6331
General Mach Discussion / Re: Problems threading on the lathe
« on: April 10, 2009, 04:18:41 PM »
Hi All,
Was off on a trip and just got back.
The "Use Spindle Feedback In Sync Mode and also Spindle Speed Averaging is checked.
The RPM displayed in the DRO will only flicker once in a while and then only within 1 rpm and
I check the actual RPM with a good speed indicator and it says 300 RPM.
The cuts were 25 passes, but total depth was only .005" to eliminate any rpm influence and never once did I notice the rpm change.
I didn't use diagnostics to see what was happening in it's RPM reading ,and unfortunately, when using the SS you don't have a take on the rpm as when using the PP and can monitor with the Turn Diagnostics.
In the latest version of threading you can no longer put a dwell before or after the pass as you were able to do in prior versions. That allowed me to take actual indicated readings on each beginning and end of the Z moves for comparison.
Just for info, no need for comment, I got a buddy who just CNC'd a lathe, has a two horse motor and when geared for like 600rpm it's probably like 5 or 6 hp, for a screw he used a 1-8 tpi of threaded rod and has 0.046" of backlash ( hardware store threaded rod and nut ) . He uses backlash compensation and does small and large threads that look like they came off a high end machine. No i haven't checked the lead on his threads , but the point is, here is a machine that should turn out crap for threads and it dosen't! Mind boggling!
Have a few thinsg to do and then will fool around some more. Want to try ART's rpm test on a few different PC's.
RICH
Was off on a trip and just got back.
The "Use Spindle Feedback In Sync Mode and also Spindle Speed Averaging is checked.
The RPM displayed in the DRO will only flicker once in a while and then only within 1 rpm and
I check the actual RPM with a good speed indicator and it says 300 RPM.
The cuts were 25 passes, but total depth was only .005" to eliminate any rpm influence and never once did I notice the rpm change.
I didn't use diagnostics to see what was happening in it's RPM reading ,and unfortunately, when using the SS you don't have a take on the rpm as when using the PP and can monitor with the Turn Diagnostics.
In the latest version of threading you can no longer put a dwell before or after the pass as you were able to do in prior versions. That allowed me to take actual indicated readings on each beginning and end of the Z moves for comparison.
Just for info, no need for comment, I got a buddy who just CNC'd a lathe, has a two horse motor and when geared for like 600rpm it's probably like 5 or 6 hp, for a screw he used a 1-8 tpi of threaded rod and has 0.046" of backlash ( hardware store threaded rod and nut ) . He uses backlash compensation and does small and large threads that look like they came off a high end machine. No i haven't checked the lead on his threads , but the point is, here is a machine that should turn out crap for threads and it dosen't! Mind boggling!
Have a few thinsg to do and then will fool around some more. Want to try ART's rpm test on a few different PC's.
RICH