There are six F-1212 step ribs, three left and three right. The six F-1212 ribs required deburring and some dimpling. Per the plans, the two F-1212 ribs that will become the centermost two ribs receive 120 degree dimples along the entire top flange of both ribs … because they will become a portion the tunnel and a removable cover plate will sit on top of them. The bottom most rivet hole in the forward flanges of the outer most rib on each side also received a 120 degree dimple. In addition, all of the F-1212 L&R ribs received 120 degree dimples in all the rivet holes of the bottom flange to accommodate the flush rivets being used on the RV-12 project.
Using the Scotch-Brite wheel to remove burrs and
smooth edges on one of the six F-1212 step ribs.
Dimpling one of the F-1212 ribs with the pneumatic
Bottom flange of all F-1212-L&R ribs were dimpled
for flush rivets being used on the RV-12 project.
And now for the 30 mile dimples … overall the
DOG Aviation procurement department has done a great job amassing the necessary
tools and specialty items required to bring the RV-12 to fruition. One tool which
was overlooked was a set of #40 dimple dies for 3/32” rivets that are the type
with the holes in them used with a hand rivet puller … or the type that has the
dimple dies welded onto the end of a vice grip. The shop is outfitted nicely
with various dimple die sets for #30 rivets but only has one set for making #40
dimples using a typical rivet squeezer with a yoke.
As luck would have it, the W-1226-L&R floor
pans required quite a few dimples … however, there were two dimples on the front
edge for a nutplate that the tools in the shop just could not reach. The edge
on this piece of metal is bent way more than 90 degrees so there is not enough
clearance for the squeezer yoke to get low enough to allow the dimple die to
align with the hole.
This photo shows how the tight bend interferes
with the squeezer yoke preventing the dimple die from getting low enough.
Tom to the rescue …. I contacted a fellow RV
builder who is building a Van’s RV-10 (a beautiful four place aircraft). Tom
lives around 15 miles away and had two types of #40 dimple dies that would do
the job … so the two F-1226 floors were packed up and carted over to Tom’s
house and dimpled there. The tool that was used to make the dimples resembles a
vice grip which has a set of dimple dies welded onto the end of the jaws.
Fortunately, there was just enough room for the tool to fit and the rivet holes
for the nutplate on both floors were successfully dimpled. Sadly, I forgot to
take my camera to Tom’s so don’t have photos of the tool used to form the
dimples or of his project to share. Thanks Tom!!!.
Dimples in the F-1226-L&R floors made at Tom’s
house are circled in red.
The last item to be worked on before the next
primer session is the W-1202F bulkhead. The edges were deburred and Smoothed on
a Scotch-Brite wheel then the nutplate rivet holes on the top flange were dimpled.
In addition, the bottom flange and the side flanges were dimpled for the 120
degree flush rivets being used on the RV-12 project.
Making 120 degree dimples in the bottom flange of
the F-1202F bulkhead for flush rivets.
Pile of parts ready for cleaning, scuffing with
a Scotch-Brite pad and priming.