Metal Project Enclosures, Making Holes in Said Enclosures, Slicing Fingers, and

ElectricAye

Ladies and Gentlemen,

I don't even know where to begin whining about this....

Is it just me or does there seem to be something mind-booggling disparate about the incredible advances made in on-demand printed circuit manufacture, incredibly cheap access to miraculous technology like the Propeller, etc. and yet.... [noparse][[/noparse]he chokes back another scream of rage] here we are, cutting holes in sheet metal project boxes with tin snips and things like nibbler tools and metal splinters embedded in my fingers, in my clothes, in my carpet at home, in my children.... no doubt someday to be passed on to my children's children via their DNA...
I find making holes in sheet metal project boxes drives me crazy!
First, the off-the-shelf boxes cost too much. Why do they cost so much more than a cookie tin?
Second, the sheet metal seems too thin to work with. It's so skimpy, it can't take the force of drill bits without crinkling up, causing the drill bit to bind up, drift all around, etc. It creates an obscene amount of sharp edges that are always reaching out to slice my flesh. So that leads me to seek thicker metal, which costs a fortune. I see on the internet there are all sorts of various methods for creating holes - hole punches, hole nibblers, etc. but it all looks so much like what I'm doing already, which seems to dent and twist and scratch up the sheet metal so much, the end result looks horrible. And, call me a cheap cry baby, but I don't want to buy a whole rack of tools or a CNC just to deal with a problem like this.

I don't want to use plastic because I want the shielding that metal provides. Also, I want some protection from fire, and I don't know if plastic fits the bill.

I find myself jealously eyeing my son's Erector Set and wondering why prototype boxes can't be made with something similar - little angle pieces and modular panels that are pre-drilled, etc. for Din plugs, Pots, LEDs, etc. When you need a quick prototype that is rugged, functional and doesn't look like newly battered Smile, you just screw all these ready-made pieces together. And if you need to make a hole, you can work with a flat panel, rather than this 3 dimensional hunk of flimsy stuff you somehow have to clamp down and block up in a drill press and/or arbor press/punching stage, etc. [noparse][[/noparse]que primal scream]

In any case, I can't get over how incredibly advanced and accessible the electronic portion of product development has become while the world of connectors and project boxes remains one step away from the Stone Age.

Does anyone sell modular metal prototyping elements that would end my suffering? Or am I doomed to endure a lifetime of nibblers and metal splinters stuck forever in my genome?




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davejames

EA,

Your frustration is understood. I've slit & sliced and otherwise maimed myself a number of times, usually using the wrong tool for the wrong job.· And for all the blood-letting, the project still looks half-a##ed.

I've found two tools that have helped: 1) a "stepped" drill bit that has a number of preset hole sizes with one cutting edge, and 2) good ole Greenlee sheet metal punches. Neither are inexpensive, but they definitely are worth their weight.
Putting masking tape on the metal before attacking it with a nibbler really helps in preventing scuffing the clean edge of the hole.

As for lining up holes...I'm still struggling with that as my hand-held drill does drift a bit (or maybe it's me who's drifting!).


DJ

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Instead of:

"Those who can, do.· Those who can't, teach." (Shaw)
I prefer:
"Those who know, do.· Those who understand, teach." (Aristotle)


Post Edited (davejames) : 2/24/2009 5:38:25 AM GMT

Phil Pilgrim (PhiPi)

I hear your pain regarding three-dmensional boxes that are hard enough to fixture, let alone cut out. That's one reason I've always preferred boxes made from aluminum extrusions that use removeable flat panels, which can be made from anything: metal, laminates, plastic, etc. And if you screw up cutting a panel, you haven't ruined the whole box. As an example, check these guys out.

Also, when you're designing a circuit board, pick an enclosure first, then lay out the board to fit it. Too often, the enclosure is an afterthought; then it becomes an ordeal finding one to fit an already-designed board.

Another trick you can do, if your PCB fab does routering, is to design the panels alongside the PCB and have them all made at once. Just pick attractive soldermask and silkscreen colors and you'll have nice-looking pre-cut panels with the artwork and legends preprinted.

For larger lots of laminate cutouts, I highly recommend JMJ Profile. (Anyone who remembers Parallax's M&M sorter may recognize a couple of the parts on their homepage.)

