Change gears? ELS? Help!

jarrettbailey

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Hello all

I just bought a Lux Cut 12x30 lathe (made in Taiwan in the early 80's I believe). It's a nice heavy machine (2000 lb). Has a foot brake and a 5hp motor. Ways looks great and everything seems good and tight, but it didn't come with change gears for metric threading. I've been trying to find them or get them made, but I'm wondering if it wouldn't be better to go with the Electronic Lead Screw I've read about here and a few other places. I'm not really a programmer or electronics master, but I can do either enough to get by as long as it's not SUPER complex. I'd really appreciate the opinions and sources (either for gears or ELS). I'm just setting up my little machining corner in my shop and I'm excited to get it going.

Thanks!

61016.jpeg
 

RJSakowski

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Whether or not to go with an ELS depends upon your situation. I installed an ELS on my Grizzly G0602 and am generally pleased with the performance. My particular reason for going that route were primarily that every change of lead screw feed required swapping gears. The ELS accomplishes that with the push of a few buttons. The only negative so far is that the available torque is somewhat anemic with the stepper motor I have chosen. My cost was a little over $200 for the modification although I used several components that I had on hand.

The 602 uses a single screw for both feed and threading and the ELS that I chose was developed for that lathe. Your lathe is significantly larger and, will require a larger stepper or servo motor to better match the capabilities of your lathe. The gear belt drive would have to be beefed up as well. On that basis, your cost would probably be running in the $500 range.

Your choice would depend upon what is needed to provide your desired capability. If you have a complete set of change gears less the inch/metric tooth pair you may be able to find those gears from another lathe manufacturer. For example, the Grizzly G4003 uses a 91t/86t combination to convert from inch to metric and the part cost is $81. If the gear modulus is the same as for your lathe, this would be a possible solution for you. You can determine the modulus of your gears by dividing the O.D. in mm. by the number of teeth +2.

Another reason favoring an ELS would be convenience. If changing thread pitch requires a change of the external change gears that becomes tiresome fast. Your lathe, having separate drives for power feed and threading would be less of an issue but it's your choice.
 

jarrettbailey

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I appreciate it. It looks like I am missing several of the gears however. I'd rather get change gears made if I can honestly. I like to keep things simple. Do you know of any sources for getting these made?
 

ErichKeane

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I appreciate it. It looks like I am missing several of the gears however. I'd rather get change gears made if I can honestly. I like to keep things simple. Do you know of any sources for getting these made?
If you know the module, you could likely just buy a bunch from boston-gear, and potentially have to broach out the center.

Alternatively, if you have a mill and a dividing head or rotarytable that can be put on its side, you can make your own!
 

RJSakowski

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Determine the modulus as described in post#3. Then determine what you need regarding the number of teeth. Finally, you need to determine ythe pressure asngle of your gear set. Any gears with the same modulus and pressure angle will mesh.

Can you determine which gears are missing. Alternatively, what gears do you have. From your threading chart, you will be able to gfigure out what you need. The most common transposing gears for converting inch to metric are 127 and 120. However the 91 and 86 gears differ from the exact ratio by less than .02%.

Once you have determined what you need, you can start looking at parts lists for similar sized lathes. You may have to rebush the gears but that is a relatively easy task.
 

FLguy

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If you go ELS look at Rocketronics from Germany. I just finished installation on my lathe. Happy so far. Also a very supportive company. Quick to reply to your questions.
 

GunsOfNavarone

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Whether or not to go with an ELS depends upon your situation. I installed an ELS on my Grizzly G0602 and am generally pleased with the performance. My particular reason for going that route were primarily that every change of lead screw feed required swapping gears. The ELS accomplishes that with the push of a few buttons. The only negative so far is that the available torque is somewhat anemic with the stepper motor I have chosen. My cost was a little over $200 for the modification although I used several components that I had on hand.

The 602 uses a single screw for both feed and threading and the ELS that I chose was developed for that lathe. Your lathe is significantly larger and, will require a larger stepper or servo motor to better match the capabilities of your lathe. The gear belt drive would have to be beefed up as well. On that basis, your cost would probably be running in the $500 range.

Your choice would depend upon what is needed to provide your desired capability. If you have a complete set of change gears less the inch/metric tooth pair you may be able to find those gears from another lathe manufacturer. For example, the Grizzly G4003 uses a 91t/86t combination to convert from inch to metric and the part cost is $81. If the gear modulus is the same as for your lathe, this would be a possible solution for you. You can determine the modulus of your gears by dividing the O.D. in mm. by the number of teeth +2.

