For the frame construction,

For the frame construction, is there any reason why not to use a regular Home Depot 90 degrees bracket instead of the expensive special T-Slot brackets? I can buy a whole box of these for a few bucks.
http://www.homedepot.com/catalog/productImages/400/a0/a039eeec-2e67-42b0-99e7-a1e16f42fcc9_400.jpg

if you use t slot, brackets aren’t needed

Angle brackets can easily flex at the angle of inflection - not so much as to cause them to fail at holding up a shelf, but enough to distort the extruder’s alignment in a 3D Printer.

Gotcha

@D_Rob Can you explain? In all the diagram and pictures I’ve seen, everyone seems to use brackets.

@Shachar_Weis cross drilled hole and a 5mm button head screw can do the trick. Look back through D Robs YouTube videos. He explained it in one of his assembly videos.

Tap the end holes in the extrusion. put a 1/4-20 or 5mm button head screw in it. Watch @Thomas_Sanladerer outlaw tapping video. The head fits the t slot like a t nut. All you need are holes through the t slot for the allen wrench to secure. It’s tighter than Dick’s hatband. my vid does show an assembly method that make all cuts, but the vertical extrusion a whole lot less critical.

here is the link to said video in case anyone else is curious. https://plus.google.com/u/0/108729945898131117315/videos?pid=5989375241070804258&oid=108729945898131117315

I ended printing some 100mm x 100mm corner brackets that work way better than those little corner ones you can buy. This is one of the corners that incorporated a filament holder into. The other corners just have a 45 deg brace. I can send if anybody would like. https://www.facebook.com/my3dph/photos/pb.595124113871348.-2207520000.1415489025./774121785971579/?type=3&src=https%3A%2F%2Fscontent-a-sea.xx.fbcdn.net%2Fhphotos-xap1%2Fv%2Ft1.0-9%2F10455188_774121785971579_3448500890548846248_n.jpg%3Foh%3D7ba9ae6a6a0b5ddb0a07ccd71f289282%26oe%3D54D28993&size=960%2C720&fbid=774121785971579

I work a bit with extrusion. Tapping the end is a mugs game :slight_smile:

For joining extrusion I use self-tapping hex-head screws, like these: http://www.aliexpress.com/item/Grade-8-8-HEX-socket-Head-self-tapping-Screws-M5-30mm-50pcs-for-MODEL-SPEAKERS/831267061.html

You just drill the end to ease the way - for M5 screws I drill a 4mm hole (always use lube for drilling and screwing, my Dad says! :wink:

For mounting 10mm or 8mm or 6mm smooth shafts, I use these: http://www.aliexpress.com/item/8-mm-bearing-kirksite-bearing-insert-bearing-with-housing-KP08-pillow-block-bearing/1121096212.html

There are all manner of different sizes and they screw straight into t-slot nuts. You can swap out the bearings if you want - so you can fit any sized shaft you need.

As to corner brackets, I use two types with 2020 - the small 2020 sized ones like this: http://www.aliexpress.com/item/Corner-Brakets-Aluminum-color-powder-coated-used-for-profile-20-series/798082376.html

Or for making sure things are square, I use the larger 3060 brackets - they fit in the 2020 channel just fine and work well as feet.: http://www.aliexpress.com/item/3060-Aluminum-Profile-Corner-Fitting-Angle-30-60-Decorative-Brackets-Aluminum-Profile-Accessories-L-Connector/2032521626.html

They do project past the extrusion, so you need to think about where you will use them, but they are strong as heck and only 60c each.

I tend to buy stock - 50 or so at a go. And buy quality spring-loaded t-nuts, not those cheap but annoying hammer-head t-nuts that fall out or twist when you are trying to slide them into place. I always have a large selection of drop-in t-nuts as well. Nothing worse than having to pull your creation apart because you forgot to drop in a t-nut.

@Mike_Thornbury Awesome links, thanks ! Looks like this could save some time and money.

@Shachar_Weis If you are going to buy from Aliexpress, make sure you do so on or after the 11/11. There is a massive sale going on - you should be able to get about 15% off most things.

And if you haven’t dealt with Aliexpress before - be really careful about reading the small print - they aren’t dishonest, but sometimes details are lost in translation. And always negotiate.

How do you negotiate? Do you send messages to the vendors asking for a lower price ?

Best to install " Trade manager ". Can be downloaded from alibaba’s site.
Can send mes also. each item for sale has a ms link to the seller.