RGS #20

Been awhile since I have been able to work on #20, but can report some progress. I have been working my way from the frame through the tumbling shaft and rocker, with the next step being the links. Chris Z. inspected the links and we found the left rear half was cracked too badly to repair. I measured all the link halves and found that three out of four had their arc radius within a half inch, which isn't too bad for about a three foot radius. The forth link was off by about an inch and a half. Naturally, the cracked link was one of the three matching ones. So typical.

We sent the right link halves to be re-case hardened to a depth of no less than 1/16" in order to ensure not grinding through the case. The following pictures show the grinding progression through the initial assembly which I completed this afternoon. Hope to grind the end blocks and make the shims this weekend.

The final picture shows the links temporarily assembled for the first time to check that their arc centers coincide and the spacing is equal end to end. Arcs were determined based on the bolt pitch of the span bar having the link hanger pin. Hope to maintain 0.005" tolerance end to end. No secret why they went to one piece links.


Photo shows laser used to measure and set up the links.