Cut slot in metal enclosure door for ribbon keypad ?

die

ted properly in a press).

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.

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.

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.

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

snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

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.

On Saturday, October 19, 2019 at 12:03:00 PM UTC-4, snipped-for-privacy@gmail.com wrote :

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 .

e die

uated properly in a press).

similar to the D-sub hold punch that Martin mentioned earlier. This one c uts just a thin slot with no D-shape to it. (Thin being defined here as 13 mm x 41mm, IIRC?) Bigger than required, but I guess you need that minimum width to accommodate a suitably strong pull bolt.

hat some reviewers say because maybe they don't know what they're doing. P lus, 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? (w hich, we could live with, after touch-up). I'll report back on the results .

gh maybe the minimum by-hand?). Second, if the knockout punch approach can only do say.. 10 cabinets before it dulls, or breaks, that's not cost-effe ctive.

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.

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.

a common sized circular saw blade is a mighty big tool for a 19mm? slot

MA-4 enclosure, through which, we will route a 12-conductor ribbon cable (m embrane keypad).

et just says steel). It's a Hammond Manufacturing EJ1084 standard cabinet . with some effort, I believe the door can be removed? TBD.

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.)

nd die, and cut the whole thing at once. (Slot perimeter = about 92mm).

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.

before powder-coating. We just don't have the option to do that this time around.

Why not make a larger, round hole and use a custom piece to fit your cable? I guess that is a bit of work, but you are only doing this for a few unit s, no?

I think I would just have Hammond do the mods. Talk to them and let them p roduce the drawings from your needs. They can better figure out how to do it most cost effectively with a good result. You are going to need to do t his sooner or later.

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.

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

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

te:

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.

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

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

Michael Terrell wrote in news: snipped-for-privacy@googlegroups.com:

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.

mandag den 21. oktober 2019 kl. 15.55.24 UTC+2 skrev snipped-for-privacy@decadence.org:

you cannot use diamond to cut ferrous metal, they react and burn up the diamond

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

Lasse Langwadt Christensen wrote in news: snipped-for-privacy@googlegroups.com:

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

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.

mandag den 21. oktober 2019 kl. 18.40.27 UTC+2 skrev snipped-for-privacy@decadence.org:

"The diamond thing works but is expensive." "The tiny 'concrete saw' type abrasive cut-off wheels"

Lasse Langwadt Christensen wrote in news: snipped-for-privacy@googlegroups.com:

The diamond thing *HE* suggested.

Damn, you are thick.

Which is NOT the diamond wheel.

you can, but not a good choice.

I wanted to follow-up with the results using the "CP-6" punch from Omega: In a word... "barely". In two words... "not recommended"

Link:

We cut (5) cabinets before the threads on the pull bolt got so worn, we wor ried about bricking the tool.

So, we added (3) dock washers to the bolt end so that we're turning on diff erent threads. That bought us another (5) cabinets cut. And again, we ris k bricking the tool.

Five cabinet cuts is about all you can do without implementing workarounds. And at 10 cabinets, you need a new pull bolt. The die itself seems to b e OK, and not showing obvious signs of wear. However, you have to make abs olutely certain things are perfectly lined-up. Any "slop" and you risk bre aking the die by having it try to cut itself in the corners.

I don't know if spare bolts are available. (?) The pull bolt is special-keyed with a slot and pin, so an ordinary bolt won 't substitute.

Also, it takes incredible force to make the cut. You must bolt down the wo rk piece, and use at least an 18"-long (24" better) breaker bar to turn the bolt once it bites, even when it's lubed like crazy. In short, I don't be lieve this punch is truly rated for 16-ga steel. It may cut it a few times , but tool life is extremely short.

I will say: The rectangular hole left by this punch (even as difficult as it is to accomplish), is at least acceptable. The cabinet door did not def orm, as I half-expected it to do. The end result is reasonably flat surfac e, with a nice rectangular hole in it.

The only good news is that the immediate job is done. Any future orders and I'll have the cabinet vendor prep the boxes with the hole already cut before powder-coating, and we won't have to mess with it a t all.

In retrospect: I am wondering if we should have taken the time in design t o cut down on the width of the ribbon cable? For example, if we had multip lexed the LED's and switches on the keypad, we could have reduced the numbe r of conductors needed, and thus the overall width of the ribbon cable. Ma ybe 20%-25%? Doesn't seem like much until you have to get the breaker bar !

Anyway - if someone from the future stumbles upon this post, in similar nee d, you have your answers.

Friction on the threads is the problem. It's possible to adapt it to a hydraulic puller (threads don't turn during the pull, only to attach the pullhead).

P_DPP_RHS_RHP_RS.pdf

orried about bricking the tool.

fferent threads. That bought us another (5) cabinets cut. And again, we r isk bricking the tool.

s. And at 10 cabinets, you need a new pull bolt. The die itself seems to be OK, and not showing obvious signs of wear. However, you have to make a bsolutely certain things are perfectly lined-up. Any "slop" and you risk b reaking the die by having it try to cut itself in the corners.

on't substitute.

use the bolt for alignment only and use a press for the heavy work?

Agreed, friction is the problem (even when generously lubed). This punch & die doesn't come with a bearing (which I thought was a little weird that it didn't?)

I also thought about converting it to hydraulic, but the keyed bolt is also what aligns the bottom half of the die. But that said, as long as you can align the two halves, hydraulic should work.

P_DPP_RHS_RHP_RS.pdf

orried about bricking the tool.

fferent threads. That bought us another (5) cabinets cut. And again, we r isk bricking the tool.

s. And at 10 cabinets, you need a new pull bolt. The die itself seems to be OK, and not showing obvious signs of wear. However, you have to make a bsolutely certain things are perfectly lined-up. Any "slop" and you risk b reaking the die by having it try to cut itself in the corners.

on't substitute.

work piece, and use at least an 18"-long (24" better) breaker bar to turn t he bolt once it bites, even when it's lubed like crazy. In short, I don't believe this punch is truly rated for 16-ga steel. It may cut it a few tim es, but tool life is extremely short.

s it is to accomplish), is at least acceptable. The cabinet door did not d eform, as I half-expected it to do. The end result is reasonably flat surf ace, with a nice rectangular hole in it.

e hole already cut before powder-coating, and we won't have to mess with it at all.

to cut down on the width of the ribbon cable? For example, if we had mult iplexed the LED's and switches on the keypad, we could have reduced the num ber of conductors needed, and thus the overall width of the ribbon cable. Maybe 20%-25%? Doesn't seem like much until you have to get the breaker b ar!

eed, you have your answers.

Did you use cutting oil with the punch, and oil the threads to reduce the d rive friction??