-Phil

Post Edited (Phil Pilgrim (PhiPi)) : 2/23/2009 10:31:15 PM GMT

Ugha

You could always put a wood block on the inside of the box as your drilling into it. That's what I used to do for AC outlet boxes that weren't pre-stampped.

QuattroRS4

On the topic of enclosures - I work closely with a high volume plastics manufacturer .. I had played·with and discussed with the customer - the idea of a plastic protoboard enclosure (2mm wall thickness) with pcb standoffs & screws,cover, switch slot and power led 'light pipe'- with 'knock out' (thin walled section easily trimmed out) sections for all the standard accessory kit items .. KB,Mouse and VGA as well as extra 'Knock out' sections throughout the enclosure to facilitate customisations ... If there was enough interest in these (by enough I mean enough to convince me to foot the tooling fees) I would certainly do it.

Also if anyone has suggestions on how a plastic protoboard enclosure should look .. then by all means post them here. The idea would be to have a quality sub $10 protoboard enclosure.

Regards,
John Twomey

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'Necessity is the mother of invention'

Those who can, do.Those who can’t, teach.

ElectricAye

Hey,

First, thanks for the inputs. It's nice(?) to know I'm not the only one who has problems with this man vs. sheet metal thing.

Second, I know that there are makers of conductive plastics, but could such a thing be useful in actually shielding a circuit?

rjo_

Here, Here!!!

I love the concept of an erector set/tinker toy enclosure kit. Seems like that would be good for all kinds of stuff... bot bodies, board enclosures, high tech parts bin, etc. etc.

My problem with plastic is that at home, I only have a dremel to work with. For holes it is fine... but for cutting an edge, I end up melting my case rather than cutting it. I'm thinking about my dremel apart and either ruining it, so I have a good excuse to buy a variable speed unit... or successfully modifying it so that I can control the speed.

Quattro,

I am definitely interested.

kwinn

If you need shielding and a plastic enclosure would work if it could be shielded, then use aluminum tape inside the enclosure for shielding.

ElectricAye

Out of desperation, I searched the internet for ways to make metal cases for prototypes and I stumbled upon this company located in Canada:

www.protocase.com

You design the box yourself so it's custom made. I downloaded their free software and tinkered with it and it seems very intuitive. They claim they make boxes within a few days and have all sorts of nifty capabilities, silkscreening, etc. Problem is, the cost for a medium sized box would probably be about $180 to $220 US dollars for a single unit. That's pretty ouchy but prices per unit drop dramatically for more than one unit. Possibly most cost effective would be ordering their flat panels - it looks like you can get a single flat panel of about 3 inches by 12 inches perforated quite a bit for around $80. This is about what I spend in bandages and indulgences after working with sheet metal.

So anybody know anything about this company?

Oldbitcollector (Jeff)

rjo_ said...
Here, Here!!!

I love the concept of an erector set/tinker toy enclosure kit. Seems like that would be good for all kinds of stuff... bot bodies, board enclosures, high tech parts bin, etc. etc.

I collect erector-set pieces for this reason.

rjo_ said...

My problem with plastic is that at home, I only have a dremel to work with. For holes it is fine... but for cutting an edge, I end up melting my case rather than cutting it. I'm thinking about my dremel apart and either ruining it, so I have a good excuse to buy a variable speed unit... or successfully modifying it so that I can control the speed.

Seeing the exact same thing here.

I'm thinking about using a light dimmer switch with male/female 110v plugs to see if I can
slow mine down. Not sure if this will potentially damage the dremel, but I doubt it.

OBC

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potatohead

A rougher abrasive will help with the burning problem. So will short attempts, instead of a sustained attack on the material. I often use a piece of hard stainless steel, sheared with a burr on it for cleanup. When you apply that edge to plastic, the effect is a lot like a planer for wood. Nice, thin, long shavings.

It is better to work on very cold plastic when using a dremel.

What happens there is the cutting action on the mineral creates heat. The heat softens the plastic, and softer plastic tends to smudge as much as it does cut. This only worsens the problem! As soon as the plastic in near contact with the cutting surface of the dremel reaches that smudge temp, a flow starts, and that clogs the head, meaning plastic rubbing against plastic, and you are cooked! Game over.

