Anyone recognize these tailcone fasteners?

[DIVANS]

I believe I accurately answered the original post question “does anyone recognize these fasteners”. I have been amassing spare parts for my soon to be one year old aircraft and I was curious why there was no mention/depiction in the KAI of the flush washers used with the 2) AN507C832R8 machine screws attaching the upper cowl hinge pin cover panel (F-1240B) as well as additional locations using the AN507 screws (upper firewall, forward stab skin (VS-1204)).

The flush washers are only used with the AN507C832R8 screws which in turn are used with countersunk ALCLAD sheet. The fiberglass cowl is not countersunk. The cowl is attached with AN525 screws using nylon washers.

I do not think the flush washers provide any structural benefit. I believe Van’s utilizes them on their SLSA builds solely to mitigate paint damage.

[climberrn]

Originally Posted by seagull

I saw these in Tony S post. Does anyone recognize the washers used? They are smaller OD than Tinnerman's.

Attachment 39519

Easy to make. Thin SS washers from McMaster Carr, dimple each washer, Done. I use these for a cleaner look on some fiberglass. 700 flying hours, and no hole enlargement. Keeps the paint from chipping some, and yes, I keep a stock of Tinnerman washers for use where needed. Simple to convert fiberglass holes to accept Tinnerman at a later date if needed.

[dmattmul]

I went with these after my painter did not replace my Tinnerman washers on my wheel pants. Was told once you use Tinnerman it will damage (scratch) the paint (Under the Tinnerman washer) which is ok as the washer should hide any scratching it produces but you need to leave it on. Like the Tinnerman washers these help spread the load. 100 deg countersunk screws seem to fit well. So far, no paint scratching. I preferred to try and stay away from the Tinnerman and insured extra fiberglass was used to give the area more support, but the front wheel pant gets a lot of vibration. After about 50 hrs. they are holding up well and have not scratched the paint. They also come in many colors.

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