More encoder stuff
Posted: Tue Oct 17, 2017 12:23 pm
With all the encoder stuff that's going around I thought I'd throw this in for what it's worth.
My trusty old Mach3 equipped Denford ORAC is being converted to Acorn. I'm determined to end all those years of one pulse per rev threading once & for all! An internet friend hooked me up with a medium duty Heidenhain 2000 line encoder & its mounting was completed over the weekend.
There are a couple of things to think about for you fellers that have one on the way. Go ahead and order your wire from Centroid if you're going to roll your own. I had trouble finding what I thought was the right stuff and didn't think to look there. I got 22awg, 8 conductor stranded with shield & drain wire for a good price on ebay but didn't know 'til it got here that it was 8 individual conductors, not 4 pair twisted. I'm going to use it anyway because the cable length is so short.
There was a bit of putzing around deciding on timing pulleys. The one on the spindle had to be large enough in diameter to encircle the spindle and still have enough "meat" in the hub to allow boring to fit plus finding one that was available easily (cheap) & quickly. It ended up being a 40 tooth XL on Amazon Prime. I like GT3 better but big ones are harder to source quickly.
The 4mm encoder shaft needed an adapter to fit the 20mm pulley bore. I put 4 set screws in the adapter to allow tweaking it for minimum runout. I don't have a 4mm reamer & the closest drill I had is a couple thou over. You wouldn't think runout wouldn't be that important but I found when adjusting the belt tension that a little runout goes a long way & the cyclic tension change might shorten encoder life. I made the mount to allow easy adjustment using the original encoder flange mount. Sorry for the diarrhea of the keyboard but it may be a help to some other encoder challenged soul out there.
Here's a couple pics. Anybody wanna buy a really good single slot index wheel & a CNC4PC C-3?:)
My trusty old Mach3 equipped Denford ORAC is being converted to Acorn. I'm determined to end all those years of one pulse per rev threading once & for all! An internet friend hooked me up with a medium duty Heidenhain 2000 line encoder & its mounting was completed over the weekend.
There are a couple of things to think about for you fellers that have one on the way. Go ahead and order your wire from Centroid if you're going to roll your own. I had trouble finding what I thought was the right stuff and didn't think to look there. I got 22awg, 8 conductor stranded with shield & drain wire for a good price on ebay but didn't know 'til it got here that it was 8 individual conductors, not 4 pair twisted. I'm going to use it anyway because the cable length is so short.
There was a bit of putzing around deciding on timing pulleys. The one on the spindle had to be large enough in diameter to encircle the spindle and still have enough "meat" in the hub to allow boring to fit plus finding one that was available easily (cheap) & quickly. It ended up being a 40 tooth XL on Amazon Prime. I like GT3 better but big ones are harder to source quickly.
The 4mm encoder shaft needed an adapter to fit the 20mm pulley bore. I put 4 set screws in the adapter to allow tweaking it for minimum runout. I don't have a 4mm reamer & the closest drill I had is a couple thou over. You wouldn't think runout wouldn't be that important but I found when adjusting the belt tension that a little runout goes a long way & the cyclic tension change might shorten encoder life. I made the mount to allow easy adjustment using the original encoder flange mount. Sorry for the diarrhea of the keyboard but it may be a help to some other encoder challenged soul out there.
Here's a couple pics. Anybody wanna buy a really good single slot index wheel & a CNC4PC C-3?:)
