Expanding some cases, ideas?

I need a metal casing to enclose an electronics project (it needs a shield around it to exclude electrical noise so a shell casing came to mind.)

Think it's going to take a 50 BMG case to do this.

So I need to turn the 50 BMG casing I got, into a straight-walled case so I can fit the printed circuit board into it.

I am guessing something like a steel tapered pin driven in there should do the job? In several stages, maybe with annealing it before / during. Thinking on it.

I could try fire forming it in a 12Ga but no idea what load would do it :) Maybe a large O ring or the like to retain the case so the primer strike fires it.

If someone has a better idea, I am sure game; Not in a huge hurry but want to get this done once I get two more things over with and get to this one.

Thank you, all :)

You can't just cut the bottle neck portion off? Do you need the entire length?

For the amount of effort you might be better off with a section of copper pipe and a couple of end caps. Does the shield need to be closed on both ends? Maybe just a section of copper pipe without the appearance of a bomb-like pipe with two end caps and wires hanging out:-)

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Originally Posted by Petrol & Powder

You can't just cut the bottle neck portion off? Do you need the entire length?

For the amount of effort you might be better off with a section of copper pipe and a couple of end caps. Does the shield need to be closed on both ends? Maybe just a section of copper pipe without the appearance of a bomb-like pipe with two end caps and wires hanging out:-)

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Great idea, much safer too!

The copper tubing idea sure seems to be the simple answer, or do you need the thickness and weight of the BMG?

Another option would be a solid brass 12 gauge case, or if too short, two of them, mouth to mouth, with wrap or two of electrical tape to hold together.

aluminium foil wrapped around pvc pipe

I'm not into circut board type electronics. I have built a lot of switching units and corded remotes for
farm machinery. I use Carlon PVC boxes wich can be bought in many sizes. The remote switches I
put in Carlin PVC 1/2" electrical conduit, capped on the ends. 3/4" is also available if the extra space
is needed. I don't know if PVC would provide the shielding you need. If not the copper tube would be
next best thing. There is also Stainless Steel tube available from industrial supply outlets. I once put
a remote corded micro switch in a section of 12g shotgun magazine with a bicycle grip on it for class.
In a pinch a 50cal brass will make a adapter from 3/4" to 1/2" copper tube. This is probably classed
as Red Neck Tech compared to your project.

Copper pipe would make an ugly, graceless enclosure though. I am trying to make this look sorta elegant or at least functional :) Has to be metal and well grounded, there will be a metal pin out one end (Probably the primer hole, drilled out) and cord out the neck hole so it has very good strain relief. I'll figure something out :)

Well a 50 BMG casing would be more elegant than a piece of copper pipe but if you need to open the neck up in order to get the circuit board inside, you still might be better off with a section of 3/4" or 1" copper pipe.
By the time you expand the neck and drill out the primer pocket, you could likely make 2 or 3 units with a simple section of copper pipe and end caps.

Rigid copper tubing ___ in the lathe __ cut ends true __ counterbore one half the thickness of the tubing to a depth 0.40 plus the thickness of a round copper plug (penny) . Drill the wire holes in the plug. Assemble and put in the plugs and using a sharp point punch , peen three times around perifery at 120 degrees holding in the plug. Could be taken apart by unpeening from the inside for repairs. Then the outside of the rigid tubing could be held in a milling machine and made to look fancy with some fancy cutting. Then on to the chrome plating. Well, I didn't have much to do with my idle mind right now, so there is my story and I am sticking to it.

That would work but the cost in labor would be a lot higher than a section of 1" copper pipe, 45 seconds with a tubing cutting and slipping two end caps (one with a hole drilled in it) onto the pipe.......

No lathe, no counter bore, no pennies, no peening, no chrome plating, no fancy cutting but an adequate electronic shield. :D

But Mr Sheesh said copper pipe is ugly and graceless. He wants something elegant and functional, reason for fancy cutting , chrome plating and no graceless copper caps. Heh Heh Heh & LOL

No lathe here :/ I just like the idea of a nice case as an enclosure, mumble.

Mr Sheesh

Can you give some dimensions of what would work ie,
length,inside/outside sizes, dimensions of holes need etc.

I have some Ideas, but need some info to work with,
what colors would accept, Polished/coated copper, nickle spiraled design etc.

Tia,
Don

Copper pipe and end caps, simple and can be had in many sizes.

