Key switch with 1/2" barrel?

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Bat-mite

Rocketeer in MD
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I am getting a little tired of the fragility of Schurter 100/220 switches and want to move all my rockets to key switches. However, the ones Aerocon sells require a 3/4" hole. On my smaller rockets, I have a 1" switch band, leaving only 1/8" on either side of the switch.

Does anyone know where to get a key switch with a 1/2" barrel?

BTW, this thread is not intended as a discussion of "what is the best switch?" There are already those threads. I know some of you only use mag switches, and some twist and tie, and some screw switches. Please, just tell me if you know where to get a key switch with a 1/2" barrel. Thanks.
 
I have found several by Internetting, but most of them extend pretty deeply into the hole. For a 3" airframe, I can't have a >1" barrel + terminal length. That would be another consideration.
 
I scavenged an old keyswitch off of a PC case (must've been an x386, lol)- it's pretty small, but also doesn't seem terribly robust. I'll take a photo when I get home. I was thinking of incorporating it into a launch lock-out, not sure I would trust it on a rocket. I can't seem to find any similar on the interwebs, surprisingly. It's quite old tech, though.
 
That’s a safety issue then. Anyone who finds a rocket should be able to disarm it.

1) That's not in the safety code; and 2) I know a ton of people who use key switches. If it has a magnetic switch, does everyone carry a magnet? If it has a screw switch, does everyone carry a long, thin screwdriver? If it has a wi-fi switch ...

People who find my rocket should leave it alone and let me know where it is.
 
1) That's not in the safety code; and 2) I know a ton of people who use key switches. If it has a magnetic switch, does everyone carry a magnet? If it has a screw switch, does everyone carry a long, thin screwdriver? If it has a wi-fi switch ...

People who find my rocket should leave it alone and let me know where it is.

1) You’re right; and I hope we don’t get to the point where we need to put every single thing into the safety codes. We are expected to have good judgement. When things need to be added to the safety codes it’s usually after something bad has happened.
2) That many people do something doesn’t make it a best practice (or even a good practice). At least with the other switches you’ve named other rocketry people would know what to do and could do it; with a key switch that ability is denied them.
Key switches are designed to add security, not reliability. I’ve never seen one that has a shock rating.
I can tell that you resent my suggestions. I’ll butt out.
 
1) That's not in the safety code; and 2) I know a ton of people who use key switches. If it has a magnetic switch, does everyone carry a magnet? If it has a screw switch, does everyone carry a long, thin screwdriver? If it has a wi-fi switch ...

People who find my rocket should leave it alone and let me know where it is.

^This. +1 Common sense prevails.

Even if Joe Sixpack was ambling around in the middle of a cornfield with a pocket full of tools, how would he even know that a rocket required "disarming" and how to go about doing it?

I pisses me off when others pick up my rocket during a launch event, especially when I am in clear sight and making my way to the landing site. Good intentioned or not, it isn't yours, so don't touch it.
 
^This. +1 Common sense prevails.

Even if Joe Sixpack was ambling around in the middle of a cornfield with a pocket full of tools, how would he even know that a rocket required "disarming" and how to go about doing it?

I pisses me off when others pick up my rocket during a launch event, especially when I am in clear sight and making my way to the landing site. Good intentioned or not, it isn't yours, so don't touch it.

I agree for some ranges, but depending on where a person launches there may be other people who pick it up for various reasons. We’ve had ranchers pick up rockets because the parachute was dragging the rocket across their pasture and scaring their calves. We’ve had rockets found a day after the launch by people who were not part of the launch. We’ve had rockets drift a few miles. If a rocket of mine with hundreds of dollars worth of hardware drifts a few miles from the launch site I want whoever finds it to be able to pick it up and notify me. Especially if I’m three states away when it’s found.
 
1) You’re right; and I hope we don’t get to the point where we need to put every single thing into the safety codes. We are expected to have good judgement. When things need to be added to the safety codes it’s usually after something bad has happened.
2) That many people do something doesn’t make it a best practice (or even a good practice). At least with the other switches you’ve named other rocketry people would know what to do and could do it; with a key switch that ability is denied them.
Key switches are designed to add security, not reliability. I’ve never seen one that has a shock rating.
I can tell that you resent my suggestions. I’ll butt out.

Please no, not resentment!
Disagreement,and a little befuddlement. There is nothing more dangerous than forgetting to arm your electronics on the pad, right? And switches that give no indication from a distance that the electronics are not armed could be said to be very unsafe for that reason.

I've read lots of threads where people say that they sometimes forget to arm their electronics at the pad. Thus, the invention of the "remove before flight" tags. These tags, as far as I can tell, only work with key switches, because no other switches have a removable part. So in that sense, key switches are the safest.

