BNC sheet metal "D" punch - remanufacturing - where to get one? - Page 1
Forum section: electronics / general

author: hydrogen maser
author_rank: Regular Contributor
timestamp: December 19, 2016, 09:30:10 pm
content: This is not manufacturing but rather re-manufacturing and this seemed like the best place to post this question. I have a need to put BNC connectors into older equipment that have sheet metal cases and I am looking for a tool to punch D shaped holes of the correct size and shape to install BNC connectors. I have not found the right tool to do this - the issue is that most punches are designed for flat sheets before they have been bent - punch holes first, then bend to final shape, but I need to punch D holes in older equipment. Is there a tool out there that will do this?

author: edpalmer42
author_rank: Super Contributor
timestamp: December 19, 2016, 09:52:47 pm
content: Greenlee is the first brand name that comes to mind. But be sure you're sitting down when you look at the prices!I think most of us peasants just drill a round hole and make sure we use a lock washer and tighten the nut well!

author: hydrogen maser
author_rank: Regular Contributor
timestamp: December 19, 2016, 10:11:55 pm
content: Thanks Ed! I am aware of Greenlee, but I don't even look at them anymore because it will make my wallet scream in terror and go whimper in a corner. Perhaps I could build my own punch, no I idea how to do it but not knowing anything about a subject has never stopped me from trying before. Been watching machining videos on youtube for about a year now so that seems like I should be qualified to build a punchJust some round stock - grind off a flat spot - get a larger piece of stock for the other side and drill a hole in it - hit it with a 2lbs sledge - D hole created - easy enoughSmall alignment issue, but solvablePS: CS still works

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 19, 2016, 10:19:12 pm
content: Sounds like you need something like a Q-max screw-down punch. I know they do/did make D-Sub and IEC connector punches, not sure about flatted holeshttp://www.tooled-up.com/brandsubcat/q-max/punches/qma1/354/

author: hydrogen maser
author_rank: Regular Contributor
timestamp: December 19, 2016, 11:02:17 pm
content: Hmm, the Q-max appear to all be round hole (or not d-hole) but it might work - get one that has the hole clearance for the threads of a BNC (issue - each BNC manufacturer has multiple sizes of everything...) and grind off a flat spot on the punch and presto - D-Hole die, and not very expensive. Thanks!

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 20, 2016, 12:38:47 am
content: Quote from: hydrogen maser on December 19, 2016, 11:02:17 pmNot sure you could do that - you could grind off the punch but then you'd have a gap to the die so it wouldn't cut.

author: edpalmer42
author_rank: Super Contributor
timestamp: December 20, 2016, 01:10:53 am
content: AFAIK, all these punches are hardened steel. Grinding that would be a tedious process.

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: December 20, 2016, 05:50:55 am
content: You can buy tool steel stock from McMaster. Type O1 tool steel is sold in an annealed state, once machined it can be hardened by heating to 1400 F and quenching in oil. Other alloys are available that are water quenched or air-blast quenched.

author: hydrogen maser
author_rank: Regular Contributor
timestamp: December 20, 2016, 02:23:47 pm
content: Yeah, making my own punch and die is unlikely to succeed so, ebay to the rescue. Just ordered this ($10 on ebay): STRIPPIT PUNCH & DIE DOUBLE "D" .322'' X .377'' +.012'' 166S. This punch and die size should work for the BNC jacks I have. Will need a hand operated press setup. In looking at the cases I want to modify, they are all open in the back (no obstructions directly behind the places I want to punch holes, so I can mount the die on a piece of round stock and use a hand operated press. The hole size is pretty small so I should not need a huge amount of force and I think a hand operated press should work fine. We shall see.

author: edpalmer42
author_rank: Super Contributor
timestamp: December 20, 2016, 04:33:13 pm
content: I haven't seen those punches before. They look like they need a 'C' frame to align the two pieces. Do you have that?

author: hydrogen maser
author_rank: Regular Contributor
timestamp: December 20, 2016, 04:47:37 pm
content: Quote from: edpalmer42 on December 20, 2016, 04:33:13 pmNope. Going to wait until I get the die and take a look at it. There are C frames for these dies on ebay, but I'm not sure I need/want that and had something more like a vertical hand lever press in mind. I think I can make that work but I will decide what to do when I have the die and can look at it. Obviously these need pretty close alignment to work, that will likely be the biggest issue but I think that is solvable and not as hard as it might appear, got a few things in mind on how to do that. Making your own tools is half the fun

author: hydrogen maser
author_rank: Regular Contributor
timestamp: December 26, 2016, 02:54:04 pm
content: Ok, so I found at least one way to do this that is fairly quick and works. Drill a hole just large enough to clear the narrowest portion of the threads - either from the flat on a single D shaped threaded connector to the opposite round "face" or the two flats of a double d. Then use a sheet metal nibbler to make an oblong hole. It is not the prettiest looking hole but it is quick and works.

author: SeanB
author_rank: Super Contributor
timestamp: December 26, 2016, 04:48:44 pm
content: Die will probably have an ejector pin, so simply make a hole to clear it, and use this as an alignment point with the punch in the press and the die held firmly in the base, so you just put the ejector pin in the hole and press it through.

author: hydrogen maser
author_rank: Regular Contributor
timestamp: December 27, 2016, 09:09:27 pm
content: I got the punch and die and they are physically larger and heavier duty than I thought. It is the correct size - dropping the BNC connectors into the die - there is just a very small amount of rotation - should be perfect....but I'm not going to use it for anything at this point. Drill plus nibbler is working well and is fast so no need to build a press for the punch and die. Oh well, it was only $10 and perhaps I will find a use for it in the future. On this particular die there is no ejector pin the die is open on the bottom and the cut out metal just drops free - there are two alignment pins - one pin on the die and one on the punch. I am impressed with how heavy and well made the punch and die are.

author: technotronix
author_rank: Regular Contributor
timestamp: December 31, 2016, 11:29:53 am
content: Here I found the list of tools for BNC sheet metal "D" punch. This may help you to find suggested tool.http://www.mouser.com/Tools-Supplies/Tools/Punches-Dies/_/N-5gge