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<p><font size="+2"><font face="Times New Roman"> Left hand
twist drills might be an op<font face="Times New Roman">t</font>ion
to consider. You<i> MIGHT </i>snag the offending piece of
twist drill and back it out. :)</font></font></p>
<p><font size="+2"><font face="Times New Roman"><br>
</font></font></p>
<p><font size="+2"><font face="Times New Roman"><font face="Times
New Roman">RJ</font></font></font><br>
</p>
<br>
<div class="moz-cite-prefix">On 3/5/2017 7:55 AM, Chris Tromley
wrote:<br>
</div>
<blockquote
cite="mid:CAC36KhH4mnXmogCgV+YpWUJfdHzv74YJ0Rn5k6BWaz2iF3et2w@mail.gmail.com"
type="cite">
<div dir="ltr">
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif"><span
style="font-family:arial,sans-serif">On Sat, Mar 4, 2017 at
4:31 PM, Christopher Zach </span><span dir="ltr"
style="font-family:arial,sans-serif"><<a
moz-do-not-send="true"
href="mailto:cz@alembic.crystel.com" target="_blank">cz@alembic.crystel.com</a>></span><span
style="font-family:arial,sans-serif"> wrote:</span><br>
</div>
<div class="gmail_extra">
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">By
grinding the bolt flush with the post and using a 10/32
tap and drill set I was able to get four of the cells
drilled, the old bolt drilled out, and new threads tapped.
Of the other three one had a drill bit in it already, and
I broke two bits trying to drill out the remaining two. So
now I need to drill through drill bits. Not fun.</blockquote>
<div><br>
</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif">Not
familiar with BB600s, but drilling out drill bits will be
tricky business. I've never had to do it myself. If
presented with that problem, I'd hope that the drill I
broke off was made from high-speed steel (the most common
type). Then I'd go to McMaster-Carr or some other
industrial supply house and get some carbide drills. Not
sure if carbide is hard enough to make that work. Maybe
search on what you're trying to do first, and you'll
likely get some hits on machining discussion forums.</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif"><br>
</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif">Typically
you remove a broken drill bit by EDM. But that requires
immersing the BB600 in a dielectric liquid, which would
likely be hard to keep out of the plates. Or not?</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif"><br>
</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif">Good luck,</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif">Chris</div>
</div>
</div>
</div>
<br>
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</blockquote>
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