Suggestions for electronics mounting hardware?

[mtnmanak]

My struggle is that places like McMaster-Carr have great products but I don't want or need 100 of something.

I understand this sentiment and I too used to feel the same way - why buy in bulk when all I need is 4 of something? Usually, in the long term, that way of thinking came to bite me in the rear (and wallet).

For this discussion, in your first dual-deploy rocket, you may only need 4 screws, 4 standoffs, 4 nuts, etc. However, if you decide you are going to build and fly dual-deploy rockets in the future, a single rocket can actually take a lot of hardware. Consider a typical dual-deploy rocket with redundant flight computers and a GPS tracker installed. Assuming each of the flight computers has 4 mounting holes and the tracker has 2 mounting holes, you would need at least 10 pieces of each kind of hardware for that one rocket. As the rockets get more complex (staging, airstarts, other cool things), that requirement may go up, but even at 10 pieces of hardware each, you would only get 10 rockets out of a box of 100 of something. And the per piece cost in that box of 100 would be much, much lower than trying to buy each part in small quantities. You would probably reach an ROI at just 2-3 rockets. Finally, the really small boxes that McMaster ships the small hardware in store a lot easier than bags or most other organization methods.

At the end of the day, if you plan to build more than a few dual-deploy rockets in your life, just get the box of 100 of something.

 

[cerving]

Yup, you'd be amazed at how fast you can go through 100 screws, and especially 100 nuts (they get lost really easy). They carry #2 and #4 short Nylon screws, too... great for shear pins. You WILL go through 100 of those, really fast if you fly a lot. I usually buy 2 or 3 boxes at a time.

 

[ClarkusAurelius]

I understand this sentiment and I too used to feel the same way - why buy in bulk when all I need is 4 of something? Usually, in the long term, that way of thinking came to bite me in the rear (and wallet).

For this discussion, in your first dual-deploy rocket, you may only need 4 screws, 4 standoffs, 4 nuts, etc. However, if you decide you are going to build and fly dual-deploy rockets in the future, a single rocket can actually take a lot of hardware. Consider a typical dual-deploy rocket with redundant flight computers and a GPS tracker installed. Assuming each of the flight computers has 4 mounting holes and the tracker has 2 mounting holes, you would need at least 10 pieces of each kind of hardware for that one rocket. As the rockets get more complex (staging, airstarts, other cool things), that requirement may go up, but even at 10 pieces of hardware each, you would only get 10 rockets out of a box of 100 of something. And the per piece cost in that box of 100 would be much, much lower than trying to buy each part in small quantities. You would probably reach an ROI at just 2-3 rockets. Finally, the really small boxes that McMaster ships the small hardware in store a lot easier than bags or most other organization methods.

At the end of the day, if you plan to build more than a few dual-deploy rockets in your life, just get the box of 100 of something.

That's a good point. I hadn't thought about the large number of parts needed for just one dual deploy rocket. Now that I've seen the parts in person I have a much better idea of what I'm working with. Not sure what my rocket future looks like right now in terms of number of rockets but 100 doesn't seem like all that much now. Would love to be able to have more than a few dual deploy rockets. My initial trepidation was not knowing what sizes I needed of anything. I'm fine ordering 100 of something if I know I'm going to use it but not so happy about ordering 100 of something I'm not even sure is the right size or that I will use. I'm much less confused now and on may way toward dual deploy. Thanks!

 

[ClarkusAurelius]

Yup, you'd be amazed at how fast you can go through 100 screws, and especially 100 nuts (they get lost really easy). They carry #2 and #4 short Nylon screws, too... great for shear pins. You WILL go through 100 of those, really fast if you fly a lot. I usually buy 2 or 3 boxes at a time.

Do most of your Eggtimer products use 4-40 stuff? I like your products a lot so far and want to continue to support your business.

 

[mtnmanak]

If you stick with 4-40 parts, you will pretty much cover 95%+ of the flight computers and trackers out there. I can't think of anything I normally use that doesn't work with 4-40 hardware.

 

[OzHybrid]

Nylon standoffs, screws and nuts can save a significant amount of weight if weight is significant to you. For larger rockets, it's probably not relevant.

 

[lr64]

Nylon standoffs, screws and nuts can save a significant amount of weight if weight is significant to you. For larger rockets, it's probably not relevant.

The standoffs probably save a lot more weight than the screws and nuts do.

 

[ClarkusAurelius]

If you stick with 4-40 parts, you will pretty much cover 95%+ of the flight computers and trackers out there. I can't think of anything I normally use that doesn't work with 4-40 hardware.

That helps me a bunch, and lessens my concerns ordering 100 of something

 

[cerving]

Do most of your Eggtimer products use 4-40 stuff? I like your products a lot so far and want to continue to support your business.

Yes, almost everything uses 4-40. I think there's one exception left, it's either the Eggfinder Mini or the Quark... I'd have to check the boards.

 

[cls]

That helps me a bunch, and lessens my concerns ordering 100 of something

Hi, let me encourage you to get boxes of 100 at a time. At this point I have built a good collection and don't need to run to the hardware store for any dumb little parts, can finish a job in one sitting.

Feels like a small victory against the universe, which is conspiring to enforce the law that any simple project requires 3 trips to the hardware store!

 

[Onebadhawk]

Go to my "U-Bolts" page..
Then scroll down a lot..
You'll see detailed pics of my bullet proof av bay..

https://onebadhawk.com/stainless-steel-u--bolts.html

Teddy

 

[WizardOfBoz]

I have limited experience in mounting electronics. I did buy a bunch of 4-40 screws, nuts, and standoffs. They were too big for the Eggtimer Altimeter, but I made it work. More recently, I build Cris Erving's Eggtimer EZ-DD. The mounting of the flight computer and battery were with long screws, plywood, and (I think) balsa wood blocks. IMHO, this setup is secure and is probably the least expensive way to mount stuff. Yes, the printed sleds are very nice and look cool but I suspect that in terms of weight, durability, and cost the fabricated plywood setup is superior. Others with more experience can chime in and correct me if I'm wrong.

BTW, the Kevlar(TM) loops on each bulkhead were tied with a Reever knot, with the loose end buried in the opposite end of the line. The Reever knot , a favorite of mine, is very good for Kevlar, and burying the end avoids Kevlar's omnipresent unraveling without using any glue that would make the line rigid and provide a stressor.

On edit: Just looked at the pics of avbays provided by @Onebadhawk , in the previous post. Horses for courses. I am certain that the avbay below will be fine for F-I motors. When I try for an MD 75mm rocket, I want one of @Onebadhawk 's setups! They look bomb-proof.

 

[Flare]

Yes, almost everything uses 4-40. I think there's one exception left, it's either the Eggfinder Mini or the Quark... I'd have to check the boards.

Quark holes are smaller. 2-56 or so. I have used M2s.

4-40 and 2-56 (~M2) will basically be all you need for rocketry stuff. I use both of those sizes for various mounting and/or shear pins, buy em from Mcmaster carr by the 100.

With regards to mounting electronics I build my standoffs into my 3d printed avbays, and then use heat-set metal inserts (also from Mcmaster) to thread into.