On 2014-01-15, Bob La Londe wrote:

[ ... ]

My only real issue then is getting a good bore of .4965 with the tools I
have. Reaming to .499 would be easy, but I have to bore to any off size.

Possibilities:

1) Adjustable reamer.

2) Lap to size.

3) Roller burnisher.

4) Roll up some emery paper and twist it in the bore. (How long is
the bore?

However, all three require a way to *precisely* measure the
bore. Nicest is one of the the tri-mikes of the right range. Lacking
that, a shaft with a minimal taper (e.g. 0.001/inch) and slide it in
until it stops. Mark at the edge of the hole with a felt-tip pen, pull
it out, and measure with a tenths-reading micrometer. (Likely more
repeatable than a small-hole gauge, which requires a really good feel.

Or -- perhaps set up a toolpost grinder on the lathe (with
proper protection for all sliding surfaces). Set the compound as close
as you can to 5.71 degrees (nearly parallel to the workpiece axis) and
this will allow you to move in 0.0001" for every 0.001" you turn on the
compound feed dial (assuming that the dial is direct reading -- *beware*
some compounds read half of actual motion so you know how much diameter
you will take off instead of how much radius). It makes more sense for
the cross-feed to be so calibrated, but sometimes it is also done on the
compound where it only makes sense when parallel to the cross-feed. :-)

Good Luck,
DoN.

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