This is the rock upon which I shall build...

https://www.flickr.com/photos/27748767@ ... ed-public/

When I saw that setting on the Reuseum floor all thoughts of using 4040 extrusion massively braced with corner plates and angle brackets flew right out of my head. Cost? $10.00

Sliding action will be provided by a THK HSR30 rail for the bed and a THK HSR25 rail across the gantry. I already had four 85 oz/in motors so I got Sintron to delete 4 of the motors from their electronics kit, taking the price down to $159. Despite being pictured with a MK2B bed the kit shipped with an MK3, but no LEDs soldered on it. No assembly instructions either.
So now I have a box of parts and a frame and have begun machining work on the frame for mounting the rails. I plan on using ball screws to move everything, with belt reduction drive to the screws unless I get some pretty fine pitch ones.

I want this printer so tough I can fricking lean on it without anything flexing. Might make a quick change mount to swap hot end and a high speed milling/engraving spindle. It shall laugh at hot cars... Saw that post on here. Ouch. Could print Salvador Dali inspired designs.

Machine work is no problem. I have metal lathes (only 5 of them...) a PLM2000 CNC mill, an Emco knee mill that's pretty much exactly like a Grizzly G0731 and various other fun tools accumulated by my 76 year old father and 44 year old me over many years. One lathe, a 13" LeBlond "trainer" (lighter weight 'Roundhead' model from 1943) is in process of being fixed. The rest are operational. The other big machine is a 1990 Acra CNC knee mill with a 10x50" table, in process of a total electronics upgrade. It's currently stalled due to the 13" lathe being in the way.

After I get the mechanicals built, I'll likely need some help getting the firmware etc sorted so it'll be a 3D printer instead of just an assemblage of parts. Already have a Core 2 Quad computer built for slicing and dicing 3D and running the printer etc. Got a super deal on it, $0. Also $0 for the CPU which came in an otherwise defekt PC. The good box happened to be the variant of Dell Inspiron 530 that *is not* limited to dual core and only 4 gig RAM.

Welcome to the forum! We can definitely help on the firmware front. Several of us have built our own 3D printers.

What print volume are you targeting?

Randy

Print volume, size of the MK3 heated bed by tall enough. The side posts are 24" above the top of the square frame at the bottom, so minus some for the fixed crossbar and the Z axis gantry, and however far the hot end projects below that, and however high up the bed will be. Between the posts is 11.25"

So height will be whatever space is left after mounting everything.

I haven't checked the bed for flatness. Are they usually pretty flat or do they need to be pressed under glass? I'm thinking of a metal vacuum platform to suck it down, like a vacuum forming table.

Got any sources for affordable ball screws? I'm leaning towards having them under tension with angular contact ball bearings at each end. I've read that a tensioned screw can be run up to 2x faster, or a smaller screw can be run as fast as a heavier, untensioned one. Normally not a need for real high speed in 3D printing, but time can be saved on rapid moves when not printing. I have some ideas for printing multiple copies or things.

I'm converting a JET 9x20 lathe to CNC and for the cross slide there's only room for a 5/16" ball screw. Definitely going to be putting a little 'stretch' on it to avoid having it flex. I was wanting to get a Denford ORAC lathe but after finding a site showing a complete teardown - those lathes are a Compact 8 clone and I can make the cross slide have more usable travel than what Denford did, and they only used an 8mm diameter screw, untensioned.

I might get over there Tuesday. I need a power supply for my printer. I know Reuseum has a large assortment. What voltage and amps should I look for? Four of the motors I have are rated at 6 volt, 1.2 amp. The fifth, for the extruder, is whatever Sintron sells with their kits. Then there's the Arduino + RAMPS and the MK3 heatbed. Ideally I'd like to use just one supply to power everything.

thanks for this informatioin.