Let The Fun Begain, New build on the Table.

[Ross77]

Just thought I'd better check but the 125mm was only an example, actual value will depend of your router collet and cutter length.

What router/spindle are you using? can it be fixed at the top as well? as the L shaped mount is also a bit weak.

[Bush Flyer]

I have now reinforced the L shaped mount. Its now braced right to the top now.
The router that I will be using is the Kress 530 with a 3.175mm and a 6.35mm collets and I was going to get the mount from CNC4YOU.
Here is the latest drawing of the Z axis.

[Bush Flyer]

Here are the final drawings

[Robin Hewitt]

Here are the final drawings

No they are not at all final, they're still crap

Look at the distance from the tool tip to the bearings above. 3 miles is too much.

Find a good solid cardboard box. Remove front and back. Try standing something on top.

When you figure out how to stop it collapsing, go back to your router drawing and try again.

[Ross77]

No they are not at all final, they're still crap

Harsh but fair eh Robin.

I would agree that the gantry sides are way to slender. You either need to reduce the height of the y axis or thicken up the side plates with some of that profile section. Having now seen the whole design I would reiterate my earlier comment about increasing the distance between the y axiz rails as that will reduce the torsional force on the gantry sides and also give a better ratio of supported to unsupported plate (not sure if that's the best way to describe it?)

The Z axis is way to complicated , get rid of all the blocks and wedging plates. i.e. make the bottom plate as one piece that bolts to the bearing and is also the spindle mount. Do the same with the top plate and make it bolt to the bearing and be the ball screw mount. this will make it lighter, stronger and much easier to build.

Keep at it, as its worth getting right before you start building.

[Bush Flyer]

OK I give up and have deleted all drawings to start again, But before I start with a new drawing please can you send a quick sketch of your cnc or a picture as I did not under stand what you mean about the bottom plate as one piece that bolts to the bearing and is also the spindle mount, Remember I have no machining ability so I will be buying the aluminium cut from the supplier at 20mm thick and cut to size as I am disabled and could not hacksaw 20mm thick aluminium plate. But I do have a drill press. I Have been copying some designs but have been adding some extra bracing etc. So now I have a blank screen on my computer and before I start again it would be nice to see your CNC or where to find your build to give me some help in the design.

[Robin Hewitt]

OK I give up and have deleted all drawings to start again

Oops, lets not over-react, don't empty that recycle bin quite yet. But you are making a newbie mistake

There is no set way of doing this, best way depends on what you have to work with and what you are trying to achieve.

The newbie mistake is guessing that at some nebulous time in the future you will want the gantry to clear 6".

In the real world you do 99% of your cutting in the bottom 1" because that is the length of your average router bit.

Get it wrong and 99% of your cutting is done at full tool extension and the machine tries to shake itself to bits.

Q1: What height does your gantry need to clear?