Don't have a D-punch, only a drill - Page 1
Forum section: electronics / beginners

author: py-bb
author_rank: Regular Contributor
timestamp: July 22, 2023, 02:03:41 am
content: Hi there,I need to mount some BNC connectors and some barrel jacks. The BNC connectors have a "D" shaped cross-section and should go in a D shaped hole, these often experience a lot of twisting so I don't expect there's a "drill trick" to get them to stick - that said, can't hurt to ask.I'm more asking about the barrel jack's female side. The threads which the nut goes on (thus securing the jack in place) have 2 "worn sides" (it's clearly by design) - it's 10.5mm where they're "worn" and 11.5 where they're not.If I drill an 11mm hole, maybe 10 and work it a bit, can I just stick some electrical tape around it (not for isolation electrically - it's plastic) and that'll stop it from rotating too much?Any tips and tricks?Thanks

author: coppercone2
author_rank: Super Contributor
timestamp: July 22, 2023, 02:20:28 am
content: use a file

author: py-bb
author_rank: Regular Contributor
timestamp: July 22, 2023, 02:29:33 am
content: Quote from: coppercone2 on July 22, 2023, 02:20:28 amDrill a size down and round out the hole?

author: David Aurora
author_rank: Frequent Contributor
timestamp: July 22, 2023, 02:54:23 am
content: Yeah, until I got my CNC machine I always just drilled smaller and filed to taste. Unless you need to do a tonne of them it's pretty quick and easy

author: alpher
author_rank: Frequent Contributor
timestamp: July 22, 2023, 03:39:14 am
content: Why don't buy a punch? I'm sure something reasonable can be found on ebay?Recently there is a plentiful of "cheap" punches available there, at least compared to what greenlee would charge.

author: KE5FX
author_rank: Super Contributor
timestamp: July 22, 2023, 04:05:39 am
content: When I mount SMA jacks to a panel, I often put down a strip of copper tape first and solder the back of the jack to the tape. This trick is surprisingly good at keeping the jack from spinning in place. Should work for BNCs as well, I imagine.

author: coppercone2
author_rank: Super Contributor
timestamp: July 22, 2023, 05:36:44 am
content: or just get a flanged connector they are superior in every way

author: edpalmer42
author_rank: Super Contributor
timestamp: July 22, 2023, 06:05:41 am
content: Something like this would work. Just drill a hole, then a minute with a small file to open up a notch and you're done.I wish it was available in metal, but I'm sure that would be crazy expensive - even the nylon ones are pricey.https://ccsukltd.co.uk/INSULATING-WASHER-BNC-TNC-MOUNTING-PAD-10221-ST100539?search=bnc%20washerEd

author: coppercone2
author_rank: Super Contributor
timestamp: July 22, 2023, 06:25:32 am
content: this won't rotate I promise

author: py-bb
author_rank: Regular Contributor
timestamp: July 22, 2023, 07:51:34 am
content: The backup plan is to 3d print something similar - we need isolated ones!Quote from: coppercone2 on July 22, 2023, 06:25:32 am

author: EPAIII
author_rank: Super Contributor
timestamp: July 22, 2023, 10:46:00 am
content: I have confronted this exact problem several times over the years while constructing custom video devices.You say you are mounting them in plastic. Probably the easiest way is to file a couple of notches in the area where you want the flat and add some epoxy when you assemble things. The notches do not need to be fancy: a triangular file will work nicely. If you want disassembly to be possible, then coat the surfaces with grease before applying the epoxy.As for my prior ideas I have a folder on my hard drive with the partial design of a tool to convert round holes to D shaped holes in metal. The idea was to squeeze some metal from the outside of the hole into it. I called it my R2DTool: Round to D Tool. I never built one.

author: TimFox
author_rank: Super Contributor
timestamp: July 22, 2023, 01:37:31 pm
content: A cheap idea that works reasonably well for anti-rotation:Drill the normal 3/8 inch hole, then take a center punch and punch just outside the hole to get a "dent" into the hole.

author: Stray Electron
author_rank: Super Contributor
timestamp: July 22, 2023, 01:49:56 pm
content: Quote from: py-bb on July 22, 2023, 02:29:33 amDrill a slightly undersized round hole and then file it to the size and shape that you want.If your desired hole is very large, you can drill a series of small holes just inside of the outline and then remove the inner portion and then file the large hole to shape.They (Greenlee IIRC) do make D-shaped chassis punches for many standard connector shapes but they're very expensive if you buy them new.

author: coppercone2
author_rank: Super Contributor
timestamp: July 22, 2023, 02:40:42 pm
content: https://www.amazon.com/Neutrik-NBB75DFIB-P-Receptacle-feedthrough-Isolated-Black/dp/B00BUG7S0I

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: July 22, 2023, 02:49:36 pm
content: Hi,just like edpalmer42 said, use these (picture) and save a lot pf time and hassel...Good luck

author: edavid
author_rank: Super Contributor
timestamp: July 22, 2023, 02:52:21 pm
content: Quote from: edpalmer42 on July 22, 2023, 06:05:41 amDoes anyone know a US source?

author: Veteran68
author_rank: Frequent Contributor
timestamp: July 22, 2023, 03:31:25 pm
content: Quote from: edavid on July 22, 2023, 02:52:21 pmhttps://www.l-com.com/patch-panel-server-rack-insulating-washers-bag-of-10-washer-pairs

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: July 22, 2023, 03:44:28 pm
content: Hi Veteran68,Quote from: Veteran68 on July 22, 2023, 03:31:25 pmNot the exact type, they lack the "nose".The patch-panel-washers need a D-form hole as well.Best regards