On 2008-08-02, Terry Coombs wrote:
[ ... ]
Well , the taper attachment is coming along nicely . Got the mount
brackets and base plate mostly made , got the guide rod (3/4" O1 drill rod)
and the rod slider fit to each other , just needs a minor lapping for final
fit . Having a mill has made this a bunch easier !
I'll bet.
Questions , how are they usually calibrated , inches per foot or per inch
? I have an adjustment screw arrangement calculated that will give me a
taper of .005" per inch per side per (adjustment screw) revolution , or I
can set it up for a per-foot basis .
Hmm ... Mine has two calibrations -- one end is degrees, and the
other is inches per foot.
My other question , how long is long
enough ? I'm currently setting it up for an overall (lengthwise) travel of
about 16 inches more or less . That's a bit longer than most of the ones I
looked at for this size lathe while researching . I'm concerned about flex
in the guide rod ... and hope that 3/4" is stiff enough for this length .
Mine is something like 10" travel IIRC. Do you really *need*
more for what you are doing? And at that size, the bar is about 1-1/2
wide (the stress direction), perhaps 3/4" tall, pivoted at the center,
and clamped down at both ends, so the effective length between supports
is closer to 5 inches. Based on that, a 3/4" round rod will be *way* to
flexible -- even at the 10" length which mine has, and a lot worse on
the 16" which you are planning.
There is a block which straddles the bar with a fairly
respectable surface area.
If you want to see what mine looks like, check out:
http://www.d-and-d.com/misc/MANUALS/...hment-7515.pdf
Download it and print it, since it is a scan of an old manual from
Clausing, and it takes forever to display -- so just wait once for your
printer to handle it, and then you can turn pages quickly. :-) It is a
total of four pages.
Note that I only use the calibrations on the ends for getting
close. Then I move the carriage a precise distance along the bed while
measuring the cross-slide travel -- while pulling back on the toolpost
to take the slack out of everything. This one came from an eBay
auction with only a guess that it would fit -- and a few parts which I
had to make once I figured out how it worked. If I had had the model
number (data plate fully worn off) I could have asked them for the
manual much sooner. :-)
This project is driven by my need for adjustable laps to recondition
bearing races (loose rollers with thrust washers ... what fun !) in a 1939
Harley I'm rebuilding . They just don't make the tools I need ... for less
than a Sultan's Ransom . And some they just plain don't make anymore .
So -- how long a taper do you need to make to produce these?
Let that guide you -- with a bit of extra travel to make the setup
measurements good. If you only need say three or four inches of taper,
go for perhaps 6" or maybe 8".
Good Luck,
DoN.
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