In article ,
Ned Simmons wrote:
In article ,
says...
(DoN. Nichols) writes:
*Tapped* hole? You mean that the wheel threads onto the shaft?
How do you tap it? In the lathe, just after drilling, while still on
the faceplate? If you go to a drill press, you're introducing an
additional place where error can come in.
The wheel is drilled and tapped on the lathe.
[ ... ]
I haven't read this whole thread, so may have missed some
important bit, but if I were doing this, I'd think about
making a shaft something like this:
http://www.suscom-maine.net/~nsimmons/HurdyShaft.jpg
*Nice* rendering!
The wheel would have a tapered socket (possibly in a piece
of steel or brass epoxied into the center of the disc) to
match that on the shaft. A nut on the thread would pull the
disc onto the taper. If the angle on the taper is steep
enough (depends on the coeff of friction between shaft and
socket), it will be self releasing or require only a light
tap to release.
That sounds good to me. If fitted to something like that, it
should be very repeatable on any refitting. Of course, the making of
the shafts in reasonable quantities (e.g. onesey-twosey per setup) would
be a bit of a pain -- especially on a small machine. A bit of a runout
gap between the threads and the taper would be a bit easier to handle on
a non-CNC machine, and getting the taper just right might also be a
pain. (It looks short enough to do on the compound, so if you did a
wheel and a shaft with the same compound setup, that should work --
until the next batch which might be different if the compound setting
were to be changed for other work. (E,g, for cutting the thread. :-)
You could have both the taper and thread in the socket,
eliminating the need for the nut, and also supplying the
means to push off the taper, but then it seems the thread
may be more likely to influence the runout.
It also might be hard to start to unscrew, since you've got the
taper fighting you.
Might be worth
a try.
Surface grinder wheels are often mounted on arbors similar
to this.
Is that why you had the neatly rendered shaft image handy, or
did you do this just for the reply?
Enjoy,
DoN.
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