / Lin Mtr
2/ Mild steel rectangular box section, 4" x 2" with a 1/4" wall thickness. $32 / Lin Mtr

That isn't a huge price difference so it is probably up to you with a consideration for the tools you have available. Locally the price difference would be significantly different so it is somewhat a no brainer to go with steel. In the end either material needs flattening for ultimate accuracy. One other consideration is that Steel is easier to weld.

The design will consist of 2 side rails about 50" long with 5 cross rails of app 30" to stiffen the entire structure. All joints will welded and I am also contemplating having it professionally built using a local welder who has a ground welding table large enough to fabricate the entire structure whilst being clamped down to this ground table. Cost for this would be $330....

Not a bad cost there. Such a welded structure though should be stress relieved and most likely you will need post fabrication machining to achieve flat surfaces for your linear components.

Do you think this would be worth it?. I am seriously considering the Aluminium for 2 reasons. Firsty it has twice the wall thickness and secondly as it will only be machining wood, the stresses should be less than a milling machine. What are your ideas on this also

Thanks in advance for your advice

At the prices you suggest Aluminum would be good. The biggest issue with aluminum in my mind is screw holding especially if the frame is welded together in a pro shop.