I have a 2013 DK40 that has already suffered a few blows to the lower grill in the woods. Don't really like the idea of adding expanded metal to the factory GG due to lack of coverage of the factory GG down low. So decided to build a GG with better coverage.
I could try and describe it but will just post some photos instead.
Yes the bottom bracket started out as a C-channel.
This C-channel is a little odd compared to what is available in the USA.
It is a piece of Metric Channel that was used as a crate for large Japanese CNC machines.
It measures 3"x6" with a center of the web thickness of .350"
The metal was just slightly to small for the Kioti GG/weight rack bolt pattern. I had to mill reliefs where the bolts meet the contours of the metal. And yes the bottom angle was milled off.
The rest of the grocery list.
all square tube is 3/16" and all rectangle is 1/8"
-2x2" square
-1.5x1.5" square
-1x2" rectangle (technically 11gauge .120")
-1.5"x1/2"x1/8" c-channel for grill
-3x3"x3/8" angle
-The bottom inner bolt mounts on the GG are modified 2"x2"x1/4" square with one of the sided cut out of the square.
-5/16-18x3/4" SS button screws with HD SS washers, all 18-8 grade.
-1/2"-13x1" grade 8 HHCS LE stamped (Lake Erie made in Indiana)
-M14 grade 10.9 flat washers.
-factory M14x1.5x40mm grade 9 HHCS
All welded with .035" MIG wire. Millermatic 212.
All bolts Blue locktited.