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Subject: Re: [Homebrew_PCBs] Accurate drilling

From: Harvey White <madyn@...>
Date: 2016-06-22

On Tue, 21 Jun 2016 17:20:09 -0700, you wrote:

>I’m having good results with my dremel – it’s just very hard to see where the bit is in relation to the pad when it’s on. If it were a convenient push button operation I could position the bit, then just lift a little, hit button, and go. I’ve not had any drifting issues at 30k RPM with a quick up and down motion.

A very bright light shining through the board will help. You might
also want to try a bright light on the top as well. You may try
putting a mirror off to the side at a 45 degree angle so you can see
the drill bit coming down from directly forward, and at the same time,
from the side. You put the drill bit down with the dremel off, just
barely touching the board (otherwise you worry about breaking), and
then press the footswitch and drill.

Harvey

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>I thought maybe putting a small laser or LED under the center of the base to illuminate center above might help a bit… need to find one among my stuff here.
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>From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
>Sent: Monday, June 20, 2016 4:19 PM
>To: Homebrew_PCBs@yahoogroups.com
>Subject: Re: [Homebrew_PCBs] Accurate drilling, cutting?
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>If you have occasion to find a used Cameron micro drill press, don’t hesitate to buy it. They are extremely precise and can run up to 30,000 RPM. I bought a model 164 with the standard 1/8” Yukiwa drill chuck, and had a very difficult time measuring any runout with a Starrett Last Word DTI run against the shank of a carbide drill bit. Specified spindle runout is only 0.0002”, or 0.05 mm.
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>The only drawback, if there is one, is that the maximum depth of work is a bit limited, but much less so than with the Dremel. I’ve only broken bits by bumping the work piece against the side of the drill.
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>All the best!
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>Bob
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