My baby 15" x 15" machine

[wilfy]

brilliant thanks for the reply... is there anything else that looks out?? i did wonder if the gantry would need any triangle/cross bracing from top to bottom outer corner?

what i might do to start with is use one screw and then if i find myself cutting or want to start cutting metal on a regular basis i'll upgrade to a second screw.

the chances are if i get the bug i think i'm going to get from this machine i'll end up re-building and making a bigger machine anyway as i originally wanted a 4'x4' machine but cant justify the cost until i can get this machine to prove itself.

thanks again for the input i'll work on locating motors, mounting plates and anything else thats missing, i can also start to work out screw sizes so that i can get a price for my missus from chai

[Jonathan]

I forgot to answer the motor question...

You could use less than 3Nm motors in places without reducing the performance, but 3Nm motors are by far the best price per Nm so it's hardly worth getting anything smaller, especially since the 3Nm motors would be good for the 4'x4' machine if you decide to make it. Currently the cheapest place I know of to get them is here:

Nema23 3.1Nm

Remember to ask Chai to make the end portion of the screw longer (25mm is good) to make it easier to fit and align the pulleys. This will of course mean adding a little to the length of the screws you buy.

The gantry is currently quite tall so it look like it could bend 'backwards' (parallel to X) relatively easily. It would be a good idea to add in some diagonal pieces as you said to combat that.