1200mmX900mmX170mm 4axis cnc

[routercnc]

Advice needed.

I repost here since at my other thread I didn't get any respond.
I am thinking for something like that for my X axis, I prefer to build it bolt on ,with minimum welding, since it is one man job and better to handle, plus I want to avoid metal stress,that I am going to get with welding.
X axis is made from 90x90x900x4mm steel structural sections
At front and back of the steel tubes I will place two steel plates 5mm to stiffness the structure ,also the two plates ,left and right, are going to be 5 -7 mom.

With 2 off 90x90 sections stacked on top of each other with what looks like another 90 mm gap the gantry is going to be very tall. This means the loads going into the top rail are along way from the X axis ballscrews (which react that load) and you are reliant on the sheet panel sides to do the load transfer.

Is this height because you need lots of Z travel?

Whilst yes this would work, I think there are more elegant steel fabricated solutions. For example this one from 'Toomast':


There's this one too:

Both involve welding so as you point out care is required during construction.

More popular is aluminium extrusion for the gantry because it is easier to work with:


For wood working, guitar making and occasional aluminium I would say all the above are suitable designs.

[Nickhofen]

Is this height because you need lots of Z travel?.

Sorry I forgot to mention that the total height is 180mm.
I have read at another thread here , that to eliminate the forces when Z axis is cutting, the carriege must be at least at 250 mm from their outer sides.

[Nickhofen]

Sorry I forgot to mention that the total height is 280mm.
I have read at another thread here , that to eliminate the forces when Z axis is cutting, the carriege must be at least at 250 mm from their outer sides.

I fount another thread "http://www.mycncuk.com/threads/8975-Linear-rail-question?p=88244#post88244", one that you have start Robert (Nr1madman), where Jazzcnc states that 160mm for Y axis height is good enough!
Time to redesign !

[Nr1madman]

I fount another thread "http://www.mycncuk.com/threads/8975-Linear-rail-question?p=88244#post88244", one that you have start Robert (Nr1madman), where Jazzcnc states that 160mm for Y axis height is good enough!
Time to redesign !

Hohoho you know the phrase "seek and you shall find". Well done ;)

But if I remember correctly my choice was 80x160 profile for gantry but jazz and Boyan stated that 2pcs of 80x40 is plenty enough in L formation. That gives the gantry a hight of 120mm!

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[Clive S]

Hohoho you know the phrase "seek and you shall find". Well done ;)

But if I remember correctly my choice was 80x160 profile for gantry but jazz and Boyan stated that 2pcs of 80x40 is plenty enough in L formation. That gives the gantry a hight of 120mm!

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I think I have seen Jazz use 90 by 45 as that is the correct spacing for 20mm rails in profile

[Nickhofen]

I think I have seen Jazz use 90 by 45 as that is the correct spacing for 20mm rails in profile

90x45 each tube Clive? And what spacing between for the screw can we say that is ideal?

[Clive S]

90x45 each tube Clive? And what spacing between for the screw can we say that is ideal?

Not sure what you mean by this the two profile are fitted together to make an L so the lower one is horizontal with the other one sitting on top vertical, the BK and BF bearings for the screw will fit the slots in the profile