Homebrew PCBs

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