Table of Contents
Two lengths of 20x20mm aluminum extrusion were provided in the 2014 kit of parts. Also included were some thread-rolling screws for use with the extrusion. Catalog page: http://www13.boschrexroth-us.com/Framing_Shop/pdf/101/Page%202-11.pdf
Parts given as part of KOP 2014:
- 3842992888 - two pieces. 20x20mm profile, 1.5m long http://www13.boschrexroth-us.com/Framing_Shop/Product/View_Product.aspx?category=10101&subcategory=1
- 3842528593 - S6x16 self-tapping connection screw, T25 Torx head
the self-tappng screws are used to make a fixed right-angle joint, as shown in the picture on this page: http://www13.boschrexroth-us.com/Framing_Shop/pdf/102/Page%203-17.pdf
Additional material purchased
- 3842517173 - more of the same 20×20 aluminum extrusion, with unfinished ends. 3m long.
- 3842528593 - more of the same self-tapping screws
- 3842523511 - gusset for adjustable right-angle joint without drilling. with hardware:
the gussets are shown here: http://www13.boschrexroth-us.com/Framing_Shop/pdf/102/Page%203-4.pdf and here: http://www13.boschrexroth-us.com/Framing_Shop/Product/View_Product.aspx?category=10201&subcategory=1
Other Compatible Extrusion
Lots of places have compatible 20x20mm extrusion.
- “8020” brand
- https://www.adafruit.com/category/122 - we bought some bolts and t-nuts here
Summary
there are two ways to join this aluminum. drill and use the self-tapping screws in the corners of frames (fixed structure and catapult). use the gussets if the position may need to be adjusted. Use both if a corner needs to be especially strong.