Another reason favoring an ELS would be convenience. If changing thread pitch requires a change of the external change gears that becomes tiresome fast. Your lathe, having separate drives for power feed and threading would be less of an issue but it's your choice.
I'm concerned @RJSakowski , I have most the parts, just waiting for the encoder from China. I have copied Clough42's design down to the minute detail. I did the same with the VFD and I will say, I was internal threading aluminum the other day and I could visibly see the initial struggle the machine had when the tool contacted the material. We're talking a .002 pass here. So, back to my concern, you had mention how anemic it seemed. I'm not sure I can accept the lack of torque (at some speeds) on the VFD and now same situation on the ELS. I was wondering if I reinstalled the motors timing belt, and used a different gear set AND perhaps used different gearing on the Stepper/servo on the ELS if the weaknesses could be addressed. Hopefully this is of value to the O.P.
 

RJSakowski

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I'm concerned @RJSakowski , I have most the parts, just waiting for the encoder from China. I have copied Clough42's design down to the minute detail. I did the same with the VFD and I will say, I was internal threading aluminum the other day and I could visibly see the initial struggle the machine had when the tool contacted the material. We're talking a .002 pass here. So, back to my concern, you had mention how anemic it seemed. I'm not sure I can accept the lack of torque (at some speeds) on the VFD and now same situation on the ELS. I was wondering if I reinstalled the motors timing belt, and used a different gear set AND perhaps used different gearing on the Stepper/servo on the ELS if the weaknesses could be addressed. Hopefully this is of value to the O.P.
Unlike the stepper/servo, the VFD loses torque with decreasing speed. The issue that I have with a VFD is the loss of torque at low rpm. My Tormach has a 1hp phase VFD and is practically useless when operating at the low rpm limit which is around 12% of the nameplate rpm.

If/when I convert my lathe to a VFD drive, I will retain the OEM pulley arrangement to take advantage of the torque multiplication.

As to the ELS, I found that I could generate 110 lbs of force at the carriage with a feed rate of .1"/rev. @ 173 rpm. My setup is different than Clough's. He used a servo and 3:1 pulley reduction on his servo drive. I am using a hybrid stepper with a 2:1 gear reduction. As, I recall, he ended up with a stall torque of around 900 oz-in. at the lead screw whereas I have around 1200 oz-in..
https://www.hobby-machinist.com/threads/electronic-lead-screw.76101/page-10 post # 282
 

GunsOfNavarone

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I am using the servo/stepper setup (is this not a hybrid of the two?) Are you saying that the 2:1 pulley setup is a stronger/torquier setup? I'd rather make the small changes now before it all is put together in the machine. Sounds like I should also use a different pulley setting. I was excited for that 50 rpm threading speed, but I was kicking its butt at 130rpm
 

GunsOfNavarone

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I am using the servo/stepper setup (is this not a hybrid of the two?) Are you saying that the 2:1 pulley setup is a stronger/torquier setup? I'd rather make the small changes now before it all is put together in the machine. Sounds like I should also use a different pulley setting. I was excited for that 50 rpm threading speed, but I was kicking its butt at 130rpm
 

RJSakowski

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I am using the servo/stepper setup (is this not a hybrid of the two?) Are you saying that the 2:1 pulley setup is a stronger/torquier setup? I'd rather make the small changes now before it all is put together in the machine. Sounds like I should also use a different pulley setting. I was excited for that 50 rpm threading speed, but I was kicking its butt at 130rpm
What is your lathe? Are you using the same hybrid motor tha Clough used? Using a 2:1 pulley arrangement will double the output torque but also double the required motor speed to obtain a given lead screw feed. Steppers typically have an inverse relationship between rpm and pull out torque but there is also a bit of a plateau at low rpm due to the limitation of drive current. Here is the torque curve for my stepper. If my stepper is running at 150 rpm, there is about 300 N.cm of torque. If I double the speed, the torque drops to around 260 N.cm but the 2:1 pulley reduction to give me the 150 rpm on the output doubles that torque to 520 N.cm for a 73% increase in available torque
 

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GunsOfNavarone

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RJ, I have the G0602 as well, the stepper & driver are verbatim what Clough used. If there are logical/worthwhile changes I can make, now would be a good time. I have the launch board programmed and up and running. I have everything except one pulley and the encoder which are in route. Perhaps there will be no issues, but again, this would be the time before I start making mounting brackets and such....
What are you thoughts of belts/pulleys for the VFD? Like I mentioned I removed the ribbed belt from the motor and am using the center pulley from the motor to the spindle. What are your thoughts to improve torque?
 

