Homebrew_PCBs

I'm tackling the building of the EDM device I mentioned in an earlier
post. Ordering most of the electronics parts today. But. . . .

The enclosure (12"x12"5" minimum needed for heat dispersal) is to be
built from sheet steel or aluminum (1/16"). The author presents three
methods of building the enclosure; I'd like to do what he did, use
aluminum brackets (L-shaped) to join together aluminum pieces --
sides, ends, floor, cover.

I'm hoping someone here might have built a similar enclosure and might
provide advice about how to join all the aluminum pieces together . .
. drill holes, nuts and bolts the only way? Thought there might be
some sort of space-age adhesive that might work.

Thought I might try to scrounge up an old metal computer enclosure, too.

Thanks for the help,

Brian

Brian Chapman
Evansdale, Iowa



---

On Sun, 03 Jul 2005 18:45:29 +0200, Brian Chapman
<cornbeltroute@...> wrote:

> I'm tackling the building of the EDM device I mentioned in an earlier
> post. Ordering most of the electronics parts today. But. . . .
> The enclosure (12"x12"5" minimum needed for heat dispersal) is to be
> built from sheet steel or aluminum (1/16"). The author presents three
> methods of building the enclosure; I'd like to do what he did, use
> aluminum brackets (L-shaped) to join together aluminum pieces --
> sides, ends, floor, cover.
> I'm hoping someone here might have built a similar enclosure and might
> provide advice about how to join all the aluminum pieces together . .
> . drill holes, nuts and bolts the only way? Thought there might be
> some sort of space-age adhesive that might work.
> Thought I might try to scrounge up an old metal computer enclosure, too.
> Thanks for the help,
> Brian
> Brian Chapman
> Evansdale, Iowa

I've never build large enclosures, as i usually re-use old stuff, but for
small enclosures the following works well:

Bend two pieces of aluminum to a C shape, the one piece forms top and
sides, the other piece forms bottom and front/back.For a larger enclosure
you probably want to use brackets or bent back "ears" on front/back/bottom
to screw things together.
The top piece is slightly larger and the two are just slipped together,
rotated 90 degrees.

Other than that, i think you can't really do anything wrong here no matter
how you make the enclosure.

Gluing wouldn't allow easy disassembly, but epoxy holds well on metals
(maybe to glue brackets on one side). I'd prefer screws and rivets. Don't
try brazing/welding aluminum unless you have a tig welder.

ST

> Bend two pieces of aluminum to a C shape, the one piece forms top

and sides, the other piece forms bottom and front/back. <

This was one of the three methods the author suggests for building an
enclosure. Thought it would require a bending brake, though, to make
it fit together fairly well?

> I'd prefer screws and rivets. Don't try brazing/welding aluminum

unless you have a tig welder. -ST <

Screws/rivets it is, then. Thanks for the help, ST. Appreciate it.

Brian Chapman
Evansdale, Iowa


---

Hi Brian, if at the hardware store, look for "Pop" rivets which are a
blind rivet system - Pretty cheap, easy to work with too.





--- In Homebrew_PCBs@yahoogroups.com, "Brian Chapman"
<cornbeltroute@m...> wrote:

> > Bend two pieces of aluminum to a C shape, the one piece forms top
> and sides, the other piece forms bottom and front/back. <
>
> This was one of the three methods the author suggests for building an
> enclosure. Thought it would require a bending brake, though, to make
> it fit together fairly well?
>
> > I'd prefer screws and rivets. Don't try brazing/welding aluminum
> unless you have a tig welder. -ST <
>
> Screws/rivets it is, then. Thanks for the help, ST. Appreciate it.
>
> Brian Chapman
> Evansdale, Iowa
>
>
> ---

On Sun, 03 Jul 2005 19:11:02 +0200, Brian Chapman
<cornbeltroute@...> wrote:

>
> This was one of the three methods the author suggests for building an
> enclosure. Thought it would require a bending brake, though, to make
> it fit together fairly well?

Yea for a large one i suppose. For the smaller ones i built a vice was OK
(no more than 15 cm any side.)

You could probably bend a larger one with hardwood pieces or steel angles,
clamps, and a lot of patience.
In the files is a picture of a simple homeade bending brake which i want
to build for ages.

Maybe use brackets of aluminum channel along the edges (outside) and
straight plates. (Kind of like a aluminum suitcase), but still doesn't
look as good as bent IMO.

As Chris suggested pop rivets are great, use them for the permanent
connections (you need to drill them out to remove) and screws for the lid
etc.

ST

Chris, ST, all great ideas. Again, I thank you.

