rOn Fri, 03 Feb 2012 21:18:50 -0500, you wrote:
>Thanks for the advice guys. I've seen the bits with the 1/8in shanks and
>my first thought was to not use them because they cost 2 or 3 times more
>than the constant-diameter bits. And I'm thinking these bits break
>easily and so replacement cost is something to keep in mind. Hence my
>inquiry re collet or perhaps a chuck for bits under 1mm in diameter.
I have a proxxon tool, the 120 volt model. It has less runout than a
dremel (and I've tried at least two of them). The main thing that
bothers these smaller bits is that they cannot bend, so any runout or
wobble in the press makes the drill break.
You want at least 20,000 RPM for the smaller ones, say #55 and
smaller, and adjustable speed for the larger ones, like a 0.125 used
for mounting holes.
The steel bits will not last, they will be sanded away into a needle
shape by the fiberglass in the PC board. The carbide drills last a
lot longer.
Harbor Freight, for about 7.00 per package, sells 20 assorted (think
it's 20), carbide drill bits. Not all the sizes will be useful, but
they are at least, cheap. It's possible that the online store has
larger assortments than the retail stores.
Again, a drill press, high RPM, and no wobbling will be your friend
here.
Harvey
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>
>Steve K8JQ
>
>On 2/3/2012 7:36 PM, John Anhalt wrote:
>> All of my small carbide bits for PCB work have 1/8" shanks.
>>
>> John
>> ----- Original Message -----
>> From: Branko Badrljica
>> To: Homebrew_PCBs@yahoogroups.com
>> Sent: Friday, February 03, 2012 9:10 PM
>> Subject: Re: [Homebrew_PCBs] Proxxon 38128 drill press -- collets for small bits?
>>
>>
>>
>> Dne 03. 02. 2012 23:02, pis(e Steve:
>> >
>> > Hi all,
>> >
>> > A couple of weeks ago I inquired about small drill presses for PCB work.
>> > I'm kinda leaning toward the Proxxon 38128. Looks like the drill press
>> > comes with six collets, the smallest of which accommodates 1/32in (about
>> > 1mm) shank size.
>> >
>> > I'd like to be able to use a #76 bit and perhaps a #78 bit with this
>> > drill press. Anyone know if collets are available for the 38128 for
>> > those smaller size bits? If so, what is the source?
>> >
>>
>> This is not AFAIK meant for PCB work. It's for general-purpose work.
>>
>> I use drill stand MB 140/S (NO 28606) + IB/E drill/grinder ( NO 28481).
>>
>> Drill stand has extra bolt for elimination of air gap and it's very precise.
>> IB/E drill unit has high yuality bearings and can achieve high rpms,
>> needed for PCB drilling with hard drill bits.
>>
>> Regards,
>>
>> Branko
>>
>> >
>> > Thanks.
>> >
>> > Steve K8JQ
>> >
>> > --
>> > Read The Patriot Post Vertitas vos Liberabit
>> > http://patriotpost.us/subscription/
>> >
>> >
>>
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