On 2009-07-09, Michael Koblic wrote:
DoN. Nichols wrote:

[ ... ]

Or get Explorer 7 or 8 with tabs.

Exactly how would that help me?

1) I *can't* run Explorer of any version on my Sun Workstation,

[ ... ]

Chacun a son gout...

After all -- I don't have to worry about the usual virus
infections with the Sun Workstation. They are all targeted at the
easiest target -- Windows. :-)

[ ... ]

The small pulley that should match it (L series) is 6495K23. This
one is steel, the bigger one is cast iron.

O.K. Cast Iron is fine for the task. It is the softer metals
like the aluminum hub, and the softer plastics like the acetal
(Delrin) body which are likely to be problems for your job.

I suspect it is all academic.

O.K. If you are considering purchasing a larger lathe (as
suggested by the questions about lubrication), yes it is more than you
need to do.

And I would not worry about boring out the larger pulley to fit.
You'll need means for measuring your bore to know when you are at
the right size -- which probably means making up a sample shaft
with a step
0.010" too small, one 0.005" too small, one the right size, and one
about 0.002" too large. Stop before the too large will fit in. And
be sure to remove the setscrews before you start boring. Hold it
by the hub in the 4-jaw, and take a lot of time tuning it to on
center before you start boring.

A telescopic gauge?

Do you have one which will go small enough? I forget whether
that or a split ball-end gauge is the better fit for that size. I've
got both -- plus some Tesa/B&S Tri-Mikes for more accurate bore
readings.

But accurate reading of either the split balls or the telescoping
gauges with a micrometer takes some experience to get accurate and
repeatable readings, which is why I suggested that you make a gauging
fixture which will be quick and easy to use, and especially to tell
you when to start sneaking up on the final dimension.

Well, it is a close run thing between using the telescopic gauge and a
micrometer and actually making something with the required accuracy. The
last two attempts at making something to a given dimension I overshot by
0.010" and 0.004" respectively. I suppose I am getting better...

Hmm ... first trick is to make sure that the tool is quite
sharp.

Second is to feed something like 1/3 the distance to reach final
diameter, make your cut, and measure what you really got, comparing it
to what you expected. Divide what is left by two, and adjust by how far
off your previous result was. Feed in that much, and make another cut
and measure again. Adjust again for the final cut.

It is difficult to get a very light cut to produce what you
want, because deflection of the workpiece and the tool may prevent ever
taking a bite, so when you finally feed enough to take another bite, it
is too big. So sneaking up on the final dimension can be difficult, and
making larger cuts works better.

As for getting the boring to work right -- bore to a few
thousandths undersized, and then use a reamer to get to final size. The
same problems with sneaking up on the size occur when boring as when
turning -- perhaps more so.

[ ... ]

Also,
if you have a hammer suddenly there is an awful lot of nails about.

But when the workpiece is the size of Big Ben, nails don't do
much good, even if you have the best hammer in the world. :-)

Maybe I shall limit myself to 12". It has served me well thus far.

O.K.

Enjoy,
DoN.

--
Email: | 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 ---