RJSakowski

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RJ, I have the G0602 as well, the stepper & driver are verbatim what Clough used. If there are logical/worthwhile changes I can make, now would be a good time. I have the launch board programmed and up and running. I have everything except one pulley and the encoder which are in route. Perhaps there will be no issues, but again, this would be the time before I start making mounting brackets and such....
What are you thoughts of belts/pulleys for the VFD? Like I mentioned I removed the ribbed belt from the motor and am using the center pulley from the motor to the spindle. What are your thoughts to improve torque?
Seriously, you will want to take a look at some of your overhead losses. If you haven't already done so, the half nut setting is a quick and easy fix. We had some communication on this back in November. https://www.hobby-machinist.com/threads/grizzly-g0602-half-nut-engagement.80832/#post-717716 If you find that you have torque issues, you can run the internal gear box in position IC instead of IA. This will double your servo rpm and double the output torque. You will have to change the thread pitch setting from 12 tpi to 24 tpi to compensate.

I would recommend mounting your servo motor under the lathe bed as I did with mine rather than Clough's location. I was able to fit a NEMA 24 motor in that space so a NEMA 23 motor will fit easily. I had to open up the opening some which took a bit of effort but it makes for a much cleaner install. My control box is actually quite similar to what Clough used. I just repurposed an old mains fuse box. I didn't use bulkhead connectors on the box as all the the internal connections are easily broken should the need arise.

I would recommend using the highest voltage power supply consistent with your driver. If you are using a switching powers supply, you should run a voltage about 10% lower than the maximum driver voltage. This is to prevent back emf from tripping the over-voltage circuit.
 

GunsOfNavarone

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I will look at the half nut, honestly since it works, I have no way of deciding if it's tight or just right. Anyway of knowing/testing?
If I found that with Clough's ELS I need more torque, you're saying to run the gears at I/C but go into the code and change my lead screw from 12 to 24tpi?
I suppose you reason to go with the NEMA 24 not the 23 clough suggested was for more torque?
I know he said to keep things close (shorter wires) So I was going to try to use the empty space where the old contactor/capacitors were and even under the run/direction cover. I DO NOT want ANOTHER electronics box mounted by the lathe...space is limited. I just need to be careful with noise as I will have VFD and ELS now. Do you have pics of your complete setup? I have been having such problems with this site and the error messages (unsecure) its difficult to post...to like...to search, otherwise I'd try harder to find it. Every click here errors out.
 

GunsOfNavarone

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Found your pics @RJSakowski looks clean. In that thread, the great old one said he had issues running at high rpm and errors, and though I won't be threading at 2000 rpm, I will be using it for feeding the carriage. DO you have anyone power feed issues?
Also, do you know if its possible to buy a generic touch screen and use it in replacement of the control box?
 
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RJSakowski

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I will look at the half nut, honestly since it works, I have no way of deciding if it's tight or just right. Anyway of knowing/testing?
I used a small torque wrench to evaluate the torque required to turn the lead screw. If you don't have one, it is fairly easy to make a torque gauge. Turn a small pulley from a convenient material. Wood will work. Thread about 6 ft of line through the hole and wrap it around the pulley. The pulley replaces the input gear on the gear box. Attach a pull scale of appropriate sensitivity to the line. As you pull on the scale to rotate the input shaft, the scale reading times the radius of the pulley will be the torque.
Torque Gauge.JPG
I used my 20 fish scale with .1 lb resolution on a 3" diameter pulley to measure up to 480 oz-in of torque with a resolution 2.4 oz-in.

I first measured the torque required to turn the lead screw with the half nuts disengaged. Then I engaged the half nuts and noted the increase in required torque. Then I advanced the set screw as I watched the effect on the torque. The half nuts in an as shipped condition are clamped tight to the lead screw with no clearance. Adjusting the set screw will back off the half nuts, reducing friction. It will also increase backlash in the lead screw but this isn't a huge deal as threading and power feeding are done in one direction only. As noted in my post, I decreased the required torque to half of the original.
If I found that with Clough's ELS I need more torque, you're saying to run the gears at I/C but go into the code and change my lead screw from 12 to 24tpi?
That is correct.
I suppose you reason to go with the NEMA 24 not the 23 clough suggested was for more torque?
I know he said to keep things close (shorter wires) So I was going to try to use the empty space where the old contactor/capacitors were and even under the run/direction cover. I DO NOT want ANOTHER electronics box mounted by the lathe...space is limited. I just need to be careful with noise as I will have VFD and ELS now. Do you have pics of your complete setup? I have been having such problems with this site and the error messages (unsecure) its difficult to post...to like...to search, otherwise I'd try harder to find it. Every click here errors out.When I originally did my search for
When I originally did my search for a suitable motor/driver package I stumbled on the StepperOnline site and the NEMA 24 motor. The 602 oz-in. of torque was better than Clough's motor spec and the same as on my Tormach x and y axes and the cost was about half of what Clough paid. I also determined that I could fit a NEMA 24 motor in the cavity under the lathe bed. Those were my reasons for going that route.

