Cut slot in metal enclosure door for ribbon keypad ?

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We need to cut an acceptable-looking slot in the front door of a metal NEMA
-4 enclosure, through which, we will route a 12-conductor ribbon cable (mem
brane keypad).

The enclosure is 16-gauge steel.  (Mild steel, I think?, but the data sheet
 just says steel).   It's a Hammond Manufacturing EJ1084 standard cabinet.  
 with some effort, I believe the door can be removed?  TBD.

Anybody got any ideas?
It's already powder-coated from the manufacturer, and I'd rather not damage
 the finish if it can be helped.  The keypad will cover any cosmetic damage
 on the front, so the concern would be the inside of the door.  (And not ag
ainst repairing the inside finish, so long as it would look OK.)

I'm thinking of using a 10-ton hydraulic press with a rectangular punch and
 die, and cut the whole thing at once.  (Slot perimeter = about 92mm).

I realize SED isn't a metal working forum, but you folks are into all manne
r of ideas (some wackier than others).  So, my advance apologies for postin
g here, but I'm hoping to get some good advice I can pass along to the folk
s who will have to do this.   We're looking at roughly 50-75 cabinets initi
ally.  

If follow-on orders flow in, we'll have Hammond, or whomever, punch them be
fore powder-coating.  We just don't have the option to do that this time ar
ound.

Thanks!

Re: Cut slot in metal enclosure door for ribbon keypad ?
fredag den 18. oktober 2019 kl. 02.44.08 UTC+2 skrev mpm:
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MA-4 enclosure, through which, we will route a 12-conductor ribbon cable (m
embrane keypad).
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et just says steel).   It's a Hammond Manufacturing EJ1084 standard cabinet
.  with some effort, I believe the door can be removed?  TBD.
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ge the finish if it can be helped.  The keypad will cover any cosmetic dama
ge on the front, so the concern would be the inside of the door.  (And not  
against repairing the inside finish, so long as it would look OK.)
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nd die, and cut the whole thing at once.  (Slot perimeter = about 92mm).
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ner of ideas (some wackier than others).  So, my advance apologies for post
ing here, but I'm hoping to get some good advice I can pass along to the fo
lks who will have to do this.   We're looking at roughly 50-75 cabinets ini
tially.  
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before powder-coating.  We just don't have the option to do that this time  
around.
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clamp a template to the front and use a router with a guide bushing?

a 1/8 inch carbide bit shouldn't have a much of problem with a bit of steel


Re: Cut slot in metal enclosure door for ribbon keypad ?
On Thursday, October 17, 2019 at 8:58:48 PM UTC-4, Lasse Langwadt Christensen wrote:
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Humm... I wonder. (?)
I thought the heat might be a problem with the powder-coat finish (inside door).
Might be worth trying.  (We might even own a router?)




Re: Cut slot in metal enclosure door for ribbon keypad ?
fredag den 18. oktober 2019 kl. 04.14.03 UTC+2 skrev mpm:
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you should be cutting the steel not melting it ;)

how big a slot do you need?

Re: Cut slot in metal enclosure door for ribbon keypad ?

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READ.  He said "12 conductor ribbon cable".

  Don't see many fashioned from welding cable, so I would say it is  
likely one of the 22 or 24 or 26 Gauge versions. Slot for the #22 and  
no worries.
  If there is enough room behind the cover piece, one could us a  
round hole and make the flat cable into a round one and pass that  
thru.  It makes a bigger 'knot like' exit though, so space is needed  
in the ingress and egress areas.

Re: Cut slot in metal enclosure door for ribbon keypad ?
wrote:

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Greenlee punch #229 , 9pin Dsub.

Cheers

Re: Cut slot in metal enclosure door for ribbon keypad ?
On Thursday, October 17, 2019 at 9:27:54 PM UTC-4, Martin Riddle wrote:
  
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Good idea, and was actually mentioned today on the shop floor.
We actually have one, but it is broken (not on this job) and nobody replaced it.
I'm not real keen on a D-Sub hole shape, (as opposed to a slot), but I guess it would work.

