Ok - lots of measuring 8 times and drilling once today..
First up: alignment keys:
Used a 6mm dowel left over from an ikea flat pack. I knew they’d come in handy one day!
Without a drill press, trying to drill half the switchband was a wash, so I just drilled the holes as close to the SWband as I could.
Inserted and epoxied the dowels and left 2mm inside the coupler:
I’ve started drilling smaller lead-in holes first and I’m liking the results. Wish I’d done that sooner with other builds.
Next was making the matching notches in the fin can and the payload bay tubes with a round hand file. I had a brainwave 1/2 way through the second notch and used a piece of 6mm all thread - much faster and perfectly sized...
Carefully cut off the excess with a hobby saw, then used the dremel sanding drum to flatten
I’ve got static ports * 3 aligned at 120° with one hole on the rail side (so my deadpool decal is not perturbed!)
I’ve got 4x 4mm plastic rivets to bolt the payload tube to the fwd of the eBay - these are aligned with the fins.
I’ve got 3x 2mm holes for fincan shear pins that are inverted from the three static ports. I opted to use some aluminium can epoxied to toughen up the ID of the PML phoenolic Tube where the shear pins will go:
Once the epoxy cures, I’ll drill the shear pin holes. I’ll likely also thin ca the coupler outside as well.
Then I will repeat with 3x shear pin holes for payload to NC...
Igniters and last bits of recovery gear are on the way from my LRV now and I’ve scrounged up 3G of 4fBP leftover from other flights so that will let me do 1.5 ground tests at home. If it isn’t successful, next ground tests will need to be done at the club field as I don’t yet have an explosives license that lets me buy BP...