Hi Guys,
Well, I got the SKYBOLT fasteners/receptacles/retainers and today was the day to try them out. Since there was quite a bit of confusion on my part as I researched these fasteners I thought I would post a little information about them.
Thanks to Robbie Culver, David Amsler, et.al for help clearing the fog. As David pointed out, the printed catalog is a much better reference than just poking around on the SkyBolt web site (Ref.
http://skybolt.com/wp-content/uploads/2019/04/Skybolt-Catalog-v5.1_Print-aerospace-fasteners-1.pdf).
I chose to use one of the "CLoc 2000 Series Common Sets" (SK28S3-SET1). Here are the parts, less rivets, that make up the set.
A stud, a retainer, and an adjustable receptacle.
Here are the tools to work with the set.
The pliers and the drill jig will be familiar to anyone who has worked with CamLoc fasteners. The pick is used to assist with adjusting the receptacle once the "tang" is removed or to re-insert the tang (Ref.
http://skybolt.com/wp-content/uploads/2017/08/Instructions-SK213-SK215-SK245.pdf). The other tool is used to press the retaining washers onto the studs.
Here is a pic of one of the receptacles as I installed them.
I used solid rivets so the tang had to be removed to squeeze the rivets. The tangs went back in place easily using the pick.
If you are used to working with standard receptacles the adjustable ones look a little clunky. But, on the up side, you won't end up with a box full of unused studs that have the wrong grip :-) That is unless you bought the wrong studs.
The set I chose includes the SK8S3-2S stud. Here is a pic of some scrap held in place with one of the studs.
I like the look, but I don't really like the stud. The studs require a counter sink/dimple be applied to the 1/4" hole the stud fits in. And, as you may know, 1/4" fasteners are "self retaining", and
floating, as long as the hole is no larger than 1/4". Since the cowl flanges aren't very thick, by the time the counter sink is deep enough for the stud to sit flush, the 1/4" hole has been enlarged. There goes the self retention. Even if the material is thick enough that the hole is not enlarged, the fiberglass around the edges of the hole will be so thin that it is guaranteed to enlarge over time.
Pic of hole before and after counter sink is applied.
Pic of how the stud self retains.
So, I'm thinking about using one of the protruding head studs with a SS washer between the cowl and the stud. Kind of like this one only with a phillips head.
EDIT: That gives me an idea. Instead of using the supplied retaining washers I could use a thin 1/4" washer (AN960-416L) on the back side of the stud. Seems that would allow the stud to "float" and ensure stud retention even if the hole was slightly enlarged. Hmm... Also, I see that split ring retainers are available. It won't look as good, but I think it would perform better.
I don't know. Still over thinking it.
Wes