Steel frame cnc router design/build

[CraftyGeek]

Chaps - i'm dithering about with the gantry quite a bit...can't come up with an approach that i'm happy with yet.

I've been looking around at a lot of build threads on here & cnczone...I haven't seen a gantry design that seems to suit what i'm doing.

Firstly - do I need to be concerned about weight. ie, am I ok using steel box or is this something that I may regret later?

Secondly - Jazz, the mock up design that you posted earlier in this thread - the gantry on that has 2 lengths of steel box attaching to vertical end pieces. I assume this would have to be a weld - my concern here is alignment & the lack of adjustment. Is there another way of going about it?

I'm trying to keep the range of materials that need to be purchased down...i've been looking at using aluminium box with a vertical plate - but it starts upping the budget quite quickly.

I'll also drop in a note here that I also really like the simplicity of KingCreaky's gantry...cheaper than some options, but the ally rect box & front plate add up quite quickly.

Any thoughts?

[kingcreaky]

Chaps - i'm dithering about with the gantry quite a bit...can't come up with an approach that i'm happy with yet.

chaps, im going to stick my neck out here, and before I even say anything Ive only made one machine... but what I do have in common with CraftyGeek is I am also DIY, so this was my gantry approach, slate it if you will, its not perfect but it was all done by hand with pillar drill hand punch and ruler.

[JAZZCNC]

Firstly - do I need to be concerned about weight. ie, am I ok using steel box or is this something that I may regret later?

No but within reason, weight is your friend when cutting has it allows deeper depths of cut, obviously there's a limit and it affects other areas of machine like motors, drives, screws etc if you go too heavy. Stay within 80Kg and you'll be ok with steppers.!!. . . Heavier than this and you'll be into servo territory.

Secondly - Jazz, the mock up design that you posted earlier in this thread - the gantry on that has 2 lengths of steel box attaching to vertical end pieces. I assume this would have to be a weld - my concern here is alignment & the lack of adjustment. Is there another way of going about it?

Doesn't really matter because all the adjustment is taken care of thru the rail mounting and were gantry sits on X axis bearings. . . The only requirement is that it's not twisted.

There are several ways to do different and I just drew this quickly to give an idea of easy and strong which go with single screw.
Really how you go about it depends on the job in hand, like in creakys case it was simple but would only really be suitable or woodwork type cutting any harder material like aluminium or if higher accuracy say for fine engraving, by that I mean in brass or Aluminium, PCB's etc where required then this is when weaknesses show thru quickly. . . . Resonance and vibration being the enemy has hollow aluminium box isn't stiff enough.! . . . It's also only works with twin screws and with single screw wouldn't be very good at all.!!

Your problem or complexity/weakness comes from using single screw.!!

[JoeHarris]

Your problem or complexity/weakness comes from using single screw.!!

Get onto old Chai he'll sort you out with an extra screw for a bargain price and you won't look back!