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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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.

Hahaha , Good idea thankyou

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Aluminium Profile www.easaluminium.eu

Hijackin´ ye ole thread ......

Is there a way to directly join t-slot extrusions back on back?

I would like to connect two or more 15180 plates together to make something like 15360....cheap router main plate.
off course I could fix it with some perpendicular bars holding them together, but I would love to do it back to back without anything sticking out of any side

Thank you!

Sure- use short button head cap screws and t-nuts. You'll have to drill a hole for tool access at each screw.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Quote
Lee ***
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

Try here
[us.misumi-ec.com]

Quote
Ed3D
@ 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

Very little chance it will happen, for many reasons ; steel has less friction against aluminium than aluminium against aluminium ; surfaces are orders of magnitude away (but Amonton second law explains it has no influence...). The axial force is way higher than rotational force and friction force is proportional to pressure. Only a few threads are in contact with each others, forces are applied in such a way than torque become negligible etc.

At worst, a very simple trick I was taught decades ago : if you don't want two surfaces to slip, just apply something that will prevent this to happen ! An old mechanic trick is to apply some abarsive between the two surfaces. Chalk is (was) very common for conical junctions (like flywheel/crankshaft : but don't do it, it makes it extremely difficult to take apart later !!! Could also be some grinding paste, like valve (fine) grinding paste, or some emery, or even a "gasket" made of sand paper. Sand paper is a well known trick of the trade that machinists have been using for ages when tightening parts of slighly dissimilar widths in a milling machine vice, for gang machining. Just some very fine sand mixed with some grease is enough to prevent any rotation (rotation that will never happen while tightening blind joints ; if it happens, it's because you didn't properly use the tap, or the tap is just an out of specs crap ; or the screws are themselves out of specs, or the ends are not flat...). Few people konw it : when torqing king a bolt (using a torque wrench), threads and screw head (or nut) have to be lubricated.

Blind joints : maximize friction between the parts, and minimize friction between the threads, and between the screw head and the part. And that's it !

I'm sure some abrasive toothpaste is more than enough ! (Pepsodent or Ultrabrite for example)

Was thinking of this thread today, while assembling a frame on a metrology surface plate. Did it several times, attempting to make the parts rotating and slipping... The surface plate makes it easy to see if there's any movement between the parts No way ! Was unable to make anything rotate (while using Grower washers under the CHC screw heads, without lubricating threads and not using abrasive between the extrusions).

Edited 2 time(s). Last edit at 01/11/2023 06:10PM by yet-another-average-joe.