G'day Johm
Your proposal would work, but I would make two mods as I am concerned
the shaft may be difficult to release. Firstly I would cut a groove
at the point where the hacksaw cuts end, this will focus the bending
to this point. Secondly I would have turned the end to a slight
taper, a few thou thinner at the end so that when the wedge nut is
released the expanded part would contract to under the shaft diameter.
I haven't considered the bolt but would probably use a commercial
product. My local hardware store sells a range of 8mm metric bolts up
to 150mm long, they are not high tensile but are forged ane quite
tough. Most hardware stores have a range of imperial threaded rod
available up to 1/2" diameter, I think the thread is Whitworth.
I don't see any difficulty cutting an 8mm thread as I have already
cut a 3/8 x 24 thread plus smaller metric threads successfully. I
found I could do it under power and didn't meed a crank or handwheel;
you do need to design a runout groove for the thread cutting tool
when cutting to a shoulder and have you whits about you.
Regarding the coned nut or end, I don't see any need to pin it to the
shaft, friction is a mighty thing!
Anyhow, all this is hyperthetical and for me about 3 projects away.
One good turn deserves another.
Regards
Ian
--- In 7x12minilathe@..., "born4something" <ajs@...>
wrote:
Hi Ian,
I have seen bike handlebars done that way. My thoughts on such a
locking mechanism were more on a par with a masonry bolt. Slit your
close fitting shaft - even crudely with a hack saw - at every 90
degrees say. Then turn a cone shape to partially sit inside your
close fitting shaft as a spreader. Tap at 8mm for the draw bolt.
That should eliminate any misalignment during tightening. In either
case, during removal you need to loosen the 8mm bolt but NOT use it
to pull the close-fitting shaft out of the spindle as that would
tend to re-lock it.
Just a thought. Both approaches lend themselves to reversal. Turn
the 8mm bolt around and use an off-the-shelf nut on the outer end.
Key the inner end to the cone or wedge section by milling a slot or
pinning. This avoids cutting a long thread with any associated
angst. It also means both bolt & nut can be high tensile with
little
chance of ever stripping and easy replacement anyway. Or were you
figuring on cutting the 8mm thread in the lathe?
