Wednesday, June 13, 2012

R&D Delays Finally Resolved

Yet another delay was encountered last week. Decided it prudent to test the standard 120 degree dimple die set that will be used with the C-frame my friend Pete (owner of the RV-9A I helped build) loaned me for the project.
                                              120 degree dimple die set that was discovered to be slightly off.
                                              C-frame with dimple dies installed. The plunger is pulled down
                                              until the centering pin on the male die goes through the hole in the
                                              material to be dimpled. Next the plunger is whacked with a mallet
                                              to make a dimple in the material.

There was some scrap metal available that was removed from the vertical stabilizer ribs so decided to test the 120 degree dimple dies with the C-frame. Much to my surprise, the dimples were not deep enough and the rivets were standing a little proud … not good! I’m not going to mention the manufacturer of the dies because all the other dies and tools purchased from them are of good quality and appear to be fine so this must be an anomaly, although I will try to get credit for the dies.

Based on the perfect dimples the custom made Avery dimple dies made, DOG Aviation’s procurement department placed a rush order for the Avery version of the standard 120 degree dimple dies. They just came in today and were immediately tested in the C-frame. Results … perfect dimples.
                                         One can clearly see the rivet on the right is sitting proud and not flush.

Clicking on the photo to enlarge it will show the rivet on the left is setting in the dimple made by the new Avery 120 degree dimple die set. Perfect ... not at all proud. The rivet on the right is setting in the dimple made with the problem dimple die set.  Is it really that big of a deal? Probably not, but quality control is the responsibility of the builder. A flush rivet is called a flush rivet for a reason … it is supposed to set flush.

Builder Tip:
If it does not look right, then most likely it is not right. Examine parts and workmanship closely. The photo above is a clear example of the need to keep a keen eye on the way parts fit together.

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