Using standard screws for terminals?

Zyzzyva1000

Well-Known Member
TRF Supporter
Joined
Jan 15, 2022
Messages
73
Reaction score
32
Location
Kentucky
I am putting together a 38 mm minimum diameter rocket and decided to add an electronics bay. I have not needed to work in such a tight space before, and I am trying to figure out the best way to setup the bulkheads. I have 3d printed some charge well to fit, so I have that taken care of.

My standard terminal blocks I use are too bulky and won't fit. I was thinking of just doing screw terminals (similar to what I have done using the mounting kit available from eggtimer for my nose cone mounted apogee altimeter). Is there any reason a long machine screw wouldn't work as a terminal? My plan is to have a standard nut up against the bulkhead on each side to keep it in place, and then 2 washers (between which I will trap the wire), with a final nut on top to compress it all together. Anyone know of better ways to do this? I have always had room to use a terminal block on my larger projects, just trying to figure out how to conserve space here.
 

waltr

Well-Known Member
Joined
Jul 17, 2021
Messages
1,172
Reaction score
691
Location
SE Pennsylvania
That would work fine and I have seen some pictures of ebays setup this way.

Do inspect and clean before each flight.

I have never used terminal blocks on ebays. What I do is run the ematch wire through the bulkhead and connect directly to the altimeter terminals. Then a little bit of 'duct seal' (putty) to seal the wire holes.
Yes, the ebay must be opened to do this but one needs to check/change the battery anyway.
I install the ematches at home while preping the rocket. Then add BP before launch.

Just saw Titan I suggests the same thing.
 

Handeman

Well-Known Member
TRF Supporter
Joined
Jan 18, 2009
Messages
8,268
Reaction score
841
Location
Stafford, VA
I only open my av-bays every couple of years when they need new batteries so I always use terminals. The machine screws will work. I would suggest ring terminals on the wires to the inside of the machine screws in case you tighten the nut too much and make the screw spin slightly. It could break a wire, but not the ring terminal.

The screws do add weight where wires through to the altimeter doesn't. That may be a big consideration on a minimum diameter rocket.
 

Zyzzyva1000

Well-Known Member
TRF Supporter
Joined
Jan 15, 2022
Messages
73
Reaction score
32
Location
Kentucky
Yea Maybe I am over thinking this. Since I have less space to work its probably better to just keep it simple. I was wondering what to use as a sealant - I will get some of that duct seal putty. Thanks!
 

Zyzzyva1000

Well-Known Member
TRF Supporter
Joined
Jan 15, 2022
Messages
73
Reaction score
32
Location
Kentucky
I only open my av-bays every couple of years when they need new batteries so I always use terminals. The machine screws will work. I would suggest ring terminals on the wires to the inside of the machine screws in case you tighten the nut too much and make the screw spin slightly. It could break a wire, but not the ring terminal.

The screws do add weight where wires through to the altimeter doesn't. That may be a big consideration on a minimum diameter rocket.
Good call on the ring terminals. I will keep this in mind for future projects.
 

Kane

Active Member
TRF Supporter
Joined
Nov 29, 2020
Messages
33
Reaction score
25
I have used Lab Rat's terminals I'm the past. They work very well - especially for smaller airframes.
 

Attachments

  • 16702613482103682374632459224362.jpg
    16702613482103682374632459224362.jpg
    533.2 KB · Views: 0

mbeels

Yes balsa
TRF Supporter
Joined
Feb 9, 2019
Messages
3,124
Reaction score
1,867
Location
SE PA
I've used screws before just as you describe, and it worked fine. For the final nut, I used "thumb nut" to make it easy.

1670261539711.png
 

Voyager1

Well-Known Member
TRF Supporter
Joined
Oct 23, 2015
Messages
935
Reaction score
361
Location
Australia
Yea Maybe I am over thinking this. Since I have less space to work its probably better to just keep it simple. I was wondering what to use as a sealant - I will get some of that duct seal putty. Thanks!
I often just use masking tape to seal over the ignition lead holes in the bulkplate.
 

Crazyrocket

Well-Known Member
Joined
Jan 18, 2009
Messages
821
Reaction score
54
I also use the non-drying kids putty that comes in different colors (cannot think of the name right now). Easy to use and I put it on both sides of the ebay lids. When done, just remove the putty and clean the holes with a toothpick.
 

cerving

Owner, Eggtimer Rocketry
TRF Sponsor
TRF Supporter
Joined
Feb 3, 2012
Messages
5,465
Reaction score
3,548
Just got these for my Airstrike 3829... Integrates through-bulkhead connectors with your charge well in a small form factor.

(scroll down to the very bottom)

Those are basically the Doghouse Rocketry through-bulkhead charge wells, they work fine but I've had a few crack on me when they fired. Hopefully they've improved that... I haven't used them in a few years.
 

pbahorich

Well-Known Member
TRF Supporter
Joined
May 8, 2020
Messages
56
Reaction score
62
Those are basically the Doghouse Rocketry through-bulkhead charge wells, they work fine but I've had a few crack on me when they fired. Hopefully they've improved that... I haven't used them in a few years.
They've worked well for me with up to 3 grams of FFFFg black powder, so they must have improved that..
 
Top