Hi Alan,
I just bought a new Dremel multipro a few weeks back. It
does 30,000 without breaking a sweat. My first Multipro developed
some runout that comes and goes. After that experence I have learned
to keep the Dremel at Number 3 for best results. I got my numbers
from the guy at Think & Tinker. A real shocker to find out the Taig
and Sherline spindles are too slow. So many people were claiming they
were making circuit boards with them. It's Dremel or nothing. I made
a homemade spindle using race car motor. Thought it was quit until I
bolted it to the machine. I just wish there were cheaper bits. Dental
bits don't come with 60 degree tips.
On the internet you always see test boards with a few traces.
The problems show up after 20 minutes of cutting. This is when you
are on the other side of the board. The bit is getting dull and the
board is getting thicker. Everything in life is easy until you do
it for real.
John
--- In Homebrew_PCBs@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:
> Hi John,
>
> I have a Dremel tool adapter for my Sherline mill, which is CNC.
The
> Sherline is for CNC, not PCB's, as they would have to be less then
3"
> wide on my old Sherline.
>
> My wife bought me a new Dremel tool, since I hadn't seen my old one
> since we moved. You guessed it, I found my old one (20+years) soon
> after. The new one does 30000 RPM as I recall, although I'd rather
> experiment with the old one first.
>
> My real PCB router project is still in planning, I have an
assortment of
> surplus parts which should give me a 12" x 12" table. All I need is
> time to get stuff put together. Making the bridge frame (1/4"
aluminum
> plate) and the base will take a while. And it seems I always have
other
> projects that need attention! One is the controller program to run
it!
>
> Which Dremel are you using, the one with a 30000 top end? Yes, I
know
> of think and tinker, and also Tinkers-emporium, where I bought a few
> boxes of assorted carbide drill bits. I think my engraver bit came
from
> MSC, a tool supplier.
>
> Your feed numbers are interesting. I've never sat down and worked
them
> out before. Where did you get your numbers?
>
> crankorgan wrote:
> >
> > Hi Alan,
> > I don't mind the short life of the tool, its the
> > cost. The bits are $7 each when you buy ten and you have
> > to buy ten!
> > I am milling at 6" per minute with a Dremel. That's
> > 15,000 RPMs. The bits can move .0004" to .0006" of feed for
> > every RPM. That's the speed limit. So if you own a Taig or
Sherline
> > you are out of luck unless you bought the 10,000 RPM spindle. That
> > gives you 5" per minute for $1000 worth of machine. Alot of the
> > EXPERTS out there never mention this. This is how I know they have
> > their boots on and their shovels in hand. There are no bits out
there
> > that can mill boards with slower spindle speeds unless you
> > slow the feedrate down to a snails pace. Have you ever droped by
> > Think and Tinker? That where I get my bits and info.
> > A real circuit board machine has a 20,000 to 50,000 RPM
> > spindle. I ran my Dremel at 20,000 for awhile. 15,000 RPMs gives
> > me good Dremel and bit life. I have made over 200 4" X 6" boards
> > to date. I save the old bits. There are people out there that
> > do re-sharpening. I might even give it a try myself.
> >
> >
> > John