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Port and Switch Alignment

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kevin.mcgee

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Good morning,
I am going to start building my L2 project with dual deployment soon. My question is how do you make sure your static ports on AV bay align with the screw switches on the electronics sled?
 

Donnager

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Measure 10 times, mark 5 times, drill once. :)

I have a couple AV bays where the sled can be rotated to align with the ports, and then tightened when the ports are aligned. This arrangement is the easiest one to get the screw switches aligned. I can tweak the sled location longitudinally to line it up the other direction.

Generally, I get a circumferential location by putting a card stock band on to trace a line, and use a couple of channels/angles to align along the rockets length.

On my fixed sleds, I seem to always be off by ~1/16" when I drill, but that is usually because of varied diameters of coupler and switch band, or bit walk if I didn't get a good start hole. I usually oversize the hole by a little because of this. I'd like to hear how others deal with it, though.

If you make a mistake, there's always more cardboard, fiberglass, epoxy, and body filler to make it right
 

Nytrunner

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Careful design, careful measurement prior to irreversible actions, and careful placement in accordance with that design.

I make sure the switch is mounted at the appropriate vertical position on the sled, then to ensure that the switch is always aligned with the appropriate hole, I'll either make a witness mark on the lid and coupler (line drawn across the joint) or make a physical key so that the lid only fits one way
 

Bowman

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Careful design, careful measurement prior to irreversible actions, and careful placement in accordance with that design.

I'll either make a witness mark on the lid and coupler (line drawn across the joint) or make a physical key so that the lid only fits one way
I did the witness mark on some of my rockets. Getting the sled aligned with the holes is always a challenge when prepping for flight. Sometimes requires four or five attempts to line-up.
I think future projects will incorporate the "key" approach, much more reliable to use.
 

David Schwantz

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Before you drill any switch or vent holes, install an alignment pin between the booster section to avbay and then from payload section to avbay. This keeps everything in perfect alignment as yuou drill and install switches and vents.
 

Tim51

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I don't have as much experience as some of the other posters, but personally I've found to my cost that witness marks and careful measurement that work fine on the bench can still lead to misalignments in the field - in one case at the pad, where for the life of me I couldn't access the switch and ended up standing down. Since then I've opted for keying with a small brass peg:
20210128_082634.jpg

As you can see re @Donnager's point "If you make a mistake, epoxy, and body filler to make it right" is apposite here 😊
 

OverTheTop

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I have been known to use an LED inside the airframe to locate the hole position. Otherwise, as others have said, measure five times and drill once.

I also locate the airframe sections using steel or CF pins which simplifies assembly.

If there are a lot of holes you can identify which had the switch with a vinyl decal.

DSC04760resize.JPG
 

Dudeman247.

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I have been known to use an LED inside the airframe to locate the hole position. Otherwise, as others have said, measure five times and drill once.

I also locate the airframe sections using steel or CF pins which simplifies assembly.

If there are a lot of holes you can identify which had the switch with a vinyl decal.

View attachment 448278
What does RBF mean down under? Has a different meaning where I pound sand...
 

Zeus-cat

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Magnetic switches from Featherweight. You only need to be close to get it to turn on.
 
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