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

[JAZZCNC]

If you do add one it needn't be thick - 10mm would be fine as it's only to stop the joint between the plates that the Y and Z bearing blocks mount on bending.

Know this is a bit late 3 weeks after posting but I've been asked for some input by Adil and was looking over the build again and spotted this comment.!!

Jonathan never have understood why you use this rear plate in the way you do because that rear plate on the back add's very little protection against the joint between Y axis bearing plate and Z axis rear plate bending in the vertical.?
The only forces that apply here are vertical force applied from one side and the overhang distance from the Y axis bearing plate to Z axis rear plate is nothing.? possibly few MM's. So the chances of that joint bending are zilch and if the forces were great enough to bend that then the rest of the frame and gantry are in big trouble and 99% sure something else would be bending/breaking much sooner.
Your design is an open ended box with very little strength in the vertical direction and if enough vertical force is applied at one side the other side will deflect in a similar manner.!

If you want to brace for that movement then plates on the side bolted into both plates would be much better and could be much thinner and still give far better bracing support than those backplates.? This back plate just add's weight and cost IMO for not enough gain and isn't required.!

[Iwant1]

So, while away all the bits and pieces I ordered arrived behind me. It was like Christmas, opening all the parcels. I loved it.

Here are some pictures which I think will help others new cnc builders realise how many parts we need to buy.

The first picture is my control box layout inside of an old pc case. 12v, 24v and 70v psu are here along with drives, safety relays, discharge resister, BOB and fuse box.


My spindle and VFD were from Chai, unfortunately FedEX hit me with a 35 quid bill. I bought an er20 collet set, and full cooling setup consisting of double ali radiator, 2 fans, and a pump with reservoir. Just need to buy hoses and adapters. It was a great feeling powering the spindle for the first time.


This picture shows all the other components like switches, connectors, wiring, e-stops and lever connector blocks. Just forgot to put the cy screened cable in this photo.


Close up of switches and plugs. Andy, here you can see the difference in size between my 3 homing switches and 6 regular micro limit switches. The green push button is for the safety reset and round toggle switch is a limits bypass. The ones in the middle seemed a bit small so I bought larger ones which can be seen on the top left of the pic.


Adil

[WandrinAndy]

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

[Iwant1]

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.

[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? I like how compact this is but does it come at a price?

[Jonathan]

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?

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.

[Iwant1]

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.

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.

[JoeHarris]

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?!

[JoeHarris]

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?!

[Iwant1]

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.