[TowerTalk] N-connector double-D punch

[Jim Lux]

I assume you're looking for a punch that is .641 diameter, with 0.546 across the flats (that's what's in the Amphenol catalog)..

Indeed, Greenlee doesn't appear to have ones small enough (at least, according to the Mouser catalog)

http://www.bromac.biz/sizes.htm has one that's pretty close.. BMP-8DD, 0.635 diameter and 0.540 across the flats.. slightly smaller than what Amphenol recommends, but since the connector is actually 0.531 across the flats, it might work.  

BUT, for $170, you could probably find another way to solve the problem.
http://www.buckeyeshapeform.com/buckeye-enclosures/pdf/DoubleDpunchlist.pdf also has exactly the size you need.
I don't think they actually sell the punch, it's just a stock hole size for them.

frontpanelexpress...  a 12"x12" aluminum panel 3mm (0.118") thick with 9 doubleD holes to the Amphenol dimnesions is $42.82 without shipping.  The holes cost $0.61 each

-----Original Message-----
>From: "Michael E Fox (N6MEF)" <n6mef at mefox.org>
>Sent: Oct 15, 2008 2:59 PM
>To: "'Roger (K8RI)'" <K8RI-on-TowerTalk at tm.net>, hinrgdj1 at comcast.net
>Cc: towertalk at contesting.com
>Subject: Re: [TowerTalk] N-connector double-D punch
>
>Wow.  I'd never heard of those.  Looks pretty cool.  Thanks for the link.  I
>can use that for another project.
>
>For this application, however, the hole isn't round.  A double-D punch
>produces a hole that is flat on two sides.  The connector is also flat on
>two sides and is, therefore, prevented from spinning in the hole.
>
>73,
>Michael - N6MEF
>
>-----Original Message-----
>From: Roger (K8RI) [mailto:K8RI-on-TowerTalk at tm.net] 
>Sent: Wednesday, October 15, 2008 2:00 PM
>To: hinrgdj1 at comcast.net
>Cc: Michael E Fox (N6MEF); towertalk at contesting.com
>Subject: Re: [TowerTalk] N-connector double-D punch
>
>hinrgdj1 at comcast.net wrote:
>> An annular cutter is quicker and smoother...
>>
>> http://www.blairequipment.com/Rotabroach_Cutters/rota_cutters.html
>>
>> A small fractional set can be had on Epay for ~$70...very handy shop tool!
>>
>>   
>I had forgotten about those.  They do an excellent job, work better than 
>a hole saw, give a professional looking cut even when used with a hand 
>drill (if the arbor fits the hole, or is self drilling)
>
>However in their comparison photo the drill hole will look far better if 
>they start with a small pilot hole and then work up. It will come out 
>"round" and with only a small burr.  Admittedly that takes a lot longer 
>and much more care, but it works if you don't have a broach on hand, or 
>don't want to wait for one to be delivered.
>
>73
>
>Roger (K8RI)
>> Mike K4EAR
>>
>>  -------------- Original message ----------------------
>> From: "Roger (K8RI)" <K8RI-on-TowerTalk at tm.net>
>>   
>>> Michael E Fox (N6MEF) wrote:
>>>     
>>>> I'm looking for what's called a "double-D" punch that is the correct
>size
>>>> for N-type connectors.  This will be used to punch holes in bulkheads
>for
>>>> installing either PolyPhaser DSXL lightening arrestors or N-type
>Amphenol
>>>> bulkhead pass-through connectors.
>>>>   
>>>>       
>>> I normally use Greenlee "knockout punches". The latest style split the 
>>> piece knocked out into two haves that look like the letter "D", but I've 
>>> never seen them called "double D". 
>>>
>>> OTOH material for bulkheads is normally thick enough I just use a drill 
>>> bit of the proper size, be it in steel or aluminum.  IOW it's a rather 
>>> small hole and punches for that size use a relatively small through bolt 
>>> (bout 1/4" to 5/16") that can be broken trying to punch holes in 1/8" to 
>>> 1/4" thick, Aluminum, Copper, or steel. I've busted the bolts on chassis 
>>> punches for tube sockets, let alone this size and thickness.  Drill the 
>>> hole undersize, then work up to the proper size one drill at a time. 
>>> This gives a hole with relatively clean and smooth sides however don't 
>>> forget to debur the inside and outside. BTW the hole for the through 
>>> bolt on most of the punches is as large or larger than the bulkhead 
>>> connectors for N or UHF.  (Same size IIRC)
>>>
>>> 73
>>>
>>> Roger (K8RI)
>>>     
>>>>  
>>>>
>>>> Greenlee doesn't make a double-D that is small enough and I'm having
>>>> difficulty finding the right size anywhere.  
>>>>
>>>>  
>>>>
>>>> This must exist somewhere.  Anyone know where to find one?
>>>>
>>>>  
>>>>
>>>> FYI - if you don't know what I'm talking about, then Google "double-d
>>>> punch".  You will find many out there, most notably Greenlee.  But I
>haven't
>>>> found any that have the right dimensions for a standard N-connector. 
>>>>
>>>>  
>>>>
>>>> Regards,
>>>>
>>>> Michael  /  N6MEF
>>>>
>>>>  
>>>>
>>>>  
>>>>
>>>>  
>>>>
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