ST, just a side note: This list, imho, would not be so vital, so
energetic, if you did not participate here. I am the rawest of newbies
in so many areas, yet you've always been generous with your time,
answering many of my questions here.

-Brian

Brian Chapman
Evansdale, Iowa


---

In article <op.stcj8lxvmg0lsf@tu-x2pj5qeyp2u4>,
Stefan Trethan <stefan_trethan@...> wrote:

> I've never build large enclosures, as i usually re-use old stuff, but
> for small enclosures the following works well:

> Bend two pieces of aluminum to a C shape, the one piece forms top and
> sides, the other piece forms bottom and front/back.For a larger
> enclosure you probably want to use brackets or bent back "ears" on
> front/back/bottom to screw things together. The top piece is slightly
> larger and the two are just slipped together, rotated 90 degrees.

Sounds similar to the methods I use - 1/4"x1/4" Al along the "seams" and
drill and tap 6BA (6BA tapping is 2.3mm so probably similar to M2.5) to
screw the sheet to the square.

With larger with heavier contents enclosures use larger "square" and
screws (4BA - M3.5) or 1/2"x1/2"x1/8" Al angle.

Sometimes, of course, it is neccessary to have individual flat panels but
the joining method above works just as well for those.

Hi,

I'm interested in this way of building enclosures. Can you post some
pictures? An how do you bend the AL and make straight and nice looking
corners?

Thanks,

Joe

-----Original Message-----
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of lists
Sent: maandag 12 september 2005 20:27
To: Homebrew_PCBs@yahoogroups.com
Subject: Re: [Homebrew_PCBs] EDM enclosure -- suggestions?

In article <op.stcj8lxvmg0lsf@tu-x2pj5qeyp2u4>,
Stefan Trethan <stefan_trethan@...> wrote:

> I've never build large enclosures, as i usually re-use old stuff, but
> for small enclosures the following works well:

> Bend two pieces of aluminum to a C shape, the one piece forms top and
> sides, the other piece forms bottom and front/back.For a larger
> enclosure you probably want to use brackets or bent back "ears" on
> front/back/bottom to screw things together. The top piece is slightly
> larger and the two are just slipped together, rotated 90 degrees.

Sounds similar to the methods I use - 1/4"x1/4" Al along the "seams" and
drill and tap 6BA (6BA tapping is 2.3mm so probably similar to M2.5) to
screw the sheet to the square.

With larger with heavier contents enclosures use larger "square" and
screws (4BA - M3.5) or 1/2"x1/2"x1/8" Al angle.

Sometimes, of course, it is neccessary to have individual flat panels but
the joining method above works just as well for those.




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On Mon, 12 Sep 2005 20:26:48 +0200, lists
<stuart.winsor.lists@...> wrote:

> Sounds similar to the methods I use - 1/4"x1/4" Al along the "seams" and
> drill and tap 6BA (6BA tapping is 2.3mm so probably similar to M2.5) to
> screw the sheet to the square.
> With larger with heavier contents enclosures use larger "square" and
> screws (4BA - M3.5) or 1/2"x1/2"x1/8" Al angle.
> Sometimes, of course, it is neccessary to have individual flat panels but
> the joining method above works just as well for those.

Yes, Al angle is neat. You can rivet it for the connections that "stay".
Please do the world and yourself a favour and use M3 and M4 screws, not
M2.5 and 3.5 ;-)
Self tapping sheetmetal screws work very well here too, maybe even
stronger in the soft aluminum than machine thread.

Somehow, individual panels tend to look very much more "homebrewed" than
bent sides.
Maybe bonding would make that better.
I like to have the front and back panels of a case individual if possible,
because it is easier to make and change cutouts then.


If you need ventilation and have a punch press there are very very neat
punches for vent slots. otherwise you'll have to drill. There'd also be
punches for bending out feet... I really ought to get a press....

ST

On Mon, 12 Sep 2005 20:47:27 +0200, Joe Xerox <joe.xerox@...> wrote:

> Hi,
> I'm interested in this way of building enclosures. Can you post some
> pictures? An how do you bend the AL and make straight and nice looking
> corners?
> Thanks,
> Joe

I use two pieces of angle iron in a vice, and a piece of wood to help
hammer the sheetmetal over.
But then i only made rather small enclosures this way (re-use stuff for
larger ones).
Have bent Al this way up to 40cm long for a heatsink though.
I'd like to have a bending brake, you can make the one on

<http://groups.yahoo.com/group/Homebrew_PCBs/files/Bend_Sheet_Metal/>

or you can get a commercial one, ideally with removeable fingers and a
shear on the same unit ;-)


Oh well, maybe one day... I should start playing the lottery, then i can
dream of buying every tool one day.... ;-)



ST

In article <4325cd49.4a779270.42cf.33c9@...>,
Joe Xerox <joe.xerox@...> wrote:

> Hi,

> I'm interested in this way of building enclosures. Can you post some
> pictures? An how do you bend the AL and make straight and nice looking
> corners?

