Building Chassis

[Detroit47]

Try this place out. I know it's geard to CB but nice cabinets cheap.
http://icamanufacturing.homestead.com/

John N8QPC

[N6YW]

Chassis can be made inexpensively. If you do the proper layout and allow for the radius's and corner bend holes, a local sheet metal shop will usually charge you a nominal fee for bending. Make sure the type of material you use can be bent without splitting. If you do not plan on bending a chassis, then fabricate it using 90 degree corner stock and screws or rivets etc... just like they did in the ARRL handbooks.
We all have ideas on this subject and let me state something obvious, you DON'T have to spend a bunch of money, just spend wisely where needed. Attention to details is key and if you have doubts about doing certain operations then consult with someone who can. Common sense and sharp tools.
A Uni-Bit costs around 20 bucks for the standard 1/8" to 1/2" model. These will stay sharp a long time if you use cutting fluid and go slowly.
I forgot to mention the most important aspect of all...
HAVE FUN!

[N6YW]

Now where can I get a chassis from that doesn't cost a fortune?

Old HP test equipment from the 50's, the really big stuff can be had for pennies and stripped down to the chassis. Cut out the entire chassis face with the exception of a 1/2" to 3/4" lip all the way around. You then attach a new chassis face complete with your holes in place.
Done.
You also have the benefit of the cabinet and associated hardware, that includes all of those 4-40 and 6-32 screws in abundance. Your fastener cost is already paid for.
I built a linear amplifier out the same model unit shown in the picture here. Great hardware too. I made a different faceplate to accommodate my layout. Fun.

[WQ9E]

NEVER use a hole saw on a drill press!!! This is fool hardy and dangerous as hell. Use the slowest drill speed you can to make your drilling operations not only clean but safe and it helps to maintain the structural integrity of your drill by not overheating them.

I am curious as to your reasons for "NEVER use a hole saw on a drill press" 

Also,  someone new to machining might misinterpret your slowest speed comment since too slow a speed for the cutting bit also is bad for the cutting tool and leads to a poor cut.  Manufacturers (both cutting bits and the machine tools that use them) generally provide recommended cutting speeds which should be followed.

[AB3FL]

Has anyone used the chassis cases from tubesandmore.com?  They have some nice Hammond cases for reasonable prices.


Tom

[KL7OF]

I'm a newbie, and the "keep it simple" advice given above has been good to me.

I've been doing a fair bit of metal work with two hole saws, two step-drills, a nibbler, a reamer, a collection of files, a collection of drill bits, a black&decker, a dremmel, a pair of lab goggles, a hand saw, and my own two hands. I also use my thighs and feet to hold stuff in various orientations during drilling. Finally, a bunch of wood pieces and clamps are sometimes used.

Here's something I've been putting together recently (I've cannibalized the aluminum enclosure and other parts of a BC-375 tuning unit in which I put a chassis cover with angle stock):

http://imageshack.us/f/215/img1655gf.jpg/

http://imageshack.us/f/853/img1671m.jpg/

LOOKIN' GOOD!!!

[K3YA]

Now where can I get a chassis from that doesn't cost a fortune?

Buy an old used chassis at a hamfest that's full of holes for cheap.  Cut off the top leaving 1/2 around the edge.  Pop-rivet a new top of fresh aluminum on it.

This was built with a hand held electric drill, a saber saw, and a couple files.  I was much younger when I did it. If you have time you can get by with some simple tools.

[KL7OF]

Step bits can be sharpened.......Look at the edge that cuts...If you dress a grinding wheel to a square (90 deg face to edge) and the radius of your grinding wheel is close to the one the factory used, it is simply a matter of holding the bit on the face and side of the wheel...The side of your grinding wheel is what will sharpen your unibit...take a close look at the bit and you will see how the factory did it.....

[N6YW]

NEVER use a hole saw on a drill press!!! This is fool hardy and dangerous as hell. Use the slowest drill speed you can to make your drilling operations not only clean but safe and it helps to maintain the structural integrity of your drill by not overheating them.

I am curious as to your reasons for "NEVER use a hole saw on a drill press" 

Also,  someone new to machining might misinterpret your slowest speed comment since too slow a speed for the cutting bit also is bad for the cutting tool and leads to a poor cut.  Manufacturers (both cutting bits and the machine tools that use them) generally provide recommended cutting speeds which should be followed.

By my experience.
Most drill presses don't have a slow enough gear ratio to allow for a hole saw. Just sayin.
For the inexperienced it is a safe bet not to. I agree to your comment about too slow to an extent.
Mostly, if you follow the tables set forth by machining practices and procedures.
Anyway, we are both saying the same thing.
A rule of thumb is this: A too fast cutting or drilling speed can screw something up much worse than using too slow a speed. Your reaction time is better with a slower speed too. There is a balance here for sure.

[Opcom]

Greenlee punches

second that. Nice holes for Octals! Irvin "Frank" Miller W5PBN (SK) gave me an old set long ago and I've always loved them.

For chassis building method, a transmitter here used exclusively 90 degree, 1/8" stock and aluminum 1/16"panels except for the front. To the best of my observation, the stock and the aluminum panels were cut to size and these chassis parts were laid next to each other, clamped, and a hole drilled every inch or so through the panel and angle as a unit. The holes in the steel angles were then tapped, and the holes in the panel were slightly enlarged to accommodate any errors in the hand assembly process, and machine screws were used to assemble the RF deck, piece by piece. Just saying, it is extremely rigid despite its size and can be tilted up on a corner without deformation despite the thin materials and 100 LB weight.