As to mounting your electronics in the lathe housing, I think you may have a hard time fitting it all in. I would also have some concerns about any power switching that you may still have in that enclosure. I mounted my main enclosure on the back of the backsplash with the power switches mounted to that and my display above that. The box is only 3.5" deep so it doesn't take much room and if I need to work on anything, three nuts hold the entire assembly to the backsplash so I can easily move the assembly to a convenient location for service. Here are some photos.
ELS 1 .JPG
ELS 2 .JPG ELS 3 .JPG
 

kb58

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Keep in mind that if you go with a commercially available ELS, there will be additional expenses for the stepper/servo motor, gears, and belts. The Clough42 approach ran me about $350, complete.
 

GunsOfNavarone

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@kb58 I'm already in fully as far as having every part Clough recommended. I guess I just want to know what my possible issues could be and how I might go about fixing them. If I knew anything about this stuff, I would have made changes based on the issues I could see in the setup. I considered stronger stepper, but I didn't know what it would take to take it work. This way, if I do everything Clough says and purchase the same items, it should be as close to plug and play as you can get.
 

jlesser27

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[mention]GunsOfNavarone [/mention] I’m in the same boat no pun intended. Waiting on a few more parts from the big candy mountain but followed Clough42 verbatim. I have a Weiss WBF250 which is almost an exact copy of the PM1030. I think engaging the internal gearbox will be my first try if the torque doesn’t work out.


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GunsOfNavarone

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@jlesser27 I think the gearbox should be engaged (1:1) is what I believe he said. I am confused by that (and even what @RJSakowski about using A3 instead of A1) as the gearbox will no longer be connected to the motor or spindle. Almost seems you should put it between gear to where the is zero influence by the drag of the gears.
 

jlesser27

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@jlesser27 I think the gearbox should be engaged (1:1) is what I believe he said. I am confused by that (and even what @RJSakowski about using A3 instead of A1) as the gearbox will no longer be connected to the motor or spindle. Almost seems you should put it between gear to where the is zero influence by the drag of the gears.
Unfortunately I don’t have a 1:1 gear on my machine. The closest I have is a 2:1. I will have to adjust in the settings. It’s all math right it will work with some tweaking I’m sure.


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RJSakowski

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Regardless of what position the gear box selectors are in, the internal gears on the 602 are still engaged. There is no straight through shaft in the gear box. The input shaft has gears which engage gears on an intermediate shaft and another set of gears on the intermediate shaft engage gears on the output shaft.
 

kb58

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I have a long list somewhere that calculating the necessary torque will be all but impossible, as there's about a dozen variables. Picking a stepper is just a guess at best, but you can't go wrong with going a bit large. It has no effect on the code other than any gear reduction you may have.
 

ttabbal

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I used the same motor etc as Clough42 on my PM1127. It keeps up fine with the 1:1 gearbox setting. Even with some decently high feed rates.
 

jarrettbailey

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So, gears are 1.5 mod and I found a place that makes them reasonably here:


Anyone used them before? They are machinable, so if I need to modify them it's not an issue really (that I can see) and then I'll have the functionality and not have to worry about the ELS stuff (especially since it seems more expensive).

They have all of the sizes I need and it's like $230 shipped.

Thoughts?
 

ErichKeane

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So, gears are 1.5 mod and I found a place that makes them reasonably here:


Anyone used them before? They are machinable, so if I need to modify them it's not an issue really (that I can see) and then I'll have the functionality and not have to worry about the ELS stuff (especially since it seems more expensive).

They have all of the sizes I need and it's like $230 shipped.

Thoughts?
I'd be surprised if you couldn't get them cheaper than that (since they are coming from Europe), but I personally would rather gears over the ELS.

That said, ~$5/gear is a pretty good price.
 

jarrettbailey

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I'd be surprised if you couldn't get them cheaper than that (since they are coming from Europe), but I personally would rather gears over the ELS.

That said, ~$5/gear is a pretty good price.
I'd rather gears as well. I'm not old, but I learned to use old school machine tools. ;)
 

ErichKeane

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I'd rather gears as well. I'm not old, but I learned to use old school machine tools. ;)
I don't consider myself old (in my 30s), but from my perspective, gears 'just work'. Yes, there are downsides (needing to change them), but they will never skip a tooth, have software bugs, or blow a capacitor at the worst moment,

I've got a QCGB that works great. I don't have the ability to cut metric threads at the moment (my lathe predates WW2), but any imperial thread I want to cut i know I can quite easily.

If I didn't have a QCGB and no way to adapt one, I might think about an ELS.
 

kb58

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James Clough has just posted a new Youtube video announcing the availability of his controller panel -
 
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