On Sat, 23 Feb 2019 22:11:11 -0500, you wrote:
THANK YOU HARVEY!!!.......ALL VERY IMPORTANT AND NOTE WORTHY
but
we are talking here on HOME BREW PCBs forum and sometimes we really are
home brewing PCBs and
Hmmm
The only expensive thing is/was the license for EAGLE as a
hobby/student.
Lazarus pascal is free.
Open SCAD is free.
The editor I use for it is free.
The programming I wrote, other than the time I put into it, is free.
If you want, you can add the cost of the digital calipers, but I use
them in the machine shop, too.
not investing in expensive professional tooling.
It isn't expensive, but the question is whether or not (and how many)
carbide drill bits you break.
I've broken a few. (and yes, got them from Harbor Freight, but I use
them a bit differently).
My projects are probably a little more complex than average, so I have
a lot of holes to drill. In doing double sided boards, I *have* to
get the holes to line up. Accuracy in drilling the guide holes is
critical. How to align the boards is also critical. The vias in what
I do are small enough that I can misalign a board top to bottom by a
little bit, and the holes and pads don't line up at all. That board
is ruined
Steel bits last only so long, but that depends on the material of the
board. Paper phenolic is epoxy and paper, and isn't very abrasive.
FR3 or FR4 is glass embedded in epoxy resin, and cutting through glass
is nasty for plain steel bits.
IMHO, Proxxon makes better quality tools than dremel. Less runout on
the bearings and four jaw steel collets rather than three.
This is not about "my" way being better than yours.
I make boards with a certain tolerance, certain chip styles, and a
certain amount of parts/square inch. Most of them are now surface
mount, which is a whole 'nother argument.
What I do for the boards I make tends to indicate that I make them in
a certain way, with certain tools.
The most expensive tool I got was likely the proxxon. The upside down
drill press was an interesting project, but not everybody wants one or
would need it. It answered a partucular need, and yes, I built it and
it had some expensive (to me) parts.
The laminator was a standard one, so going for toner transfer PCBs was
relatively easy.
So this wasn't (to me) expensive, and if what you do satisfies you
(and it certainly seems to), then go for it.
I have different requirements, different projects, and to get those to
work, I need to do things differently.
This isn't about better, or right, or wrong, it's about different ways
of doing things.
Harvey
I have been hand drilling at low speeds...dead batteries.... using
DREMEL pumpkin cutters:
for 4 years.
ANYone can do this for home brewing PCBs in their kitchen.
and easily plunge accurate holes that will hold 28 pin DIP chips.
I do not use 5 different drill bits.... like? for tiny 1/8th watt resistors
and bigger transistors.
I drill just one size hole and when I need a bigger hole I go back and
give a angled twist and grind a bigger hole.
I have broken some drill bits and have learned that if I design my PCB
to have a PLUS sign or round hole then
the drill bit finds center and doesn't argue much and doesn't break.
This particular HARBOR FREIGHT rotary tool? was note worthy to share
because it is definitely half the price
of the dremel pumpkin cutter and plugs into the wall.
Which means top speed will be attained every time....
compared to dead batteries in my dremel tools.
Now about wobble .........
I have drilled at least 1,000 holes in 4 years with my dremel pumpkin
cutter and only recently
have noticed wear and tear and wobble.
That is one reason I bought another toy from harbor freight.
If this toy lasts a year before wobbling I got my $9 out of it.
And YES black carbide drill bits are fragile and do shatter.
ALWAYS wear eye protection when spinning any cutting tool.
Sometimes I wear a ski mask that has a built in condensation clearing
fan when I
grind and cut 1/2 inch steel? threaded rods with dremel cutoff wheels.
I buy my drill bits in packs of 100 or more and right now I have enough
to last until
I die so I don't care if I break THE ONE BIT I will use that came with
the rotary tool.
Have fun.
I am.
Rob
On 02/23/2019 09:41 PM, Harvey White wrote:
On Sat, 23 Feb 2019 21:06:37 -0500, you wrote:
Carbide drills are extremely sharp.
They are also extremely fragile.
They cannot tolerate any kind of force that would make them bend.
They have a limited tolerance to torsion (twist) so if they get
caught in something, they're likely to break off, often at the top of
the drill part.
Having said that, if you put them in a drill press, the faster the
better (seriously, you want anything between 20000 RPM and 60000 RPM,
depends on the drill size), they'll last a long time.
Main problem with the harbor freight sets is that you can't control
what sizes you really need, and you normally need to clear 0.025
posts, IC socket tabs, 1/4 watt resistors, and then any wire you use
to bridge the top and bottom planes. If you don't do that, they they
need to clear the wires needed for jumpers, if you use any.
*please* put them in a drill press.
And runout (wobble in the chuck) is absolutely critical, the less, the
better. At 50,000 RPM (or even 20,000), a wobbling drill bit cuts
something that's not necessarily round, and certainly NOT the intended
diameter.
Proxxon seems to be best for the tool, less runout than dremel (got
both). the 12 volt version seems to have enough torque to drill, but
for the drill press itself, it can't wobble. Just like taps,
perpendicular is the gold spot, you don't want an angled drill.
If you ever go to double sided boards, you need to build something to
drill holls *very* accurately. Check if there are any posts that I've
written on "upside down drill presses".
And past a certain point, if you don't need one, you may feel as if
you *should* have one.
I could repeat the posts, but that's only if someone is interested.
Harvey
PCB holes drill? from HARBOR FREIGHT??? $9
the tool:
DRILMASTER????? #63235????? ROTARY TOOL KIT
comes with all sorts of grinder and polishing tips and the ONE drill bit
I use to drill PCB component holes.
The ONLY reason I bought it was to drill PCB holes.
and
I was LEARY.
Because I have another one that looks just like it but the voltage is
9volts on mine
and will not drill clear through a PCB.
THIS ONE IS 12 VOLTS
so
the acid test was to punch some holes in PCB
AND IT WORKED GREAT!!!!!!
So..... no more battery operated DREMEL pumpkin cutters for me.
