Quote Originally Posted by CaptainBarnacles View Post
Cheers for that Jazz

It's stuff like this where years of experience really show. It all looked good (to me) on my plan but the practicalities such as being able to access screws or adjust alignment etc just don't become apparent (again, to me) on a model. I would have been stuck into the build before having one of those "d'oh!" moments.
One trick I used was once I had the design all sorted, I put it to one side and started the assembly from scratch, bringing in each component at a time and working out how to attach it, and zooming out to see what access I'd have at each stage.

Still doesn't totally work - but it helps a lot. There are still two bolts that I have no idea how to access under the gantry!

I wouldn't wait too long before adding bolts into your model - the heads can be large enough to change things, and then you might want to think about countersinking them. This ties in with the adjustment Jazz is referring to; there might be places like the Y axis ballnut connection where you want a bit more adjustment room. For example, here I used slots so I didn't have to be spot on on the height of the screw vs the rails. How would you adjust each connection in all three axis? How will you tighten the motor belts? etc.

It was all very overwhelming at the start, but now I'm looking back I regret not going that extra mile with the CAD and thinking of ingenious limit switch placements to hide them away from everything. Its a little irritating trying to retrofit them now. Obviously that's not a concern for right now, but I'd at least consider it before starting the build. The same goes for covering the screws and rails somehow - I'd prefer my build if they were protected from chips, and lubrication pipes to make everything easy to lube when its in place.