Series C to bnc adpatper

Stuff you made and how to make cool stuff

Series C to bnc adpatper

Postby Doug Coulter » Sat Apr 23, 2011 8:41 pm

One of the joys of having even a modestly equipped machine shop is being able to "just do it" sometimes. I needed a series C male connector to do something on the new URSA MCA, and not one in sight anywhere. Looking it up, I see its an Amphenol part, low volume, so is sure to cost like those military $200 pliers, even if I could find someone who retails them who had them in stock.

Why wait? And why pay for the privilege of looking, looking, setting up a new account with someone, waiting, and so forth. Not much to this actually, only one "trick" was really involved, and it didn't take long either -- if I paid myself $100/hour, I probably made money over buying this, since it only took minutes.

A type C is like a BNC, but .540" OD on the female jack. Turns out 1/2" copper pipe is close enough, as it's a little over spec. So all I had to do was cut one up the right way, mill in the slots for the bayonet lugs, sweat in a 3/8" nut for the bnc, and make the center conductor.
SeriesCadapter.jpg
Homebrew adaptor


Here's the result. For grins, since I had it lying around, I even made a teflon center spacer to make it a little more robust, but it would work either way, and since I'm never going to take this off once on, it's pure nicety to have it in there anyway.

I milled out the bayonet slots with a 1/16" mill in my lathe toolpost grinder jig I've shown in other threads here. I made them real tight, so that's the real ground connection, and I didn't need to make the normal spiral to crank the connector on -- it's just tight fit and plenty good enough for a few uses. I used a wide angle pipe reamer to make it easy to start the nut for the BNC, and carefully soldered that in to the other end. Though the mech drawings on the web I found spec a 50 mil max center conductor, the reality is more like 80 mils for the particular connector I've got, so I took some number 16 wire (the correct nominal size) but then had to upset it (eg hit it with a hammer) to make it a little wider for good contact. The only "trick" here was getting it the right length for a fully screwed in BNC. Simple -- I made it too long, put the copper pipe on the receptacle, plugged in the center conductor, which held the whole BNC way out of the pipe, and measured the gap -- cut off that much, resolder, and done in just about the time it took to type this post.

And now I can try all those two wire/BNC scintillator heads on the new MCA, including the cute little Bicron one that arrived today. Sweet! Maybe we can find a bargain there too -- that Harshaw Cadillac model I have isn't exactly to be found on every street corner for cheap.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
User avatar
Doug Coulter
 
Posts: 3515
Joined: Wed Jul 14, 2010 7:05 pm
Location: Floyd county, VA, USA

Re: Series C to bnc adpatper

Postby Joe Jarski » Sun Apr 24, 2011 11:46 am

Nice - it's a great thing to have the equipment and materials on hand to do what you need when you need it. Having to order something or run to the store in the middle of a productive day (or night) always throws me off track. And like you Doug, it's about 15 miles for me to get to any type of store and the more useful ones are another 10 miles or so beyond that.
User avatar
Joe Jarski
 
Posts: 231
Joined: Thu Sep 16, 2010 8:37 pm
Location: SouthEast Michigan

Re: Series C to bnc adpatper

Postby Doug Coulter » Sun Apr 24, 2011 12:52 pm

Thanks! It works, and I'm right now running through all the scintillators that are ready to use, or close, to see what's what. Since we now have that killer gallon-jug NaI, which makes better spectra than the NaI spectra in wikipedia (no surprise there, these huge ones are rare), everything else is being compared to that, and I'm learning a bunch real fast. Over the next few days, I'll get even the "not ready to go" scints tested on this thing as well, who knows, for a lot of purposes, BGO or something else real cheap might be fine. I have found that real thin NaI's don't do high energies well (no big surprise) but do seem to resolve the low stuff tons better -- I can see a possible use for more than one in a lab, based on that. The big ones tend to have enough noise to obscure the low energy stuff, but the little ones show really pretty sharp lines there.

But I'll detail all this on a metrology thread, so we can all find it later...I should have some nice plots up there next week sometime. I'm getting some pretty ones now, but I want to go and label what's there. For example, an ages old (well, WW II) Ra source I have has a ton of daughters in it and isn't even close to a pure Ra spectrum. So why not figure out what peaks are what and document that? Maybe someone will chime in and give a link where that's all worked out, but I don't have it yet. I am at the point where I can tell refined U from ore quite easily....neat.
Kind of a radio-dating process -- few daughters in the fresh stuff, lots in the stuff "as old as the earth".

And yes, having to go out, or just stop when you were fired up on a project might not only slow it down, but push it to the bottom of the list, never to return sometimes. Better if you can just do it (which saying Nike stole from Zen). For me, I am fired up on whatever -- not the other things on the list, so if I get blocked on something, I may not just pick the next and be as productive on it. A lot of things sit on the list till I've had some flash of inspiration on how best to do it (and the stuff to do it with), and I've learned it's better to wait for that to come and not force it overly. Else I fall back into the software saying "rev two is the first one that works right" all too often.

Should I admit I made a little pipe stretching die to make .5" ID pipe into .540" id pipe before I even measured the pipe ID and found I didn't need it? Ah well, wife gets a little piece of 12l14 to take to the scrapyard.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
User avatar
Doug Coulter
 
Posts: 3515
Joined: Wed Jul 14, 2010 7:05 pm
Location: Floyd county, VA, USA


Return to Machining and Fabrication

Who is online

Users browsing this forum: No registered users and 3 guests

cron