Chamfer fuel refill port mounting plate

A deburring tool was used to chamfer the inner edge of the inside mounting ring so as to permit the Andair port to sit flush.

Subsequently I realised that this was not the goal of this chamfering. The way I did it the fuel cap surface would lie flush not with the fuel tank skin, but about 0.6mm lower - flush with the WG-FLG-001-X-X-. Indeed I could get the fuel tank filler tap to lie flush with the skin if I did not chamfer at all. The problem with this is that the fuel filler cap sits only on a inside circular line-edge of FLG-002 and can in fact rock around a bit unless carefully jigged while the sealant is curing. A better idea is to take advantage of the chamfer I have already created, and remanufacture WG-FLG-001-X-X- not from 3.2mm 6061-T6 but 2.4mm. This will cause the filler cap to lie about 0.6mm proud of FLG-002 - in a well controlled orientation. Consequently the filler cap will be almost exactly flush with the exterior fuel tank skin surface (it is 0.63mm 6061-T6).

The 4mm x 13mm 73 TA-5-5 rivets chosen for this role have a grip range of 6.5-8mm. The total 3.2+2.4+0.63 = 6.23mm is just below the lower limit of the grip range of this rivet. However seeing the manner in which this type of rivet sets (it swells from the tip to within a couple of mm of the head in a totally uniform manner, if pulled in empty space) this 0.2mm difference should not affect the performance of this rivet. However I will make a decision on whether to purchase the next shorter rivet.

I have decided to do both - make the thinner flanges and purchase the shorter rivets.