Earlier some one mentioned about building cabinets and metal parts for amps.
Some things do come easier for some than others. That's a given, but to
build an amp and do all the metal work is difficult and time consuming
unless you have the proper tools.
### You fellow's are making a mountain out of a mole hill. Sure,amps are
80% metal work, 20% wiring. I make all my panels from6061-T6 plate...
1/8" thick. Front panel only, is a shinier alloy. All the various plates are
put togethervia 1" x 1" x 1/8" thick ANGLE AL [6061-T6]K7RDX does the
same, or similar. Each individual panel can be removed, andpunched/drilled,
then re-installed. Huge advantage over pre-fab chassis, done ina break press.
Screw something up? Simply replace that one panel. 4 x platesmake the
sidewalls of the chassis, then main surface is added, then the bottom cover
plate.Everything joined via 1" x 1" angle AL. Greenlee now makes a combo
drill AND tap.. [ mouser]that drills and taps a hole, [ and deburs] all in one
swift motion. The kit comes with4-40 6-32 8-32 10-32 10-24 12-24 and
1/4-20/28 . I also use a roper Whitney #5 jr compound hand punch ,comes with
punch's and mating dies from 3/32" up to 9/32" [ in 1
/32" increments,7 x punch's + dies in all] If you can punch AL... punch it,
don't drill it! I also got a BIGGER ROPER Whitney bench punch, with a 25"
armcam action, that will easily punch 3/8" holes in 3/8" thick 6061-T6
platePunched holes are always cleaner than drilled holesMy small drill press
was modified.. and mounted on upside down, 4" channel AL,with a 4" x 4" block
of wood below it. Now the 19" wide sheetscan sit directly to the bench,
clamped down with special vice grips[threaded rod to below bench with quick rls
lock rings. ] All u need is 'A-9' green cutting fluid [for AL] Lets take
the tube mounting and pressurized compartment to start.
There are a lot of holes to put in the surfaces. This takes a punch or
a drill specifically sharpened to drill Aluminum without leaving a burr,
or sharp edge. Edges that need to be "broke" need an even bevel or
radius that doesn't look like it was done with a paring knife.## Nonsense. Any
Zirconium drill bit will easily curt clean holes in AL plate. Ditto with
Greenlee combo drill/taps. Use the 10 ton hydraulic punch to whack the
holes for the socket and blower assy. The holes for the tubes and sockets
must not look like they were done with a hole
saw. This can be done with either a fly cutter, or punch press. Fly
cutters are used on mills which cost more than the amp. They are also
very dangerous. ## fly cutter's are useless things. You can buy a 10 ton
hydraulic punchWITH 5 x large dies and from harbor freight for $89.00 A
fraction of thecost of the eq green lee product. Cuts meter holes, tube
socket holesblower holes in a matter of minutes, real fast. Or borrow one
from urfavorite electrician, they all have one in their trucks. A set of 28 x
TRANSFER punch's is $10.00 from harbor freight tools,perfect to find the
center of holes in vac cap flanges etc. IF you have to cut large diam holes,
like for 120mm fans, etc, I use a Bosch jig saw, with steel cutting blades..
and SLOW the speed WAY down.Cuts like butter. My Bosch looks like a long
sausage, low to the table.I also used the Bosch to cut 3 1/16" diam holes
in 3/8" AL plate,for my Rohn TB-4 bearings, etc. The holes were perfect,
looked they had been donewith a hydraulic punch. U can cut 3/4" thick AL
plate with a bosch. Punch presses take dies as well which are
not cheap
and not normally made at home. Even given the proper press and punch the
hole, or holes needs to be made with out deforming the metal sheet. You
don't just put it all together and punch a good looking hole in a sheet
of Aluminum. It takes a bit of skill. ## wrong. A 12 yr old girl can punch
clean holes within 5 x mins ofbeing shown how to use either a 10 ton hydraulic
punch, OR any of the roper Whitney products. It's that simple. To top it
off, there shouldn't be
ANY scratches in the surface of the metal.## The only place u really don't
want scratch's, is the FRONT panel Of course the dimensions must
be proper and the material sturdy enough to make for a solid
construction.## I get all the al plates sheared in huge press, at the local
metal shop.Pay cash, and don't ask for a receipt. I buy the 6061-T6 plate
there too. They usually have loads of NEW scrap ends etc. Could I use the
equipment to make the chassis and sub
chassis using the drills and fly cutter? Yes I can, BUT I'm not so sure
about the scratchless surface. Any scratches and I'd throw it in the
scrap bin and try again.
## Most AL plate comes with a protective plastic sheet film on one side.Just
leave it on, and drill /punch right through it. Remove, dead last. Zero
scratch's. Could I build a high powered amp cheaper than purchasing one? ##
Moot point imo... since emtron, alpha, etc don't use vac tune and load caps
on their amps. Most won't handle high power on bypass.[I string all my amps
nose to tail, and use a rotary switch to activate separate key lines for each
amp.]The tank circuits in most of them are a joke, esp Ameritron. The 3/16"
tubing in the alpha is clearlyundersized for 20-10m. ## Rolls of 1/4" 3/8"
and 1/2" Cu tubing is dirt cheap at any home depot.I silver plate all mine
with ..'cool-amp' [ cool-amp.com] Ditto with all cu strap. OTOH Cabinets
are fairly easy to make, if you have a good metal brake
and notcher for the inside corners along with some practice. It's those
pesky holes that are the hard part.
## Just rack mount the RF deck into a surplus 19" / 24" rack
cabinet...dittowith B+ supply, etc. The panel is probably the hardest part
as it includes the difficult task
of getting large and small holes in the proper position with clean
edges. Then there is the lettering which can be silk screened,
airbrushed with a template, or grooved and filled. Each takes a
particular skill and no small amount of practice. Maybe the most
difficult of all is just organizing the panel to make it look useful
without being cluttered. This is where most home brew projects really
look like they are home brew.
## what ?? There is minimal stuff on the front panel as is. While you are at
it, buy some digital calipers from home depot, alongwith T square's etc. Those
german stadeler marking pens [.5mm tip]come in loads of colours, and ,mark AL
easily. When all holespunched/drilled, marking lines are removed. There's
a reason they don't have a
row of meters all the way across the panel and only a part of it is to
save money. Rather than designing an amp around a tube or tubes, maybe
it'd be better to keep in mind the size of the tubes while building the
amp based on the front panel design.
## well, I use a row of 4 x new meter's across the front of my amps.plate
V.. plate I ... fil V Grid I I also meter fil current, and also hr
meter on thefil xfmr, and also meter line V, etc. Misc meter's on lower
portion of rack. Hydraulic punch, bam, done. Then add turns counters for the
2 x vac caps+ knobs, etc. Powder coat, or spray paint the front panel, and
it's a thing of beauty.When u fire it up, a smile comes across your face,
knowing you just beat Henry radio,Alpha, Harris, and Emtron, etc.. hands down.
At least with HB amps... you can properlysize the components. Jim VE7RF
73
Roger (K8RI)
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