On 5/4/2013 7:02 AM, Colin Lamb wrote:
It is not too difficult to build your own chassis. Laying out the metal (with
all the required ears) is the most demanding part. A shear is not necessary.
Cutting exactly is the most difficult part, but metal fab shops can cut it to
shape. Although I have a large metal brake, the $50 work quite well. For
boxes, I just saw up some surplus angle iron that is the proper length. To
finish the boxes, pop rivets can be used, although real rivets look much
better. A hand riveter will do most of the riveting required for a box.
Find a new friend who is building a metal airplane. Chances are they have all
the tools and will help you learn how to do it. Or, build an airplane to give
you the skill to build a box.
These are good suggestions for the home brewer but we are looking for a
small job shop that can do projects at reasonable prices.
First, no one has defined thick or heavy. Are we talking 1/8", or 1/4"
or what? Home brewers are likely thinking of thicker and softer alloys
than the shops.
I have chassis that are both. For the latter you need a metal band saw
or one massive shear and a TIG welder, or build it erector set style.
Usually the Erector Set style is neater. A milling machine with a saw
is great for cutting 1/4" and leaving a nice finished edge.
I consider a shear essential unless you are not considering looks. Only
a few have the skill to saw and file with a professional look. I'm not
one of them and I've received compliments on DIY projects. Doing it
professionally is a whole different ballgame.
We are talking about doing this for others, not "good enough" for a
home "Do it Yourself" project
Aircraft fabrication seldom involves metal sheeting heavy enough to even
construct a small chassis considered light duty. They get their strength
from shapes and use thin metal for weight savings. Most airplanes are
built like beer cans, including the monsters we pay to ride in. It'd
never stand up under a 40# transformer, let alone an 80 or 90 pounder.
So it's doubtful you'll find what you want going that way. But! It's
worth a shot.
Incidentally, the small sub chassis that holds the two 3CX400A7s in my
old Alpha is about twice the thickness of aircraft skin.
Often in larger chassis you will find angle runners to add strength and
sometimes doublers Like tube sockets mounted on a square or rectangle
that fastens to the chassis. This is primarily money saving rather than
weight savings.
73,
Roger (K8RI)
73, Colin K7FM
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