A colder starting temp, plus a lower grit will both combine for better results. Also, obtaining one of those small, rubber cleaning tools is very valuable. Those work by softening the rubber, which then sticks to the material clogging the head, then the rubber sticks to the rubber also, pulling it away, leaving a very clean cutting surface. For abrasive type tools, using this can both extend the life of the abrasive, and give you an easy access to a fresh cutting surface on demand.

Edit: With plastics, it's a very good idea to apply the cleaning material right away. Do it regularly. Once the plastic has a chance to really set, you've ruined that abrasive head.

If you want to, the coarser grit, or more aggressive metal cutter, depending, can be used to rough out the hole. Just like step drilling, you then take smaller, smoother passes at the material, watching for heat / flow problems.

Pick up a set of cheap, small diamond and cutter files. These can be used to deal with corners, which are the hardest to do with a dremel type tool. Use the diamond on metals, the cutter type on plastic and wood.

Just put the plastic in the fridge for a while. Be careful about pressure you apply to it though! The cold makes it more brittle, which is more abrasive type dremel friendly, but that same brittle means a lot lower tolerance for stress.

For the drilling in metal problem, use a punch and a block! The punch can be most anything sharp. I generally use a simple nail. Setup the block and part to be drilled so that they are firm. Tap the punch into the material enough to make a nice cone shaped dent, or even a small hole.

The drill will center in the hole and not drift much at all.

For larger sizes, you need to step drill. This means doing a small pilot hole, say .125", then move up to .250" then .500", etc... It is completely possible to just drill a .250 and larger holes directly, but doing so requires more control force at the drill, a much more measured drilling movement, and a bit of luck! Higher drill speeds don't hurt either!

What happens is on thin metal, the first significant cut from the drill might end up more or less continuous. When this occurs, the drill is pulled downward, or the metal upward, both of which cause problems!

Step drilling avoids this by limiting the amount of material engaged by the drill at any one time.

Another approach is to pre-drill a block. Just run a hole right through it and set it aside. Then do your punch, and then sandwhich the material to be drilled BETWEEN the two blocks! Locate your punch center by lifting the block that contains the drill bit body, lower it again once the bit is centered in the pilot structure, then apply firm pressure to both blocks, and slow and steady downward pressure on the drill body. The resulting hole will be very, very clean, particularly at higher drill speeds. You want to use your muscles for resistance. Push down and pull up at the same time. Just make sure you push down a bit harder. What this does is sharply limit the drill motion, once the target material is pierced fully by the drill bit body. The danger area is right at the intersection of the conical surface of the drill bit, and the cyndrilical surface that forms most of it. As that edge leaves the target material, the amount of force required to keep drilling drops sharply!

At that point, if you are moving quickly, there is a serious chance of prolonged engagement between the cutting surface of the drill bit, and the material, and that ends up leaving a burr and or shearing or deforming the material. Not to mention, taking you off course with the drill body!

You can use a clamp to constrain the blocks too, if you want.

For drilling plastics, you need to essentially cut a pilot hole. Punching often adds stress to the process. Not good. One trick I use is the good old backup soldering iron. It's a melt, instead of a cut, but it really works! Just locate your hole center, and apply the iron quickly to form the small cone shaped centering structure you need, then step drill from there. If you use the blocks, you will get a near burr free hole in most any plastic. If you are step drilling you really only need the blocks for the final pass. Intermediate ones are no worries. Just use a backing block and don't worry about the block that would cover the drill body.

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Post Edited (potatohead) : 2/24/2009 6:05:19 PM GMT

Phil Pilgrim (PhiPi)

Speaking of step drilling, a Unibit is ideal for thin materials. Also, for the cleanest cuts, start with a #2 spot drill (a.k.a. center drill). And then, a hand deburring tool will clean up any rough edges.

BTW, a cheap benchtop drill press is always better for this kind of thing than a portable electric drill. Save your pennies for a good keyless chuck, though, and you'll have a nice setup. Finally, when drilling sheet metal, Vise Grips and a pair of heavy leather gardening gloves will save you many boxes of Band-Aids and, perhaps, a trip to the emergency room.

-Phil

potatohead

Totally agreed on the gloves. Always had mixed results with the grip. On one hand, it's good for constraining the material. On the other, it's a PITA to avoid cosmetics. I'll often just use a pin fixture. Rest the material against that, and drill away. Movement is counter clock-wise, so put the pin where it makes sense, and it does that work for you.