Re: Cut slot in metal enclosure door for ribbon keypad ?

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  Well then two siamesed round holes with a chamfer to knock the edge  
off would work.

  If it is a small enclosure you may not even be able to get the die  
in there.

Re: Cut slot in metal enclosure door for ribbon keypad ?
On Friday, October 18, 2019 at 9:02:54 AM UTC-4, DecadentLinux...@decadence
.org wrote:
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e  
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Thanks.  I wondered about that (whether the enclosure door could be situate
d properly in a press).
Clearly, I know just enough about mechanical to be dangerous.  :)

The shop guys found a knock-out punch on McMaster-Carr that might work, sim
ilar to the D-sub hold punch that Martin mentioned earlier.  This one cuts  
just a thin slot with no D-shape to it.  (Thin being defined here as 13mm x
 41mm, IIRC?)  Bigger than required, but I guess you need that minimum widt
h to accommodate a suitably strong pull bolt.  

Several of the reviews for this particular knockout punch, when used on 14-
ga steel, said it broke on the first use.

So, I'm concerned about it - but then I have also learned to discount what  
some reviewers say because maybe they don't know what they're doing.  Plus,
 our application is for 16-ga, not 14.  Another concern I have is that the  
knockout punch might chip the powdercoat on the inside door finish?  (which
, we could live with, after touch-up).  I'll report back on the results.  

I'm not sure the approach is viable long term.  First, it's labor (though m
aybe the minimum by-hand?).  Second, if the knockout punch approach can onl
y do say.. 10 cabinets before it dulls, or breaks, that's not cost-effectiv
e.

And third, the Hammond Mnfg. EJ1084 cabinet says it's 16-ga steel (and I'm  
sure it is...), but it sure feels heftier than that when you get it in your
 hands and compare it to a known sample of 16-ga steel.  


Re: Cut slot in metal enclosure door for ribbon keypad ?
On Saturday, 19 October 2019 15:36:31 UTC+1, mpm  wrote:
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ce.org wrote:
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die  
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ted properly in a press).
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imilar to the D-sub hold punch that Martin mentioned earlier.  This one cut
s just a thin slot with no D-shape to it.  (Thin being defined here as 13mm
 x 41mm, IIRC?)  Bigger than required, but I guess you need that minimum wi
dth to accommodate a suitably strong pull bolt.  
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4-ga steel, said it broke on the first use.
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t some reviewers say because maybe they don't know what they're doing.  Plu
s, our application is for 16-ga, not 14.  Another concern I have is that th
e knockout punch might chip the powdercoat on the inside door finish?  (whi
ch, we could live with, after touch-up).  I'll report back on the results.
  
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 maybe the minimum by-hand?).  Second, if the knockout punch approach can o
nly do say.. 10 cabinets before it dulls, or breaks, that's not cost-effect
ive.
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m sure it is...), but it sure feels heftier than that when you get it in yo
ur hands and compare it to a known sample of 16-ga steel.

What's the big problem with using a mounted circ saw, eg cutoff saw or comp
ound mitre saw? If it's heat, go slower & use lube. Other options have thei
r upsides, but this one is as difficult as falling off a log. All methods a
re either going to chip the coating or have other significant issues.


NT

Re: Cut slot in metal enclosure door for ribbon keypad ?
snipped-for-privacy@gmail.com wrote in

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  The dremel tool with 1.5 inch cut off wheel is the best, least  
damaging option.  Done right the chipping (if any) would be less than a  
mm.  It is abrasive as opposed to a cutting tool, and it plunge cuts  
almost to the exact length he needs for a 12 conductor flat cable.  

Re: Cut slot in metal enclosure door for ribbon keypad ?
On Saturday, 19 October 2019 18:06:20 UTC+1, snipped-for-privacy@decadence.org  wrote:
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My experience with those has not been too good for that sort of task. Perhaps you've found a way to make them work well. I would never suggest that for production.


NT

Re: Cut slot in metal enclosure door for ribbon keypad ?
:
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mpound mitre saw? If it's heat, go slower & use lube. Other options have th
eir upsides, but this one is as difficult as falling off a log. All methods
 are either going to chip the coating or have other significant issues.

