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
 
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 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?
 
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!
 
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.
 
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.
 
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.
 
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
 
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
 
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