After several practice itterations using an assembly consisting of 2-1"x0.25"x460mm bars sandwiching a strip of 0.040x1"x460mm I was finally able to drive all 12 rivets within minimum specs. The bars and strip were clecoed together at the beginning and clamped into the jig shown in Fig. 3.
Fig. 1 shows typical shop heads after riveting. Fig. 2 shows typical driven heads after riveting and the homemade go-no go rivet gage that I made to check the driven heads. The gage is made of a piece of .025x18mmx60mm 6061-T6. The small notch is 5/64" deep and 1/4" wide to verify that the driven head has at least minimum thickness. The min allowable thickness is given as 0.075"~=5/64" by MIL-R-47196A. The max allowable diameter is given as 11/32" Std. Aircraft Handbook, 6th Ed. The minimum allowable diameter is given as 0.075"~=5/64" by MIL-R-47196A.
Lessons learned, in no particular order:
1. I am unable to hold the rivet gun steady enough with one hand, so I need help to buck the rivets.
2. It seems to work best to view the rivet set from above, and then to hold the rivet gun so that the edge of the set appears to be parallel to the base metal.
3. The assembly to be riveted must be held as nearly motionless as possible by the jig. An earlier jig clamped the bars to 2-2x4's that were screwed to the sides of a 2x6. I believe that the jig rotated under the impact such that the set drifted to the bottom of the assembly with mangled shop heads as the result. The jig shown in Fig. 3 worked very well.
4. The rivet gage (Fig. 2) is very important. I was trying to achieve driven heads that were way thicker and shorter than required. By using the gage and only driving the rivets to just pass the minimum diameter spec, I could reduce drive times significantly, which reduced the damage to the shop heads.
5. With the nice clean shop heads (Fig. 1) I found that the rivet removal drill guide that I bought from Brown Tool (P/N 154) I could reliably drill the center of the rivets. The drill guide worked very well. A ver
