The first picture shows the end of a bolt, 6 or 8 inch, if I remember right. I cut the head off it and it fit right into the gear tubing after cleaning out the tubing galling from the weld up. The second picture shows the 'pinning' bolt, AN3 that was in place as a result of drilling a hole through the gear tubing AND the bolt to hold it in place. This worked well for me... the bolt was a 5/8 high tension steel bolt. I stayed away from a Grade 8 bolt assuming it may be a bit brittle for landing gear operations. This may or may not be a good assumption. This has worked well for me and easily replaced if 'something' changes the straightness of the 'axle' bolt. Hope this helps.
HughS.
NightEagle