Dipping my toes into turning

[Jim F]

Someone correct me if I'm wrong here as I have never cut a set of metric threads.
But my guess is the same 29 degree included angle of that thread Type covers both US - (imperial?) and metric too.
Most any lathe will cut acme threads.
That has to do with the shape of the tool and the angle of the compound rest. They'll cut V sharp, ANS, acme, square and who knows what other types of threads there are.
Whether it will cut imperial, metric, or both Pitches is the question.
I'd guess most of those off shore machines will cut both.

Depends on leadscrew pitch, a 100/127 gear is needed to cut both.

 

[OTmachine]

Yes, metric threads are the same 60 degree included angle as American. I believe Whitworth threads are 55 degree included, (used to be used on Norton M/C).

 

[davidpbest]

Depends on leadscrew pitch, a 100/127 gear is needed to cut both.

It's all explained in the attached.

 

[koenbro]

Someone correct me if I'm wrong here as I have never cut a set of metric threads.
But my guess is the same 29 degree included angle of that thread Type covers both US - (imperial?) and metric too.
Most any lathe will cut acme threads.
That has to do with the shape of the tool and the angle of the compound rest. They'll cut V sharp, ANS, acme, square and who knows what other types of threads there are.
Whether it will cut imperial, metric, or both Pitches is the question.
I'd guess most of those off shore machines will cut both.

This is of great interest to me because I already have some thoughts about threads I want to cut. On my mill I almost never cut threads with a traditional tap even though I unwisely bought that expensive springy Tormach holder. Since learning how to threadmill (from NYCCNC's videos on Youtube), I can cut almost any thread with just two thread mills, and adjust them to looser/tighter fit. In particular I like to cut NPT for various air fitments. For M4-M6 I still rely on a conventional tap as my smallest threadmill does not go that low, but will get a threadmill for those.

So am looking forward to the opportunity to cut male threads on the lathe, plus the option to do left-handed threads, etc

 

[koenbro]

OK I have placed an order for an Eisen 1340 GHE.

Already looking at a Clough42 electronic lead screw controller. Not sure what motor to use and his experience with the $100 stepper-killer killer which cost him $200 plus a huge headache to set up, tune, match drivers and manuals to still have a motor proven to have a short life is not appealing. I think I am going with Teknic Clearpath.

The lathe probably comes with a BXA toolpost. Can anyone please recommend toolposts in the premium-minus tier? I mean the professional grade would be Aloris and Dorian, but what is the one level just below? Something I can get from MSD Direct or reputable US dealers. I am not interested in Alibaba or other Chinese sources.

 

[RJSakowski]

I went with a Stepper Online NEMA 24 4.25 N-m hybrid stepper and driver package. I used a 1:1 pulley ratio from the stepper to the lead screw gear box on my G0602. I found the torque somewhat lacking so I set the gearbox for a 2:1 reduction which has proven to work with no issues. I began with a 36 volt power supply but upped the voltage to 42 volts which also improved performance.

IIRC, my total cost came to a little over $200.

 

[koenbro]

I went with a Stepper Online NEMA 24 4.25 N-m hybrid stepper and driver package. I used a 1:1 pulley ratio from the stepper to the lead screw gear box on my G0602. I found the torque somewhat lacking so I set the gearbox for a 2:1 reduction which has proven to work with no issues. I began with a 36 volt power supply but upped the voltage to 42 volts which also improved performance.

IIRC, my total cost came to a little over $200.

That sounds very attractive. Do you happen to have the model number or a link to the specific motor?

 

[RJSakowski]

That sounds very attractive. Do you happen to have the model number or a link to the specific motor?

I do but it was no longer available shortly after I bought mine. 24HS40-5804D-E1000 Full Datasheet Nema 24 Closed Loop Stepper Motor 4.25Nm/601.97oz.in Encoder 1000CPR - STEPPERONLINE - 24HS40-5804D-E1000.pdf
24HS40-5804D-E1000 TorqueSpeed Curve.xls - 24HS40-5804D-E1000_Torque_Curve.pdf

 

[Huub Buis]

All closed loop (stepper, hybrid, servo, etc) need tuning. To keep things simple to start with, I would go for an open loop stepper motor and digital driver.
I run both my CNC lathe's and CNC router using 1.26 Nm open loop steppers and never felt the need for more power.

Stepper motors deliver constant power and lose torque (twice the RPM is half the torque) as the RPM rises, that is normal behavior. If you really want that much power to start with, I would go for an AC servo motor (constant torque at "all" RPM) and adjust the gearing so the motor will deliver it's full power at the max speed you want your Z-axis to run.
Beware, that once you have a motor on your Z-axis, the 2 half nuts will be used all the time and to much load will wear them down.

 

[koenbro]

All closed loop (stepper, hybrid, servo, etc) need tuning. To keep things simple to start with, I would go for an open loop stepper motor and digital driver.
I run both my CNC lathe's and CNC router using 1.26 Nm open loop steppers and never felt the need for more power.

Stepper motors deliver constant power and lose torque (twice the RPM is half the torque) as the RPM rises, that is normal behavior. If you really want that much power to start with, I would go for an AC servo motor (constant torque at "all" RPM) and adjust the gearing so the motor will deliver it's full power at the max speed you want your Z-axis to run.
Beware, that once you have a motor on your Z-axis, the 2 half nuts will be used all the time and to much load will wear them down.

I am very comfortable with the tuning process from having converted my manual mill to CNC. I used Teknic SDSK motors and have tuned them many times. I even have an extra NEMA 23 motor that I purchased for the 4th axis that I have not yet implemented. So am thinking of using it. Will need a power supply, and while the Teknic one is expensive and needs an extra power hub that setup will be handy if I ever decide to convert the lathe to CNC.

Would not imagine using my mill in manual - can still drive each axis in manual with the pendant control but once you get used to complex shape, threadmilling etc I don't want to go manual .