Homebrew PCBs

On Sun, 31 Jan 2010 16:10:32 -0800, you wrote:

>Hi,
>
> 
>
>This discussion is immediately interesting. I'm at the stage where I
>need a drill press for PCBs. Because I'm already heavily invested in the
>Dremel system, I was about to buy the Dremel drill press to use with my
>XPR tool. I looked at the Proxxon system. It's nice and may be better,
>but I do NOT need (and can't afford) yet another tool system!
>
I can understand that one.

> 
>
>Can someone tell me more details of the problems alluded to with the
>Dremel? Can they be fixed with a little machining to tighten tolerances?
>(I did that with their routing table.) Would just taking extra care be a
>workaround? Or, is Dremel a totally lost cause for PCBs?
>

The drill stand wobbles from side to side, which could be fixed.  I
never bothered because it did work.  Takes a bit of practice, but it's
ok.  The collet is pretty miserable, being made of aluminum and 4
flutes allows it to be off center.  This introduces an unpredictable
wobble (runout) in the drill.  At 20K RPM, you risk killing a carbide
drill (say in the finer than #70 range, perhaps), but the holes are
oversize.

The Proxxon uses steel collets that are 3 jaw construction, and seems
to be a lot nicer.  Whether or not the Proxxon collets fit the Dremel,
and whether or not that would fix the runout problem on the Dremel, I
don't know.

Extra care is fine, but it depends on what you're doing.

I use about a 0.030 drill for the ICs (0.025 square post, etc), and a
#70 or #71 for through hole parts leads at the finest.   When making
vias for some boards, I use about a #78 drill, or perhaps a bit finer
(#80).  There is where the runout can be a problem.

If you have the Dremel already, and use carbide bits, you will get
satisfactory operation with the Dremel.  The Proxxon is a step above,
but it's up to you to decide if you need the extra expense.  The
Dremel drill stand is certainly useful, and I don't regret buying it.

I just wanted better after a while.


Harvey


> 
>
>Jim
>
> 
>
>From: Homebrew_PCBs@yahoogroups.com
>[mailto:Homebrew_PCBs@yahoogroups.com] On Behalf Of James
>Sent: Sunday, January 31, 2010 11:45 AM
>To: Homebrew_PCBs@yahoogroups.com
>Subject: [Homebrew_PCBs] Drilling
>
> 
>
>  
>
>So what do you guys use for drilling boards? I have a cheap drill press
>which is barely adequate for occasional drilling, but there's enough
>slop in the quill that it's extremely difficult not to snap off <1mm
>bits. I've had the best results using the manual mill at a friend's
>machine shop but it seems silly to use a 3HP spindle to turn a .85mm
>bit. I almost bought one of those little Dremel stands since I have a
>couple of the rotary tools but I've heard they are flimsy and don't work
>well. Is there a good low cost option or am I best off just building
>something myself?
>
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