Spindle - Slide Sychronisation

[depronman]

I know this is an old thread but I have just finish a retro fit of an ORAC with LinuxCNC and have all working including threading using the original orac encode wheel 48 slot and three optical readers so operating in quadrature
Let me know if you need any help
Paul

[Doddy]

Paul, When I'm back in the country I'll be wiring up an encoder for my lathe - I might well be in touch!

[depronman]

OK understood
I bought a encoder just in case the home made encoder was not up to the job but it meant making up a lay shaft to run the encoder and a set of timing pulleys to run the lay shaft at spindle speed. All very doable but the original ORAC encoder disc was looking me in the face so a bracket was designed in CAD to mount the 3 optical seasons with each sensor adjustable in radial position. The bracket was in two halves as it was to be 3D printed effectively a plate to hold the three sensors and adjusters and a separate stem that mounts to the lathe headstock
The two pieces are checked for position and then glued in place using cyno
Wire up the three sensors to the bob and and give it a try
The sensors have an led that flashes when the signal to the bob is triggered so rough adjustment of the sensor alignment was done using the LED on each sensor
One sensor reads the long slot to single pulse per rev
The other two read each slot and the alignment of these is rather more critical which I did with the spindle running and monitored the spindle speed in linuxcnc
It was showing on the display as varying by a few hundred rpm which it clearly was not but after redial adjustment of the two inner sensors the speed stabilised to a steady reading. The sensor mount screws were nipped up and threading on a test bar M10x1.5 attempted
To my amazement it waited the G04 P10 that I programmed in G76 then performed 15 cuts and 2 flex passes with no cut
The thread was nut deep enough so x touch off adjustment made and run again. To my amazement it picked up the thread perfectly and only made a cut after 13 passes of cutting air
Retired and nut still not quite going on
Further adjustment made and run again this time nut ran down the thread perfectly with just a slight amount of slop same feel as the nut on a commercial set screw
I cut the first thread 30mm long
Once depth was correct I cut another thread 9 mm long and the nut ran alway down the thread first time the feel of the nut is the same from first turn through the middle to the very end
Well please with the little ORAC my home brew encoder and linuxcnc

I never do manage to get mach3 to thread on a Boxford BUD I converted to cnc
It may be getting linuxcnc in the near future!!!

all the best. Paul