On Wednesday, February 15, 2012 04:04:27 PM Steve Blackmore did opine: > On Wed, 15 Feb 2012 06:45:34 -0500, you wrote: > >On Wednesday, February 15, 2012 06:35:36 AM charles green did opine: > >> get a CD that > >> you dont want to listen to anymore, and cnc it out of that. and then > >> paint it black. > > > >Now that might be (the old cd) a usable idea. I probably bin a 50 pack > >a year of those, old data & distro's going obsolete mostly. And that > >should be cheap enough even if I use a fresh cdr to serve as a test > >developing tool. I don't recall ever seeing a cd get hot enough to > >warp either. I can fine tune it 5 thou here, and 5 thou there to > >optimize the design very easily. > > Gene - the encoder wheel I use is 3mm Tufnol sheet, painted black. > Cheap, flat and easy to machine. I fitted an aluminium hub with a keyway > to engage the key on spindle shaft. It's simply sandwiched up against > the pulleys with a collar. > > Steve Blackmore
The plastic, except for temporary fitting wouldn't do for permanent as it will be trapped between the spindle preload nut, and it's locking nut in normal operation. That is driven tight with a drift punch in the nut slots. The plastic will 'cold flow', loosening the nut, and that won't be good for things. I've been fooling with that bit of postscript, adjusting it to arrive at a fit, but for slot type opto's its not as good a deal as it would be with reflectance types as it appears to be best done with the opto's arranged in a radial line as opposed to having the slot types in a straight line. The radial line would have the advantage that the quadrature is fairly well fixed in that case as opposed to using a single high frequency track being watched by 2 opto's whose spacing would be trimmed a bit to hit the needed quadrature on the o-scope. Because the postscript puts the index marker inside the main track it would make sense to just increase the depth radially of one slot & let the center opto device become the Z signal since it's tracking a smaller circle. The problem then might be better handled by further modifying the gcode I have so instead of an index slot in the rim, just extend one slot inward radially far enough to make the B the Z and vise-versa. The center opto then would need to be pushed sideways a bit to get the actual index edge to be centered in the A+B=(1 or 0 state) in order to get a true index edge. That will be investigated too, but I have got to get off my butt and go burn some sugar, a 2 gram breakfast muffin just put me north of 300, not good at all when ones breath smells like acetone so I'm killing both my feet and my kidneys. Dammit, I need bits to get me busy & they are still 2 days away. Sigh. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> Barth's Distinction: There are two types of people: those who divide people into two types, and those who don't. ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
