G4000 ELS Upgrade

[Cletus]

Hi Cletus - very cool thread here. How did you decide on the spindle to idler ratio? I’m trying to figure out what pulleys I need. Thanks.


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Well, you need your encoder rotating at the exact same speed as your spindle. So, whatever ratio your spindle to idler is, you need the same but opposing ratio from the idler to the encoder (in my case Idler 80T / Spindle 40T so 80/40=2:1). Of course you'll need to decide on and select appropriate size toothed pulleys so it will all fit within the available space when the belt couples it. Hope this helps.

 

[Ben17484]

Well, you need your encoder rotating at the exact same speed as your spindle. So, whatever ratio your spindle to idler is, you need the same but opposing ratio from the idler to the encoder (in my case Idler 80T / Spindle 40T so 80/40=2:1). Of course you'll need to decide on and select appropriate size toothed pulleys so it will all fit within the available space when the belt couples it. Hope this helps.

Thanks Cletus. To make sure I’m getting my naming of parts correct, I’ve got the following:

Highlighted red is the spindle gear at 24 teeth. Highlighted blue is the idler gear at 80 teeth. What I don’t fully understand is why choose the 80 teeth idler gear? That’s a change gear, so why do I care that it’s 80 teeth?

I’m also not sure where the TPI of the lead screw comes in to it? (8 TPI for my lathe)

Sorry for so many questions!


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[Cletus]

No problem.
Just about all of those gears will be coming out. How many teeth is the gear immediately after the 24T (red) gear? That may be a good place to attach an encoder pulley. TPI of the leadscrew and the gear ratio of the Stepper to Leadscrew pulleys will be input during the setup of the software.

This is my setup, and may make the concept a little clearer, 1:1 ratio between Spindle and encoder, 3:1 ratio stepper motor to leadscrew and a 16TPI leadscrew. The stepper info, ratio and leadscrew TPI will be input into the software during setup:

 

[Ben17484]

No problem.
Just about all of those gears will be coming out. How many teeth is the gear immediately after the 24T (red) gear? That may be a good place to attach an encoder pulley. TPI of the leadscrew and the gear ratio of the Stepper to Leadscrew pulleys will be input during the setup of the software.

This is my setup, and may make the concept a little clearer, 1:1 ratio between Spindle and encoder, 3:1 ratio stepper motor to leadscrew and a 16TPI leadscrew. The stepper info, ratio and leadscrew TPI will be input into the software during setup:

View attachment 422323

View attachment 422324

Thanks so much Cletus. So I just need a 1:1 relationship between the spindle gear and the encoder, and you chose to do that via your 80t idler gear, but it doesn’t matter how you acheive it, as long as it’s 1:1 eventually?

And then the ratio between the stepper and lead screw as well as the TPI is defined in the software/firmware. What made you decide to make it 3:1 in your case? Is that dependent on the speeds of your stepper?


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[Cletus]

Most welcome!
So I just need a 1:1 relationship between the spindle gear and the encoder, and you chose to do that via your 80t idler gear, but it doesn’t matter how you acheive it, as long as it’s 1:1 eventually? Correct.

And then the ratio between the stepper and lead screw as well as the TPI is defined in the software/firmware. Correct

What made you decide to make it 3:1 in your case? Is that dependent on the speeds of your stepper?
Wanted to ensure I had lots of torque and resolution for turning the leadscrew, I'm using a servo-stepper and I know the motor has more than enough top-end speed.

Have a look at the James' ELS videos in particular these two on the subject, hope this helps

 

[Ben17484]

Thanks Cletus. I rewatched those today as well as another YouTube set of videos by ‘routercnc’ and I think everything makes sense to me now. I’ve got all of the equipment (other than pulleys, but I now know what I need) I just need to figure out how to fit it all together and to the lathe


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[Cletus]

Great! ........... you will like it. I use mine nearly every day

 

[weejax]

hey cletus, im in the process of this build. ive got the same lathe as you (central machinery version). Im probably going to set it up the same as you and clough did. On the grizzly model clough has (0602) i believe it power feeds/threads via half nut. on our models we have the keyed lead screw for the power feeds. was wondering what your experience has been using the power feed with the ELS. I think the program that clough wrote assumes you are using a half nut. id like to not use the half nut for power feed to try and extend the life.

 

[Cletus]

Oh absolutely! I only use the half nuts when threading. When power feeding, I'm using the keyed leadscrew mechanism. You can change feedrate on the fly using the ELS.

 

[weejax]

Oh absolutely! I only use the half nuts when threading. When power feeding, I'm using the keyed leadscrew mechanism. You can change feedrate on the fly using the ELS.

thanks--im trying to figure out how you would calculate SFM--im a rookie so like to use the charts for that stuff. i think the ELS gives you thou/rev right? how do you figure out your feed rates? thanks for any advice.