Posted on September 9, 2009
Hello again folks! The front end of the GRV-2 is showing signs of progress. I had just finished building the disc hub and was poised to mount it to the Douglas wheel. The 1/4” holes that were pre-drilled into the disc hub will now serve as drill guides for the six 1/4-20 threaded holes to be made in the wheel hub. The disc hub has a hub collar cut into the back side which will greatly help center the disc hub on the wheel hub. This feature should make the alignment of the two as near as perfect as possible.
I used a 1/4” bit to “mark” the centers of two opposing mounting holes in the disc hub and then used a smaller drill bit to make holes for the 1/4-20 tap. Once the two holes were tapped I installed two 1/4-20 x 1-1/2” alloy steel cap screws to hold the hub in place. I could now drill the centering holes in all of the remaining hub screw holes.