I've built this machine 100 different times in my head!!!

They've certainly helped me now view some terms as images... Thanks Adil.

Thought I'd put up my latest renderings of how I want my router built. I went with the L extrusion gantry design which came out on top in this thread, effect-forces-gantry-cross-sections.

A big thanks to Dean for helping me along the way, with which I'm now set on a final design. The drawing mostly concentrates on the gantry and z axis. The x axis is not to scale , just for visual purposes of how the components connect.

So, I've got most of the electronic bits, my profiled rails are on route, and the next thing on my order list is the extrusion. The ali plate order needs some jiggling as I want all small parts to fit on one large sheet, so its easier for machining.

The frame, not pictured here, is still made from welded and bolted steel box section.

The x axis drive will also be upgraded from 1 motor and a long belt, to 2 motors and 2 short belts, as my new drivers have stall detection. Will need to buy the extra motor and driver.

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I remember being advised that it was better to keep the ballscrew as close to the z axis as possible - between two ali extrusions rather than behind one...This is maybe not such an issue with profiled rail? I like how compact this is but does it come at a price?

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Originally Posted by JoeHarris

I remember being advised that it was better to keep the ballscrew as close to the z axis as possible - between two ali extrusions rather than behind one...This is maybe not such an issue with profiled rail?

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That's something I mention quite regularly. Profile rails will help to compensate for the ballscrew not being in the optimal location, which is directly between the rails on the gantry, but it will still be better if the ballscrew is closer. Currently the ballnuts seem to be 'out on a limb' which risks the plates they are mounted on bending which is best avoided.

I suppose when you go for the 'L' shape gantry, there isn't many options where the ballscrew can go. This type gantry was deemed stronger than having two separate extrusions top and bottom with the ballscrew inbetween. Some compromises have to be made, and I chose to go with a stronger gantry design.The statement below which JAZZCNC made form the 'effects gantry cross sections' thread reassured me it will be fine.

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Originally Posted by JAZZCNC

I've built machines using the green design and please believe me you have nothing to fear the strength is easily over the top for anything but steel or harder.

Yes it places the ball-screw slightly further back than what's considered ideal but again it's nothing and doesn't make any difference to how machine performs. The positive is the screw is away from the firing line and protected.

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Ok, just thought I'd flag it up. With a 20mm plate bolted to the back, two profiles on top of each other must be pretty strong though right?!

I have now read the thread cited above and the more I look at this L shaped gantry the more I like it! It's more compact, makes connection easier, its stronger laterally and omits the plate. Just one (maybe daft!) question. How do you join the two profiles?!

I've made a quick drawing of how I will be connecting them. A screw goes right through the bottom extrusions and screws up into a T-nut slotted in the top extrusion. The screw head will be sunk into the D slot for my profile rails to sit flat on the extrusion. Hope it clears it up a bit.

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Thanks, I figured that was how. Just wanted to check there wasn't some cunning way I hadn't thought of!

Think I'm going to be changing my design yet again!!