If working on wood, just a simple nail does the trick for that as well.

Damn! That unibit is sweet! I'll have that on my "when I can buy tools, buy it" list for sure. For years, I've just used a nice keyless speed chuck. No big deal to change bits.

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kelvin james

You could look at getting a small vertical mill for home metal working. There is some knowledge required to operate one properly, but nothing that hard to master. There may be some deals on ebay.


http://www.sherline.com/mills.htm

Carl Hayes

For some time now I've been using an old New Hermes Engravograph to make front panels, rear panels, etc.· I can make a template from any cheap material such as wood, up to seven times as large as the panel, and use it for precision engraving on the project itself.· I draw the template by any method (usually on a computer), print it on a label, stick the label on cheap wood or pressboard or something, cut it out with a band saw, clamp it to the engraving machine's table, mount the workpiece, and cut away.·

Here's a panel I made yesterday and today.· It's two layers of plastic (mounted in a metal panel).

The rear layer has just two round holes for the switches and one rectangular hole for the display, which is mounted to the rear side of the rear layer.· All three holes were cut with the engraving machine.

The front layer sticks flush through the hole in the metal, and has just the two holes for the switches and a transparent window for viewing the display.· The front surface is perfectly smooth.· The lettering was done by (1) painting the back side blue (with the window masked); (2) reverse-engraving the letters (that is, cutting mirror-image letters)·into the plastic, through the paint, for viewing through the plastic from the front side; and (3) painting the back side again, white, to fill the lettering.

For a metal panel, I would paint it, engrave the letters (and holes), then fill the grooves with a contrasting color paint.· Easy.

Not bad, I think, if I say so myself.· I'll never go back to cutting panel holes with a drill press, or using stick-on letters.· The engraver uses carbide cutters at about 14,000 rpm and will cut almost anything except hardened steel.· Such machines go on eBay for (sometimes) a couple hundred bucks, but sometimes more.· Mine was a gift from a friend who hadn't used it for twenty years.

Of course, it's also good for engraving plaques, trophies, and such.· I originally wanted it for making trophies for my Judo students.· But for DIY electronics it's the best thing going.

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· -- Carl, nn5i@arrl.net

Post Edited (Carl Hayes) : 2/24/2009 8:48:31 PM GMT

Twisted Pair

Good job Carl. Looks very professional. I like your method of assembly but since I have a machine shop complete with a nice compliment of sheet metal working equipment and tools, I make my own enclosures and of coarse out of various types of metal. I've just finished another enclosure and I have attached a few photo's. This project was for a friend and he wanted to have the old time look of analog equipment. I do all the design work on my computer. When I make enclosures for others, one of the first questions I ask is what are the internal dimensions required. Once I have that answer, the design process will begin. Most people will make the electronics first without regard to the enclosure requirements. What is available from retailers or custom metal fabrication shops is either not exactly what you need or simply cost an arm and·a leg. That is why I make my own. Having the right tools for making enclosures is the only way to go. It saves time and many cuts on the hands etc, and will produce nice looking enclosures.·The cost of these tools is not cheap but it is well worth the expense if you plan on making a lot of enclosures. Otherwise, you can simply find someone to make your enclosures for you without the cost of a high dollar metal fabrication shop.


TwistedPair....

Carl Hayes

Cool, Pair.· You make me wish I had a shear and a finger brake, at least.· I get my enclosures, usually, by buying old electronics at garage sales and making new front & rear panels.

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· -- Carl, nn5i@arrl.net

ElectricAye

Guys,

So where are all the hand carved granite enclosures? I have yet to see any of those posted yet.

You know you're all causing me to suffer Enclosure Envy here with all these fine looking photos. But what I'm dreaming about is either something prefab that just fits together like an Erector Set with standard sized and shaped ports for parts, pots, BNCs, LCDs, etc.... or an automated customized service that is as inexpensive and easy to use as, say, expressPCB, etc.

Hey, maybe Parallax could start a new product line???

Carl Hayes

ElectricAye said...
Guys,

So where are all the hand carved granite enclosures?

Gosh, Pair, we post pix of all this neat stuff, and is it appreciated?· No, it's taken for granite.

