continuation of the "References: " header, which is growing long
enough so it is likely to start creating problems, so I've
moved this part to the body.
On 2009-07-08, Michael Koblic wrote:
"DoN. Nichols" wrote in message
...
[ ... ]
I somehow asumed that it was not a done thing to bore out the *finished*
pulleys as they make the plain pulleys that *are* meant to be bored to
specs.
Looking at the 57105K3
You mean 57105K33?
Must have clipped it pasting.
That happens.
That is acetal with an aluminum hub, which
would be too weak to handle that kind of treatment -- or the kind of
loads involved. Steel would be better (and more expensive, of course.
:-) Perhaps Acetal for the smaller end pulley, and steel for the larger
end on the lathe's spindle.
the hub is 7/8" which after boring to 5/8" ID
would
leave walls 1/8" thick. You think that is all right? The 6495K733 is
steel
and has a 1.5" hub.
Put more information about the pulleys. I'm going to have to go
back to McMaster Carr's web site and print out that page.
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,
which is what I use for browsing, newsreading, and for e-mail.
I won't allow a Windows system to touch the outside net from my
network. It is too easy to have one get a virus and then start
spewing out spam to the world, giving my network a bad name.
2) Tabs (which I do have in the Opera browser which I use by
choice) would only help if I were doing both the catalog
checking and the news editing on the browser at the same time.
I *don't* and *won't* use a browser as a newsreader -- I use a
*real* newsreader (better than any implementation in a browser)
and don't use Google for accessing news.
3) Scrolling around on the catalog page using a browser is not as
easy nor as quick as printing out the catalog page and scanning
it beside my keyboard. (Among other things, in the browser, I
have to scroll back up to find out what the column headings are,
and sometimes all the way to the top
[ ... ]
And you won't want to be stepping up speed to the spindle, so
the larger pulley will be on the spindle, thus with the largest hub
diameter too.
Or -- go for the taper-lock type hubs where you can change hubs
to fit the shaft once you have the right pulley.
Presumably you are referring to something like this: 6495K222. The cost
is
getting up there.
No -- those are cylindrical bores. Look at "57095K11" -- and in
particular "57095K112" which is for a 5/8" shaft. But the problem is
one of finding the right timing pulleys to fit. These are for larger
belts ('H' (heavy) series, not 'L' or 'XL'.)
I thought the 57095K11 is a bushing used with a sprocket, not a pulley per
se.
I've seen the same type of bushings used on timing belts, and
actually *have* some on my CNC Bridgeport.
The 6495K222 is used with 6086K14 quick disconnect bushing which is
available with a 5/8" bore. But the bushing and pulley combo is close to
$100.
I didn't find the bushing itself, and could not see how well it
would work for this task. I *wish* that McMaster Carr would make their
catalogs more readily available.
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.
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 accurte 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.
[ ... ]
http://www.milesfaster.co.uk/gallery...k/sun-dial.htm
Hmm ... I'll bet that was not made on a lathe, but rather formed
up from stainless steel, and welded into shape. If it were solid enough
to turn on a lathe, the supports probably would not hold it. :-)
But one has to walk before one can run. Also one must consider the size
of
the etching bath, how many gallon bottles of Ferric Chloride one would
need,
The markings on that one were welded onto the stainless steel
surface, not etched into them. As the scale goes up, the production
means must change.
Please! I do not just copy other people's work!
A good stainless steel won't etch with the Ferric Chloride
anyway, so you'll need some other way to attach the number markings to
something of that size designed for outdoor exposure. I was talking
about how it made sense to make it -- not how to copy someone else's
work. You could form the letters with weld markings, or rivet them in
place, or any of a number of other possibilities.
Well, not too often. 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. :-)
Enjoy,
DoN.
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