Chassis Design

[defaced]

No expensive Tig/Mig welding, although the choice aluminum solution is riveting (just watch the zillion airplanes flowing all over the world .... which AFAIK do not "melt" in the air either).

So NASA should have riveted those aluminum fuel tanks together?

[soundguruman]

So NASA should have riveted those aluminum fuel tanks together?

One of the materials used by NASA to assemble the space shuttle boosters was duct tape.
No, I am not making this up, absolutely true.

[J M Fahey]

I think those tanks were made out of very thin stainless steel, so thin that they keep their shape only because of internal pressure.
I don't feel comfortable that close to the edge of the precipice.

[defaced]

Nope. They are aluminum-lithium alloys friction stir welded together: http://www.nasa.gov/centers/marshall...n_friction.pdf. For a more applicable example, look at Hammond's 1444 series amp chassis: spot welded. Ever looked at an aluminum trailer, MIG welded. And lastly, look at an aluminum bike frame, TIG welded. Aluminum is quite weldable, and is done for reasons revolving around the design and application of the end product, same with rivets. Saying one is better than the other is like saying steel is better than aluminum or vice-versa (especially in broad categories like "steel" or "aluminum", neither of which are specific enough to have a real engineering design conversation around).

[J M Fahey]

Cool !!
Your data is fresher than mine
Loved the Hammond chassis too.

[lowell]

This thread is great! JM you have impressive skills, and determination.

[lowell]

JM how do you go about cutting a hole for an IEC receptacle?

https://vetco.net/spree/products/619...02.?1464810608

[J M Fahey]

Your link looks like a virus, at least it´s a hidden executable, so I left it there.

In any case; I *would* have ordered the proper die set (for a mechanical press, not a Greenlee type one) but it´s too large to fit in my small punchers, so I cheat by punching my trusty rocker switch holes 3 times, one at each end, and the third cutting the narrow leftover column in the middle,I end up with a proper sized rectangular hole .
Does not look perfect, buy typical IEC all around rim covers it so no big deal.
Sadly, such punching must usually be made on flat sheet before final bending and assembly, not possible on a finished chassis ... unless you can pull a few screws and remove just the flat front or back panel.

[lowell]

It was a link to an image. All good though.

Its an IEC receptacle for those AC mains plugs. Like most desktop computers have. I've been drilling a circular hole and then using nibblers to do the rest. Works, but is more time consuming with a not so elegant result. But I guess these things really boil down to practice.

[SoulFetish]

It was a link to an image. All good though.

Its an IEC receptacle for those AC mains plugs. Like most desktop computers have. I've been drilling a circular hole and then using nibblers to do the rest. Works, but is more time consuming with a not so elegant result. But I guess these things really boil down to practice.

Here is how I make quick and easy work of creating an IEC hole using a drill and file:

• I mark and make drill 3 pilot holes to line up the center of mounting hole with the two mounting screws. Then, I drill 3 more pilot holes on each corner so I can remove as much material with the drill as possible around the edge of the hole.


• Then I just use a drill bit sized to give me a comfortable radius for the corners and drill out each pilot hole. To remove the bulk of the area left towards the center, I use a step drill with a diameter large enough to get me reasonably close to the width of the mounting hole.


• With the bulk of the material removed, I quickly file the rest of the material away to shape the desired dimensions (this part maybe took a little more than a minute or so).


I was really happy with the quality of the results and a huge plus was how quick and easiy it was to do. It took me longer to type out this post than it did to fabricate the IEC mounting hole on my chassis. Here is the result–




of course, even quicker and easier would be to use an appropriately sized rectangular punch. Often these are quite expensive, but
dchang0 came through huge and found this punch for us!
| 31.4 x 28.3mm Hand Rectangular Punch and Die Tool |