Bowers Boremike zero setting

[oldjag]

I have several Bowers Boremikes, on one of them the zero is off by
0.0003". I bought these used and have no manuals. They are the
mechanical type with the plastic window over the micrometer barrel,
this one covers the 3/4" to 1" range. When I check it against the ring
gage it's reading high by 0.0003" so I'm guessing there must be some
way of rotating the barrel or the spindle to compensate, but It does
not seem obvious what to adjust. Anyone play with one of these?

[DoN. Nichols]

Not with those, but look near the head for a hole for a
micrometer pin spanner type of thing for rotating the OD of the shank.
This is what is on my B&S/Tesa mechanical digital micrometer.

In the B&S/Tesa tri-mics there is a setscrew which allows the
thimble to be rotated IIRC.

Good Luck,
DoN.

--
Email: <dnic...@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

[oldjag]

On Feb 28, 6:01 pm, "DoN. Nichols" <dnich...@d-and-d.com> wrote:

> On 2010-02-28, oldjag <msmith5...@comcast.net> wrote:
>
> > I have several Bowers Boremikes, on one of them the zero is off by
> > 0.0003".  I bought these used and have no manuals.  They are the
> > mechanical type with the plastic window over the micrometer barrel,
> > this one covers the 3/4" to 1" range. When I check it against the ring
> > gage it's reading high by 0.0003" so I'm guessing there must be some
> > way of rotating the barrel or the spindle to compensate, but It does
> > not seem obvious what to adjust.  Anyone play with one of these?
>
>         Not with those, but look near the head for a hole for a
> micrometer pin spanner type of thing for rotating the OD of the shank.
> This is what is on my B&S/Tesa mechanical digital micrometer.
>
>         In the B&S/Tesa tri-mics there is a setscrew which allows the
> thimble to be rotated IIRC.
>
>         Good Luck,
>                 DoN.
>
> --

>  Email:   <dnich...@d-and-d.com>   | Voice (all times): (703) 938-4564

>         (too) near Washington D.C. |http://www.d-and-d.com/dnichols/DoN.html
>            --- Black Holes are where God is dividing by zero ---

I found two 0.050" hex set screws that when backed off allow the
shroud and plastic window over the barrel to be removed. Under the
shroud was another 0.050" hex set screw that locks the barrel for the
zero adjustment. Nice tool, has a decent reach, and reads right to the
inside corner of a blind hole if needed.

Thanks.