Sherline Lathe Conversion ?

No eBay APP ID and/or Cert ID defined in Kunena configurationNo eBay APP ID and/or Cert ID defined in Kunena configuration

currinh wrote: The encoders I've run across on E-Bay are in the $200 range, a little pricey for this conversion.

This one is £17


There are cheaper ones, but they don't tend to have the index (The Omron above does):

Andy:

I guess my search abilities have gone south. When Iron-Man posted I did a quick e-Bay search and only found expensive ones. The one you found is about $26 US. It's listed at 1000 P/R (pulse per rev) which I think is too high, if my calcs above are right? Please let me know if I've missed something there.

I looked again and found this one, E6C2-CWZ6C 60P/R, also from Omron . It's more at $55 US but this is within the budget and would be sooo much easier to incorporate.

These two Omron encoders both have an "NPN Open Collector Output" according to Omron . To hook these up to a parallel port I'd follow the same configuration as for the optical switch, using a pull up resistor? I believe the Gecko 540 directly ports its input pins through to the parallel port.

Thanks again for the help.

Hugh
Klamath Falls, OR, USA

currinh wrote: These two Omron encoders both have an "NPN Open Collector Output" according to Omron . To hook these up to a parallel port I'd follow the same configuration as for the optical switch, using a pull up resistor?

I think you can connect NPN OC directly to a parallel port pin, but if you are going via a BoB you are likely to need a pull-up to source the current. The encoder output can be considered as a switch to GND, and I think would go on the low side of an opto-coupled BoB input normally.
en.wikipedia.org/wiki/Open_collector

Hugh if you search long enough sometimes, you can find the Allen Bradley (heavy duty) encoders real cheap, sometimes new. Make sure that you consider the timing belt, pulley diameters and shaft size in your design.

Iron-Man

Andy: I ordered the Omron E6C2-CWZ6C 60P/R encoder. It should be on the slow boat from China soon.

I've been thinking of the interface to a parallel port, but that is not the case. The Gecko G540 is doing some interfacing and I'm not sure, from the manual, just what. I emailed Gecko but they haven't gotten back to me. The manual shows the G540 input switches (i.e. limit switches) directly switching the input pins to ground. I have a G540 so I measured an input pin to ground. Open voltage is 11 V and the shorted current is 7 mA. I think it should be OK to directly connect the encoder or slotted optical switches, both open collector, directly to the G540. We'll see when the parts show up.

Iron-Man: As I said, I ordered the e-Bay encoder from China. Right or wrong we'll see if it works.

I want to see the encoder before going too far with the mounting design. I have some XL pinion stock what I plan to cut the pulleys from. Likely just use a set screw on the encoder pulley and screw the spindle pulley to the Sherline pulley using a bolt circle. That's the plan but haven't looked at sizes yet. Worse comes to worse I'll order two pulleys and a belt from SPD/SI. Should be OK as long as the two pulleys are the same diameter / # teeth.

Thank you both for your help. Great instructions and I haven't even gotten to the Linuxcnc configuration yet.

Thanks.

Hugh
Klamath Falls, OR, USA

currinh wrote: I want to see the encoder before going too far with the mounting design. I have some XL pinion stock what I plan to cut the pulleys from. Likely just use a set screw on the encoder pulley and screw the spindle pulley to the Sherline pulley

I have wondered if a speedometer drive would work:

www.beedspeed.com/images/Speedo_drive_kit_metal.gif

The problem would be to find one that was exactly 1:1, but the dissimilar sizes of driver and driven might be useful.