My friend who was over today (we're making at least one of these apiece) thinks a 50BMG case may be too short, BUT, he hasn't seen how good I am at cramming prototypes into minimal space. (Used to do that for a local company, I could put through hole parts together to match the density you'd get with SM0805 parts, by stacking parts above the board and cutting parts of the socket off, trimming the frame, and so on.) I haven't done schematic entry yet, much less done the PC board, but I suspect I can fit it in a straightened out 50BMG case, I have a LOT of tricks I can use, if I have to go higher tech and get PC boards made commercially that'll let me do even tighter boards. I'll know in 2-3 days depending on what interruptions happen :)

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Originally Posted by Mr_Sheesh

No lathe here :/ I just like the idea of a nice case as an enclosure, mumble.

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I get it ;) Have fun with your project.

Would an aluminum cigar case work?

What about a 20mm, 30mm or 40mm shell cases?

Tia,
Don

I'd thought of an Al cigar case but didn't think they're quite strong enough. I'm concerned that I'd mash it either in transporting it or in use. The 50 is large enough, if I used a 20mm shell or larger that's getting a bit unwieldy to hold in your hand, tracing out a signal, short of making a forearm attachment for it and then a short piece of co-ax to the probe tip; If I have to go that way I'd just use a flat, wider Al enclosure. Trying to make it a one-hand dealie :)

How about using some brass pipe?. 1/2", and up and readily available at Lowe's or Home Depot. And they even make brass pipe caps. Polishes up nice and the ones I have the pipe caps are machined not cast then threaded. Just a thought. Frank

Trying to make a GRACEFUL looking enclosure, those pipe caps look obnoxious to me; Maybe if I figured out a way to put internal caps inside the pipe, but the traditional copper pipe caps just look ugly. A nice casing looks a lot more elegant IMO.

Use the copper pipe. When it's finished give it coat of varnish or poly. It will hold that color for decades.

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Originally Posted by samari46

How about using some brass pipe?. 1/2", and up and readily available at Lowe's or Home Depot. And they even make brass pipe caps. Polishes up nice and the ones I have the pipe caps are machined not cast then threaded. Just a thought. Frank

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I think brass tubing would be thin enough to be practical, still strong enough for use. You could solder end caps on made from flat stock. Even if oversize, they could be quickly and easily sanded/ground/filed to fit. No unsightly end caps. Could be internal or soldered to the end.

Why not use two 50 BMG cases? Cut the bottle necks off, stuff the card inside and silver solder (or just fit one into another) the two halves together. This way you can cut them to the exact size you need, and you can keep the shell "look" of the project.

I was digging around in my "stuff" and have this brass tubing. It is a bit heavier than the hobby tubing. It is 3/4" OD and about 0.66" ID. I have end caps that tap into the end. If interested, I can send you pictures by PM.

I have a some stainless tapered bars that were made for my old man by a machinest buddy. They
were made to drive through shotgun barrels to remove dents. They are for 12s & 20s. There are 3
of each. I don't know if they were made by measurements or brand of gun. I'm sure you could tap
a tapered pin in 50brass to take out neck. You just don't drive it in like its a nail. In Army guys use
to cut off a 50 and use two ball peen hammers to bell it out. Then used a 7x62 soldered in for a
stem to make a pipe. You would think brass would taste nasty, but they didn't care they weren't smoking Prince Albert.

I got the schematic together today, starting to work on the PC board. So far just one sided but if I make it 2 sided it'll be SMALL. I can make my own 1-sided boards here easily, "toner transfer" method, even 2-sided somewhat, but so far I think I can fit it inside the 50BMG case; Maybe even without expanding the case. (John, my friend who came up with the design idea for these, misled me on how complex these aren't. If I worked hard on them I think I could MAYBE fit them in a 45/70 or 30-06 casing, as a first guess. I might just do one old school to show him what can be done if you try :) LOL) He'd been saying they'd HAVE to be an inch longer than these casings and the PC Board an inch wide; I think I can do it in 1/2 that width on one side. It'll be fun to confuse him LOL

If you need longer the venerable 45-90 would fit in nicely. Thinner a 375 H&H would be a good stopper.
Then why not go big and load up a 50-110 !

Look into www.McMaster.com for brass tubing.

McMaster-Carr = if they don't have it, you don't need it. No minimum, but shipping can be pricey.

Even better - https://www.onlinemetals.com/merchan...p=2&top_cat=79

Do they not make brass tubing?

A Harbor Freight flashlight already has half the problem solved.

Have you looked at the oilers for 1903 Springfields, etc.? Gun Parts Corp (aka Numrich) purveys them -- https://www.gunpartscorp.com/products/413540C -- with them regularly appearing on popular auction sites at roughly one-half, and less, of this vendor's price. Made of brass, and chrome plated -- these may just work for your application?
geo

Here is a picture of the tubing and end cap. I can cut to length you want. Yours for the cost of shipping.

https://farm2.staticflickr.com/1975/...c568ba55_k.jpg