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· -- Carl, nn5i@arrl.net

Mike2545

As far as project boxes I have found these www.mierproducts.com/instrument_boxes.htm The BW-98 are 12.79 each plus shipping. They are 7"X8"X3.5: plenty big enough for a nice project. If you e-mail them they will sell to hobbyists.

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Mike2545

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Twisted Pair

Yeah, I know what you mean Carl. Guess we had nothing rock solid to contribute....

ElectricAye, I can visualize your idea of an erector set type enclosure with removable panels with the cutouts for the hardware. The cost probably wouldn't be to bad but to keep everyone happy regarding the panel with cutouts, you would have to have many panels on hand and even then, not everyone would be happy with the selection. So back to custom made enclosures. You know that craftsman who do this kind of work is a rare breed. Like Carl, I enjoy what I do, thats why I do it.

Maybe I can help you out with your project. Got the internal dimensions or a drawing ?

TwistedPair....

Carl Hayes

Twisted Pair said...
Yeah, I know what you mean Carl. Guess we had nothing rock solid to contribute....

No resepct at all.· Sometimes it's absolutely petrifying to contemplate.

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· -- Carl, nn5i@arrl.net

Phil Pilgrim (PhiPi)

ElectricAye said...
I don't want to use plastic because I want the shielding that metal provides. Also, I want some protection from fire, and I don't know if plastic fits the bill.

PCBs are made of copper-plated (good shielding material) FR4 glass-epoxy laminate. The "FR" stands for "fire-retardant".

ElectricAye said...
...or an automated customized service that is as inexpensive and easy to use as, say, expressPCB, etc.

Again, why not let the PCB fab do your panels, too? Okay, the tricky part is finding one to do interior routering for the bargain prices. If this proves impossible, you can at least design in small holes as perforations for the cutout outlines and do the knockouts and edge dressing yourself.

-Phil

Carl Hayes

I've seen ads (in N&V or maybe Elektor) for a house that makes panels in much the same way as PCB houses make PC boards.· I haven't tried them, but the pix in their ads are pretty.

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· -- Carl, nn5i@arrl.net

ElectricAye

Twisted Pair said...
...
Maybe I can help you out with your project. Got the internal dimensions or a drawing ?

Twisted,
I appreciate your offer but mine is more of a systemic problem than a specific design. The project that I'm working on now has me building devices, testing the approach, then redesigning and trying new tests as fast as possible. Designs, therefore, are practically disposable. Since the people I'm working for don't really know what they're looking for in their experiments, my process has become a big iterative loop de poop. So it kills me to come up against this Stone Age sheet metal thing after whizzing through so much else. That's why I like the idea of the Erector Set approach and I'm surprised there isn't such a thing apparently. I know there are lots of different connectors, etc. out there, but to have a standard stock of SOMETHING would be better than what's (un)available now. I don't have time for making handcrafted works of art - in fact, a few times I've even used heavy duty foil and baking tins to house things and, well, the lab sometimes looks like a Jiffy Pop commercial sans popcorn. It annoys me that the rate limiting factor for running through these experiments turns out to be a housing crisis.

Twisted Pair

Roger that ElectricAye. Sounds like you have your hands full. Just to let you know, I was offering more than just sheet metal enclosure help. I also have the tooling for plastic enclosures. Injection molding and Vacuum forming capabilities.


TwistedPair....

Carl Hayes

Wow, Pair -- that's a gneiss offer, nothing to lava bout.

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· -- Carl, nn5i@arrl.net

Mike2545

Here is a guy in Cleveland that will custom make an aluminum box.

cgi.ebay.com/ALUMINUM-PROJECT-BOX-I-MAKE-THEM-TO-YOUR-SIZE-EMAIL-ME_W0QQitemZ200316773056QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item200316773056&_trksid=p3286.c0.m14&_trkparms=72%3A1205|66%3A2|65%3A12|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A50

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Mike2545

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sam_sam_sam

Mike2545

Have you ever use them before

Are they any good




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··Thanks for any··that you may have and all of your time finding them

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Sam

Mike2545

No I can't speak from experience, I found them surfing around looking for project boxes to help someone else in another forum. They look well made and the price is right.

When I have a need for an aluminum box I'll probably give them a try. If you beat me to it let me know what you think.

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Mike2545

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