We did the first 10 cabinets this way (chop saw).
The first was horrible, as the blade was dull.
New blade, next (9) results were OK, but it really doesn't work as well as  
you might expect.  The other methods mentioned will make a much neater hole
.

Re: Cut slot in metal enclosure door for ribbon keypad ?
On Saturday, 19 October 2019 18:11:59 UTC+1, mpm  wrote:
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compound mitre saw? If it's heat, go slower & use lube. Other options have  
their upsides, but this one is as difficult as falling off a log. All metho
ds are either going to chip the coating or have other significant issues.
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s you might expect.  The other methods mentioned will make a much neater ho
le.

It works the same as I expect. I know that because I've used the method. Ne
ater hole is what you want. FWIW you can improve the hole by flipping the s
heet over & finishing the cut off from the other side. Whether that gives y
ou enough neatness I couldn't say, it's certainly not perfect.  

For a perfect edge you could try water jet cutting - I would be unsurprised
 if it attacked the powder coat though. There is no ideal option.


NT

Re: Cut slot in metal enclosure door for ribbon keypad ?
On Saturday, October 19, 2019 at 1:11:59 PM UTC-4, mpm wrote:
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te:
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compound mitre saw? If it's heat, go slower & use lube. Other options have  
their upsides, but this one is as difficult as falling off a log. All metho
ds are either going to chip the coating or have other significant issues.
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s you might expect.  The other methods mentioned will make a much neater ho
le.

What kind of blade are you using? this is a 4.5" Diamond, Metal cutting bla
de for under $20

<https://www.grainger.com/category/tools/saw-blades/diamond-saw-blades?attr
s=Blade+Dia.%7C4-1%2F2%22~~Primary+Saw+Application%7CMetal&filters=attr
s>

Have you asked for help on the news:rec.crafts.metalworking newsgroup?

https://groups.google.com/forum /#!forum/rec.crafts.metalworking

Re: Cut slot in metal enclosure door for ribbon keypad ?

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  Dremel toothed cutting wheels are NOT made for anything harder than  
brass or copper.  The diamond thing works but is expensive.

  The tiny 'concrete saw' type abrasive cut-off wheels are ideal for  
this as they only 'cut' where the user abrades the surface with the  
edge of the wheel and the faces do a bit of it as well.  In a plunge  
cut scenario, they continue to 'cut' on the edge of the wheel, AND  
abrade the side walls as well, thereby curtailing any binding.  With  
proper starter holes at either end, it even makes for perpendicular  
ends on the slot.

  They are also cheaper.  And the final point is that a 12 conductor  
ribbon is not anywhere close to 4.5" in length so cutting a slot with  
such a large diameter tool, is simply the wrong choice from the get-
go.

Re: Cut slot in metal enclosure door for ribbon keypad ?
mandag den 21. oktober 2019 kl. 15.55.24 UTC+2 skrev snipped-for-privacy@decadence.org:
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you cannot use diamond to cut ferrous metal, they react and burn up the diamond

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agree, and if you managed to cut the tiny slot the edges would be very sharp since the disc would barely go through the sheet

Re: Cut slot in metal enclosure door for ribbon keypad ?

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  I did not suggest diamond, ya ditz.  Respond to the post of the  
person that did.


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  Dressing any sharp edges after the slot is made would be easy.

  I have done this stuff before, and I know how to pass a 'plastic'  
insulated conductor or conductor array through a sheet metal slot  
without cutting into it.  Chamfers and rounds and fillets have been  
in my mind for decades.  Even tiny ones.

Re: Cut slot in metal enclosure door for ribbon keypad ?
mandag den 21. oktober 2019 kl. 18.40.27 UTC+2 skrev snipped-for-privacy@decadence.org:
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"The diamond thing works but is expensive."
"The tiny 'concrete saw' type abrasive cut-off wheels"

Re: Cut slot in metal enclosure door for ribbon keypad ?

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  The diamond thing *HE* suggested.

  Damn, you are thick.

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  Which is NOT the diamond wheel.  


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