I just can't imagine a scenario in which a grounded rocket with a magnetic switch is safer than one with a key switch. I may be the only one with the key, but I also may be the only one with the magnet or the wi-fi controller; but I am also very likely out looking for my rocket with those things in my pocket. I am not expecting anyone to carry my rocket back to the flight line while it is armed, no matter what kind of switch is in it.

Of course, all of this presumes that I have not abandoned my rocket and gone home. But I can promise you that if I find someone else's rocket on the ground armed with a mag switch, pull switch, or wi-fi switch, I am not going to be able to turn it off. I might have a Leatherman in my pocket, but that's about it.
 
A few minutes search for key switches on Digikey, filtered for SPST and 2-positions yielded a few hits. This linked switch has less than 1/2" panel cutout dimensions on an oval shaped hole. It is limited to 1.0A current though. A little time searching through the options may possibly turn up a unit suitable for your application.

https://www.digikey.com/product-detail/en/e-switch/KO106A102/EG2625-ND/502089
 
I also like the concept of the REMOVE BEFORE FLIGHT tags. This thread shows a very good way to use those.
https://www.rocketryforum.com/showthread.php?143967-Break-Make-Plug-i-e-the-Remove-before-flight
I agree, a person probably won’t have the necessary tools to disarm anything other than a slide switch or toggle switch and sometimes those are behind a hatch, but for almost any kind of switch other than key switches you could talk them through it. I even like Schurter switches better than key switches.
Those ones ECarson linked should be fine. The 1 amp rating is probably the load that it can interrupt, not the max current capacity.
 
There was a thread here that showed high grade slide switches being used with "on" being the down position on the switches. The users swore by them and exclaimed no mishaps and easy for anyone to turn off the electronics.
I was incredulous but I can't argue with someone who has successs with this strategy. I wished I saved the thread. They weren't cheap switches either. I've used locking toggles: https://www.goldmine-elec-products.com/prodinfo.asp?number=G20892
for apogee only events. I stick 'em on the bulkhead (of smaller stuff mind you). Place rocket on the pad, lift the upper bay off, turn on the switch and lower it to the sustainer. Great for a MAD unit. Once the charge fires, I don't care what happens to the
switch because it's a single event. After over 20 flights, I always notice the switch is still locked on and have to manually shut is off. Kurt
 
A few minutes search for key switches on Digikey, filtered for SPST and 2-positions yielded a few hits. This linked switch has less than 1/2" panel cutout dimensions on an oval shaped hole. It is limited to 1.0A current though. A little time searching through the options may possibly turn up a unit suitable for your application.

https://www.digikey.com/product-detail/en/e-switch/KO106A102/EG2625-ND/502089

I've used switches like that and have flown them for years without issue. Kurt
 
I've read lots of threads where people say that they sometimes forget to arm their electronics at the pad. Thus, the invention of the "remove before flight" tags. These tags, as far as I can tell, only work with key switches, because no other switches have a removable part. So in that sense, key switches are the safest.
I use them on pull-pins, not key switches.

Either way if somebody doesn't know how to turn it off the result is the same.

I choose small batteries for my electronics. That way I know that once the rocket has flown it will be relatively well safed an hour or two after the flight because the relevant battery(s) have gone flat.

We do what we can. Sometimes things are not 100% achievable, but rather noble goals.
 
I've read lots of threads where people say that they sometimes forget to arm their electronics at the pad. Thus, the invention of the "remove before flight" tags. These tags, as far as I can tell, only work with key switches, because no other switches have a removable part. So in that sense, key switches are the safest.


The workaround I've found for this.... I tie a piece of paracord to my RBF tag (It's one of the big 2 foot long ones) and smush the end of the paracord into one of the vent holes. It's not foolproof but it saved my butt at the last launch I went to.
 
John, I picked up some key switches in an electronics misc lot and they are for .5" hole and the total length is .78" with ~.5" (depending on wall thickness) extending into the tube. I have 4 of them and a longer 4 prong one. I'm not gonna be at an MDRA launch till March or April but I'd be happy to set 1 or 2 aside for you.
 
John, Did you receive the switches you ordered? I'm curious what you think of them.

I did. Shipping was quick. They seem durable and look nice. The disappointment is that the key is removable in both positions, which means it could be off without the flag in it. This is not a best case scenario. But my main need is something more durable than plastic, which I believe they are.
 
I have a few that key only removes in the on position. I bought them from a surplus supplier years ago. Wish I would have bought more than 4 :( They are no longer available.
 
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