Steel frame cnc router design/build

[JAZZCNC]

Jazz my ex misses is on the prowl in wakefield tonight so bang one of your 16mm ballnuts in for me and tell her the backlash is way toooooo sloppy will ya

Listen mate been there done all that (well not done her. . Lol) Honestly she's not even worth the words your typing.!!

[Swarfing]

LOL! why do you think i left her for a CNC machine?

[GEOFFREY]

Tighter ballnuts and no backlash? G.

[Swarfing]

Thats the ticket Geoff

[JoeHarris]

Should have known.!! . . . Parcel tape and chewing gum. .

Haha cheers guys! Trade secrets eh?!

[CraftyGeek]

Ok - V2...

Inner end pieces are 15mm plate
Outer end plates are 20mm
bearing blocks also beefed to 20mm
Front plate is still 5mm - more to keep crap away from the leadscrew than perform a major structural role...although should help with twist & sideways flex.
Rear stell plate removed - although that was there more for a convenient flat mounting surface rather than anything majorly structural.

Still comes in under £100 - so that keeps me happy

[JAZZCNC]

Better but still no inner triangle brace.!! See pic of brace on my machine. It's only a small thing but does help stiffen and dampen vibration more than it looks.

Don't let Money run this Build too much because you could easily find you spoil it for not much more money.!! . . . Better waiting and saving up to do it right than skimp. It's a lot of work building a CNC machine and just small things that don't cost the earth can make a big difference.

[CraftyGeek]

There is one inner brace already - 15mm plate & then 20mm outer on the end.

I'll look at doubling up that inner brace later.

I have to keep an eye on the cost as its already adding up to way more than I originally intended...& its going to take me months & months to sort out the finances for it - so yes, the budget is important. I appreciate that its not worth cutting some corners - but I can't shove a bottomless pit of funds at it.

[JAZZCNC]

There is one inner brace already - 15mm plate & then 20mm outer on the end.

I'll look at doubling up that inner brace later.

Yep but the more towards the centre you can support it the better, bring that inner triangle inwards the gantry side does the same job so it's not needed there. On mine it's only built like that for ease of fitting it's piece on it's own that bolts on could have easily done it like suggested you do and would work just the same.

I have to keep an eye on the cost as its already adding up to way more than I originally intended...& its going to take me months & months to sort out the finances for it - so yes, the budget is important. I appreciate that its not worth cutting some corners - but I can't shove a bottomless pit of funds at it.

Yep completely agree and understand but just understand it's here at this point when building frame you can't afford to cut corners. If you have a weak structure you have a Weak machine and it will always be weak or hard to correct without major hassle and expense at later date.
I've seen this often where folks think I'll do it on cheap then upgrade later only to find out it's not that simple or easy and end up scrapping and starting again. . . . It's called learning the hard way, I'm just trying to help steer around that.!

[CraftyGeek]

Right, the gantry is moving along nicely - i'm at the stage now where i'm starting to add the Z-axis. Its probably time to finalize rail/leadscrew choices before I go much further.

My thoughts have been
X - SB20 rail with 2x 1605 screw
Y - SB20 rail with 1605 screw
Z - SB16 rail with 1605 screw

I've seen mentions of clearance issues/fiddlyness when using SB16 with, I assume 1605 screws...should I just use SB20 for Z as well?
All axis will have a single Nema 23 motor & be driven by belts/pinions. Initial power setup will only be 24V - but I plan on upgrading this to at least 48V in the relatively near future.

Does this sound ok?...what about the Z axis setup?