[WQ9E]

N6YW,

Thanks for the explanation.  Both of my drill presses have a slowest speed of around 200 RPM and the charts specify hole saw operation at the low end.  I agree that these hole saws should never be used at high RPM and they certainly aren't balanced for smooth operation at high speed.

I have purchased some hand tools from Harbor Freight but one thing I do not trust from them are high speed cutters like router bits.  Although they are probably OK when I have something spinning at >20K RPM I don't want to chance poorly brazed carbon cutting tips.  

[WU2D]

I like the simple list above and I do use step drills in my cordless hand drill.  A 1 Inch Greenlee punch is a natural and chainsaw files and the like are great!

[Ed/KB1HYS]

Now where can I get a chassis from that doesn't cost a fortune?

Well, a good place to start (if your cheap like me) is the local landfills reclaim/recycle area.  A lot of folks dump old Microwave ovens and such. Take one or two home, pull the guts salvage every usable part (and there can be a lot, microswitches, relays, the transformer, diode & HV oil cap, etc), the cases make nice enclosures for just about anything from a home brew 100watter up to a pair of 4-400 in a linear.  Sometimes sheet aluminum can be had at the scrap yard in odd sizes. Cut to squares, use thin aluminum angle stock and rivets and you can make a very nice chassis and enclosure.   Store-bought stuff is very nice and purty , but you pay for it. With a bit of sweat equity you can make something more durable, and just as good looking.

And you can say, "I carved this rig out of solid steel with my bare hands." or something similar and REALLY impress the visitors to the shack.

[Opcom]

Now where can I get a chassis from that doesn't cost a fortune?

Buy an old used chassis at a hamfest that's full of holes for cheap.  Cut off the top leaving 1/2 around the edge.  Pop-rivet a new top of fresh aluminum on it.

This was built with a hand held electric drill, a saber saw, and a couple files.  I was much younger when I did it. If you have time you can get by with some simple tools.

That's really a nice looking job for the tools used. It's more the workman than the tools.

[N6YW]

When building a power supply chassis or combining the supply with the deck components, it is best to use thick enough material to handle the weight. Transformers and big chokes can cause the chassis to dish or distort.
To remedy this, I use a stiffener plate that bolts through the chassis deck. It adds more integrity and if done real neat can add a very cool industrial finish that speaks old school. A less elegant approach but very suitable is to use a stiffener made from 90 degree angle stock running lengthwise along the longest width of the chassis.
Use what ya got, and what Ed said is the best. Making use of already discarded materials rocks.

Here is an example of when I cut out the chassis deck of an old video clamper that was riddled with holes. It was the perfect donor for this LA2A compressor project at my old recording studio. I ended up riveting the new plate in place. I left the old logo too, that jet motif looks really cool.
This chassis was being thrown away as useless junk. I scavenged it right away! The comments from clients was rewarding in that not many recording studio's have in house built equipment. They took a different view towards you upon that little discovery. Anyway, you get the idea.

[K9PNP]

The best way I have found to build a chassis is with street sign aluminum and C-channel.  The aluminum in the signs is hearty stuff;  consider the forces on it on a post with 2 bolt fasteners.  Used with the C-channel, you don't need bend the aluminum sheet.  I get mine from the local street dept when they take signs out of service.  May take some straightening at times, but for what you get it's worth it.  Made this way, you can put a KW power supply on a chassis without having to worry about structural integrity.  And for VFOs and receivers, less flex means better stability.

I will echo the need for a drill press if you do much homebrewing.  For me, it makes things easier.  For layout I have used wide masking tape on the chassis.  Also keeps scratches, etc, down.  One note on chassis punches:  If you use the heavy aluminum like I do even some of the Greenlee punches are not up to it.

[W7TFO]

 One note on chassis punches:  If you use the heavy aluminum like I do even some of the Greenlee punches are not up to it.

You may find using the optional ball-bearing pull studs make for easy work up to 3/16" T-3 plate.

Keep the parts freely lubricated whilst working them.   I use synthetic motor oil, it really makes things slippery and you use a LOT less energy.

If your punch really distorts the metal, it is most likely dull and needs to be hit by a good stone to get that edge back to cutting cleanly.

If you have access to a hydraulic press like those in auto shops, you can punch anything up to 1/4" alum. & 3/16" steel with a Greenlee.  Set up the punch as usual, and let the ram do the work rather than the screw action.

73DG

[N6YW]

Quote: "One note on chassis punches:  If you use the heavy aluminum like I do even some of the Greenlee punches are not up to it."

Ditto. There is a limit to those punches. 1/8" is the max I have ever tried and it distorts the plane or flatness of the surrounding area. At that point you need a hydraulic press with the proper bed or caul to maintain flatness.
A hole becomes a good friend at that point.
 *** sorry I posted at the same time ***

[N4LTA]

The Hammond chassis are good quality and available in aluminum and painted steel. They have a good selection of sizes. I use them all the time. I especially like the black poweder coated ones. The steel is mild and drills and punches easily.

Pat
N4LTA