I have no mill (until now)
but on a german page i read he couldn't manage to get a board milled
without "depth foot".
he wrote the board material was not flat enough and the triangular shape of
the bit
caused the resulting milled grooves to be wider/narrower depending on
height of pcb.
he also wrote this effect is very dependent of the mill bit tip angle.
and i assume it is also very dependent of the board quality.
i don't remember the url but if you can read german i may search it.
but i have seen several pages where a sensing head is described.
the device the guy uses is made on a lathe (i think of aluminium.).
it is VERY important to use a vacuum then for dust because otherwise it
will lift up the sensing foot.
also i may suggest you think about this dremel tool again.
i have seen a handful of webpages where the guys ended up building their
own spindle
with loaded bearings because the dremel was too bad.
maybe you can use a proxxon IB/E or another better motor....
if you design a motor mount for your new spindle maybe you want to add
sliding
capability if you ever need the sensing depth foot....
st
On Mon, 18 Aug 2003 23:27:43 -0000, crankorgan <john@...> wrote:
> Arnie,
> I buy 4" X 6" single sided boards. I mount the board on a piece of 1/4"
> pvc plastic which is mounted to the bed of my machine. The blank board is
> held by the edges to the PVC using the heads of 4-40 bolts. The board is
> held on three sides with two bolts per side. one bolt is added to the
> forth side after the blank is slid in and the bolts tightened. Because
> the tip of the bit is triangular, variations in board thickness and
> flatness do not show up if you stick with boards 4" X 6" or under. The
> real machine has an adjustable foot and a vacuum system to remove the
> dust so it does not affect the foot.
>
>
> John
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "acfrankenberger"
> <acfrankenberger@y...> wrote:
>> I wasn't planning on using a depth guide. If I keep the boards flat will
>> I be ok, or am I kidding myself?
>>
>> Thanks,
>> Arnie
>>
>> --- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan
>> <stefan_trethan@g...> wrote:
>> > why don't you use a household hoover with a flexible
>> > hose (for electrical installations there are thinner ones) to get rid
>> of > the dust?
>> > > the glass is bad for the bits...
>> > > > here nearly anyone offering fr4 has phenolic too...
>> > > any supplier should have it..
>> > > i can't tell you names because i am too far away...
>> > > > you should have a sliding milling depth guide for isolation
>> milling. have > you?
>> > > st
>> > > On Mon, 18 Aug 2003 20:08:05 -0000, acfrankenberger >
>> <acfrankenberger@y...> wrote:
>> > > > I have a Taig mill I was hoping to use to mill out (trace
>> isolation) and > > drill some circuit boards. Would phenolic based
>> boards make the milling > > process less demanding on the tool bits?
>> Could I avoid dust collection?
>> > >
>> > > Does anyone have a source for phenolic copper clad boards?
>> > >
>> > > Thank you,
>> > > Arnie