emily, blinkenlight witch
ChonkNC build progress: did some more fabrication. Planning to bolt the gantry legs to the base, but undecided how to attach the gantry to the legs; I'd like to be able to shim it for leveling (which suggests "not welding") but there's no obvious place to put bolts up there.

#theWorkshop #cncmachining
Feb 26 at 6:40amWeb
Show threadY⃒̸̷̝̜̙ͥͥͥngmarFeb 26
@emily Could weld some studs (threaded rod) on?
Show threademily, blinkenlight witchFeb 26
@yngmar Problem is the legs are vertical tubes, and the gantry sits on top of them, so there's nowhere to put a hole for the stud to go through because there is already a bigger hole there.

Might just cut some squares to weld over the tops, then studs coming out of the center of those.
Show threadY⃒̸̷̝̜̙ͥͥͥngmarFeb 26

@emily Oh, then you could go with that or tangs welded on. Or a flat bar welded to the legs to close them and double as tangs. That would increase stability too.

Tangs because then the bolts can be accessed better than with end plates.

Show threademily, blinkenlight witchFeb 26
@yngmar what do you mean by tangs?
Show threadY⃒̸̷̝̜̙ͥͥͥngmarFeb 26

@emily I mean like this. Strongest if you use a continous plate, assuming its going on the triangular part.

I might not have understood how it's supposed to go together :)

Show threadPalmAndNeedleFeb 26

@emily I would also go with externally welded on tabs and threaded rod. Just would like to add that standard threads have a lot radial and axial clearance in the mechanism and therefore make for poor alignment features.

But also: welded 50mm square steel tube? For a bench top mill?  you could build a gantry 5 times the span and height with that stuff. Why so overly chonk? What's wrong with aluminum extrusion and bolts?

Show threademily, blinkenlight witchFeb 26
@PalmAndNeedle more rigidity more better

and also I have a local supplier that sells their remnants to me cheap, this is ~$100 of steel
Show threademily, blinkenlight witchFeb 26
@PalmAndNeedle (I have built, slowly upgraded, and later disassembled an aluminum extrusion machine before, about half this size. A lot of the parts that are going on this frame were originally on that one. This is kinda a "what if I do that again, but overkill?" project.)
Show threadPalmAndNeedleFeb 26
@emily That makes one and a half more than I've built. And yeah, use what you have. I just can't help my engineering brain. Seeing overdimensioned heavy structural builds always makes my spidy senses tingle