Connecting extruded aluminium?

End Fastener for 20mm Aluminum Extrusion

I have a welded iron cuboid that I got off as scrap from a local hardware store....they used it like a table(unable to post photos)...it's not very big but quite decent in size.but i guess I can get at least 35x35x35 volume out of it.....it does not wobble...
However I am concerned that how will I be able to align my mechanism accordingly.

My ideas.....shall I mill a metal plate for fixing a corexy mechanism (stacked belt) and attach it to the top and have the build plate on z axis (I guess I will use smooth rods for that to save money to buy profile guides for the xy movement and also to the fact that the cuboid does not have support shafts on sides)

Please enlighten me on how to use it perfectly.....I am really impressed by its rigidity and does not wish to let it go waste.

Quote
sudarshan
I have a welded iron cuboid that I got off as scrap from a local hardware store....they used it like a table(unable to post photos)...it's not very big but quite decent in size.but i guess I can get at least 35x35x35 volume out of it.....it does not wobble...
However I am concerned that how will I be able to align my mechanism accordingly.

My ideas.....shall I mill a metal plate for fixing a corexy mechanism (stacked belt) and attach it to the top and have the build plate on z axis (I guess I will use smooth rods for that to save money to buy profile guides for the xy movement and also to the fact that the cuboid does not have support shafts on sides)

Please enlighten me on how to use it perfectly.....I am really impressed by its rigidity and does not wish to let it go waste.

[reprap.org]

minimum triple lead screws, minimum dual rails (or rods) for z and you'll do fine. a metal plate sounds awesome and a lot less hassle, just make absolutely sure that the alignments are good. when you get extrusion cut to length you can at least adjust it slightly through the fixings: in this case you don't have that option, and the cube is highly unlikely to be true-to-square. so you'll need to take that into account when attaching the plate and the z mechanism.

also i heard that aluminium and steel do not mix: some sort of chemical reaction that oxidises the aluminium extremely rapidly: a problem i learned of from a mechanic who was restoring an astom martin DB5. something you should research carefully.

I would like to order 500mm of the following extrusion manufactured by MiSUMi Japan.

EFS6-30300

[uk.misumi-ec.com]

MiSUMi will not sell this extrusion in the USA. I need a supplier that can ship it to me in the U.S.A.

If anyone knows of a supplier that can process this order for me it would be appreciated.

Thanks.

slf

@ the_digital_dentist

How are you preventing rotation of the extrusion as you tighten the bolt using the method you show on the first page

Rotation is prevented by the force of the bolt. Friction in other words.
You can use milled brackets to ensure no movement, along with the digital dentist’s method.

I think you misunderstand. I make this blind joints quite often at work because of how rigid they are over the corner pieces but my issue that I seem to often have is that when the bolt is tight it prevents twisting but when you are in the process of tightening it it quite often causes the extrusion to rotate causing it to be fixed at the wrong orientation.

Edited 1 time(s). Last edit at 12/29/2018 06:17AM by Ed3D.

I just hold them down on a flat surface. I suppose you could temporarily bolt them to a flat plate before tightening the end screws if you were worried about perfect alignment.

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Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Same.
Milled brackets/plates do a similar job, but if you have a flat surface as described above, it would be easier. (Note: first connect the extrusions with the bracket, preferably on a flat surface. Then bolt the extrusions together.)

I might try laser cutting some acrylic corner brackets to hold them in place when tightening or even machining up a jig for it. I find even putting them on a flat surface they still kick up a bit but that may be because I’m using 5050 extrusion with self tapping trilobe screws that I find tend to jam and require a lot more torque.