I don't have a case I'm currently working on ATM, I can take pictures of.

I am very fortunate in that I have access to a metal cutting guillotine
(shear) and bender at work but with retirement looming I have to think of
alternatives. I have already aquired one of those benders that consists of
some pieces of angle iron and a lever, which you clamp in a vice. As far
as cutting goes it might have to be jigsaw or panel saw and a lot of
careful filling, though I'm starting to watch ebay to see if some sort of
guillotine comes up.

Smaller boxes, where the maximum bent length is less than 6" (the width of
my vice) I do bend up in my vice at home. Clamping it up carefully, I then
press against it with a length of 2x1 timber to form (or at least start)
the bend. Thin Al, such as you might use for a small box, bends quite
easily. If neccessary I use a hammer onto the 2x1 but never directly onto
the Al as it marks and bruises it

Ultimately the secret, even with the tools I can use ATM, comes down to
care, patience and practice - like most things.

One tip (and this is difficult to explain) is to make the sides which have
visible edges a little oversize so that when the box is finished you can
trim carefully with a file to get edges that are flush with the sides.

When bending metal you will never achieve a sharp corner, nor should you
try, you will always have a slight radius on the inside so where this fits
over the other piece of metal you will have to file a slight radius on the
corner to match.

When fixing the 1/4" square to the sheet I very carefully position it and
then clamp it. Only when I am satisfied it is in exactly the right
position do I drill straight through both pieces together with the tapping
drill, open up the hole through the sheet with the clearance drill and
then carry out the tapping operation. If using countersunk screws,
countersink the hole before tapping. The screws are then inserted before
releasing the clamp.

With the 1/4" square fixed to one piece, assemble with the other piece and
after careful alignment clamp, drill and tap as above.

Stuart

In article <op.sw0cj5jmmg0lsf@tu-x2pj5qeyp2u4>,
Stefan Trethan <stefan_trethan@...> wrote:

> Yes, Al angle is neat. You can rivet it for the connections that "stay".
> Please do the world and yourself a favour and use M3 and M4 screws, not
> M2.5 and 3.5 ;-)

Actually I don't use /any/ metric screws by choice. I was referencing the
nearest equivant metric sizes to the BA screws I /do/ use for the benefit
of those who may not know what size BA screws are.

Since I don't export anything it matters little to the rest of the world
what size screws I use :-)

Stuart.

--- In Homebrew_PCBs@yahoogroups.com, lists <stuart.winsor.lists@d...>
wrote:

> In article <4325cd49.4a779270.42cf.33c9@m...>,
> Joe Xerox <joe.xerox@g...> wrote:
> > Hi,
>
> > I'm interested in this way of building enclosures. Can you post some
> > pictures? An how do you bend the AL and make straight and nice looking
> > corners?
>
> I don't have a case I'm currently working on ATM, I can take

pictures of.

>
> I am very fortunate in that I have access to a metal cutting guillotine
> (shear) and bender at work but with retirement looming I have to

think of

> alternatives. I have already aquired one of those benders that

consists of

> some pieces of angle iron and a lever, which you clamp in a vice. As far
> as cutting goes it might have to be jigsaw or panel saw and a lot of
> careful filling, though I'm starting to watch ebay to see if some

sort of

> guillotine comes up.

I some times go to local industrial auctions - shears and brakes come
up fairly regularly. The prices can vary wildly based on whose
bidding - I have seen them go from very cheap to above the list price
for new. It doesn't hurt to keep an eye on them. You never know.

I have a Griz 30" combo shear/brake with box fingers and it works
quite nicely for that style of aluminum box. Doubles as a PCB cutter
extrordinaire.

On Tue, 13 Sep 2005 01:53:21 +0200, lists
<stuart.winsor.lists@...> wrote:

>
> Actually I don't use /any/ metric screws by choice. I was referencing the
> nearest equivant metric sizes to the BA screws I /do/ use for the benefit
> of those who may not know what size BA screws are.
> Since I don't export anything it matters little to the rest of the world
> what size screws I use
> Stuart.

yes i know, i was more or like meaning the same, making sure nobody is
really using expensive half sizes.
I reckon for aluminum the US screws would be better anyway, 'cause they
have a coarser thread, and a sharper angle while metric screws have a 90
degree angle i think. Not ideal for soft aluminum (but does work), i guess
they are optimized for same material nut/screw max. pullout strength.

ST